Research ArticleSize-Controlled Synthesis of Fe3O4 Magnetic Nanoparticles inthe Layers of Montmorillonite

Katayoon Kalantari Mansor B Ahmad Kamyar Shameli Mohd Zobir Bin HusseinRoshanak Khandanlou and Hajar Khanehzaei

Department of Chemistry Faculty of Science Universiti Putra Malaysia (UPM) 43400 Serdang Selangor Malaysia

Correspondence should be addressed to Katayoon Kalantari ka upmyahoocom andMansor B Ahmad mansorahmadupmedumy

Received 9 June 2014 Accepted 4 August 2014 Published 15 September 2014

Academic Editor Hongchen Chen Gu

Copyright copy 2014 Katayoon Kalantari et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Iron oxide nanoparticles (Fe3O4-NPs) were synthesized using chemical coprecipitation method Fe

3O4-NPs are located in

interlamellar space and external surfaces ofmontmorillonite (MMT) as a solid supported at room temperatureThe size ofmagnetitenanoparticles could be controlled by varying the amount of NaOH as reducing agent in the medium The interlamellar spacechanged from 124 nm to 285 nm and average diameter of Fe

3O4nanoparticles was from 1288 nm to 824 nm The synthesized

nanoparticles were characterized using some instruments such as transmission electron microscopy powder X-ray diffractionenergy dispersive X-ray spectroscopy field emission scanning electron microscopy vibrating sample magnetometer and Fouriertransform infrared spectroscopy

1 Introduction

In recent years considerable attention has been paid to ironoxides especially on magnetic (Fe

3O4) nanoparticles due

to their potential applications such as pigment magneticresonance imaging magnetic drug delivery Ferro fluidsrecording material and data storage media [1 2] Thereare many reports on the synthesis and characterization ofmagnetic nanoparticles this is due to its significance invarious fields especially when this material is made at thenanoscale Magnetic nanoparticles have been prepared byvarious methods such as arc discharge mechanical grindinglaser ablation microemulsion and high temperature decom-position of organic precursors [3] However research is stillgoing on to obtain well-dispersed magnetic nanoparticles

Severalmethods have been developed recently for prepar-ing magnetic nanoparticles including coprecipitation [4]sol-gel method [5] hydrothermal process [6] and thesolvothermal method [7] Among these methods coprecip-itation is considered as the simplest most efficient and mosteconomic method

However there are three major challenges that thesenanoparticles present One is related to easy oxidationdis-solution of magnetic nanoparticles (NPs) The other twodrawbacks are the difficulty in recycling such small sizedNPs and coaggregation of nanoparticles in which case leadsto decrease the effective surface area of nanoparticles andthus reduce their reaction activities In order to protect themagnetic NPs against oxidation a shell structure is oftenintroduced such as a silica shell or polymer shell [8] Severalmethods have been accordingly developed to minimize thecoaggregation of nanoparticles obtain the soft sediment andimprove their manipulation such as supporting of magneticnanoparticles on polymers or inorganic matter like poroussilica [9 10]

Clay minerals which are abundant and environmen-tal friendly are used as the supporting materials of mag-netic nanoparticles Sodium montmorillonite (Na-MMT)(Na07(Al33Mg07) Si8O20(OH)4nH2O) a kind of 2 1 type

layered silicates in which each layer comprises an aluminaoctahedral sheet sandwiched between two silica tetrahedralsheets is known as a polymermodifier due to its high specificsurface area [11]

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2014 Article ID 739485 9 pageshttpdxdoiorg1011552014739485

2 Journal of Nanomaterials

Such layers are stacked by weak dipolar or van der Waalsforces leading to the interaction of charge compensatingcations into the interlayer space Therefore not only adsorp-tion on the external surface but also intercalation into theinterlayer space can occur [12]

Here we present our results obtained from synthesizedmagnetic nanoparticles well dispersed on montmorilloniteusing sodium hydroxide as a reducing agent

2 Materials and Methods

In this work all reagents were of analytical grade Ferricchloride hexahydrate (FeCl

36H2O) and ferrous chloride

tetrahydrate (FeCl24H2O) of 96wt were used as the iron

precursors and also montmorillonite powder was obtainedfrom (Kunipia-F Tokyo Japan) NaOH of 99wt wasobtained from Merck KGaA (Darmstadt Germany) Allsolutions were freshly prepared using deionized water

21 Fe3O4Montmorillonite NCs Preparation The Fe

3O4

nanoparticles were synthesized using chemical coprecipita-tion method Prior to use all glassware used in experimentalprocedures were cleaned in a fresh solution of HNO

3HCl

(3 1 vv) washed thoroughly with double distilledwater anddried For the synthesis of Fe

3O4montmorillonite nanocom-

posites (Fe3O4MMT NCs) different volumes of deionized

water were bubbled by N2gas for 15min and then 20 g of

montmorillonite and measured amount of Fe3+ and Fe2+with a molar ratio of 1 2 were successively dissolved inultrapurewater with vigorousmechanical stirring for 2 hoursUnder the protection of nitrogen gas 150 30 50 750950 and 1250mL of 2M NaOH were added dropwise intothe above solutions Eventually the Fe

3O4-NPs content of

the MMT matrix was 10 30 50 70 90 and 120 wt respectively After that the mechanical stirrer was switchedoff and Fe

3O4-NPs settled gradually The suspensions were

finally centrifuged washed twice with ethanol and distilledwater and kept in a vacuum stove at 100∘C

22 Characterization The structures of the synthesizedFe3O4-NPs in MMT were examined using Philips Xrsquopert

PXRD (copper K120572 radiation PANalytical Almelo TheNetherlands) The changes in the interlamellar spacing ofMMT were also studied by using PXRD in the small-angle range of 2120579 (5ndash15 degrees) The scan speed of 2degreesminutes was applied to PXRD patterns recordingTEM images of the samples were recorded with an H-7100 electron microscope (Hitachi Ltd Tokyo Japan) Thesamples were prepared by dispersing about 01 g powderwith 8mL ethanol by ultrasound for 20min A drop ofthe dispersion was applied to a holey carbon TEM supportgrid Excess solution was blotted off using a filter paperThe analysis of the surface morphologies of the sampleswas performed with an (XL 30 Philips) environmentalscanning electron microscope (SEM) The cleaned and driedsamples were first coated with gold using sputter coater Forelemental analysis of the nanoparticles energy dispersion

X-ray spectroscopy was carried out on a Shimadzu EDX-700HS spectrometer attached to the SEM The FTIR spec-trum was used to identify the functional groups presentin the synthesized compound FTIR spectra were recordedover the range of 200ndash4000 cmminus1 utilizing the Series 100FTIR 1650 spectrophotometer (PerkinElmer Waltham MAUSA) Magnetization measurements were carried out witha Lakeshore (model 7407) vibrating sample magnetome-ter (VSM) to study magnetic properties of the Fe

3O4

nanoparticles under magnetic field up to 10 kG at roomtemperature

3 Results and Discussion

The customized shape and size of prepared magneticnanoparticles have been a challenge in scientific and tech-nological issues The wet chemical methods to magneticnanoparticles are more effective and simpler with goodcontrol over composition and size [13] Fe

3O4-NPs can

be prepared through the coprecipitation of Fe3+ and Fe2+aqueous salts solution by addition of base as reducing agentThe chemical reaction may be presented as follows [14]

Fe2+Fe3+MMT + 8OHminus 997888rarr Fe3O4MMT NCs + 4H

2O(1)

The surface of MMT is assisting the Fe3O4-NPs nucle-

ation during the reduction processThe schematic illustrationof the synthesis of Fe

3O4MMT NCs from MMTFe3+ndashFe2+

suspension produced by using sodium hydroxide is shownin Figure 1 Meanwhile as shown in Figure 2 the MMTsuspension was gray (a) and the addition of Fe3+ndashFe2+ ions tothe MMT change color to the light brown (b) brown (c) anddark brown (d) for 10 70 and 120 wt respectively butafter the addition of NaOH to the suspensions they turnedto black color (e) (f) and (g) that indicate the abundance ofFe3O4-NPs in the MMT suspensions

31 Powder X-Ray Diffraction The basal spacing of MMT(Figure 3(a)) was 124 nm at 2120579∘ 883∘ Combination withFe3O4NPs expanded the basal spacing to 147 168 187 210

253 and 285 nm at the 2120579∘ 875∘ 866∘ 851∘ 821∘ 772∘ and746∘ in 10 30 50 70 90 and 120 wt respectively It maybe assumed that the iron ions penetrated into the interlayerspace of montmorillonite via ion-exchange and were reducedby NaOH to Fe

3O4NPs In this case the interlayer space

would have acted as a size controller and microreactor [15]Moreover the intensities of the reflections were significantlydecreased and the highly ordered parallel lamellar structureof the MMT was disrupted by the Fe

3O4-NPs formation [16]

Figure 3(b) reveals X-ray diffraction patterns of preparedFe3O4-NPs The reflections of Fe

3O4-NPs at 2120579∘ 3162∘

3578∘ 4384∘ 5967∘ 6253∘ and 7458∘ are related to the220 311 400 511 440 and 622 crystalline structure with aspinel structure Comparing XRD pattern of synthesized NPswith the standard diffraction spectrum (ref code Fe

3O401-

088-0315) the synthesized product is crystalline Fe3O4[17]

The size of Fe3O4-NPs is significantly influenced by the kind

of reducing agent used in the reaction Generally a strong

Journal of Nanomaterials 3

FeCl3 middot 6H2O + FeCl2 middot 4H2O[2 1 molar ratio]

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

OH

SiAl

OH

SiAl

Time 2h

Mixing at room temperature

ds=147

minus285

nm

ds=124

nm

Fe3O4

Fe3O4Fe3O4Fe3O4Fe3O4Fe3O4

Fe3O4

Fe3O4 Fe3O4 Fe3O4

Fe3O4

Fe3O4

Fe3O4

Fe3O4Fe3O4 Fe3O4

(a)

(b)

NaOH [aq] [2M]

Figure 1 Schematic illustration of the synthesized Fe3O4-NPs in the interlayer space of MMT suspension by chemical coprecipitation

reduction method ((a)-(b))

(a) (b) (c) (d) (e) (f) (g)

Figure 2 Photograph of montmorillonite suspension (a) and Fe2+Fe3+MMT suspension at different Fe2+Fe3+concentrations (b) 10 (c)70 (d) 120 and Fe

3O4MMT NCs (e) 10 (f) 70 and (g) 120

4 Journal of Nanomaterials

746∘(H)

(F)

(E)

(D)

(C)

(B)

(A)

285nm772∘

253nm

821∘

210nm851∘

187nm866∘

168nm875∘

147nm

883∘

124nm

Inte

nsity

(au

)

2120579 (deg)5 6 7 8 9 10 11 12

(a)

(H)

(F)

(E)

(D)

(C)

(B)

(A)

2120579 (deg)30 35 40 45 50 55 60 65 70 75 80

(220)(311)

(400)(511)

(440)(622)

Inte

nsity

(au

)

3162∘3578∘

4384∘5967∘

6253∘7458∘

Fe3O4 magnetite nanoparticlesReference code 01-088-0315

MMT

MMTFe3O4-NCs (12wt)

MMTFe3O4-NCs (7wt)

MMTFe3O4-NCs (3wt)

(b)

Figure 3 (a) Powder X-ray diffraction patterns of MMT (a) and Fe3O4MMTNCs for determination of d-spacing (119889s) and crystals structure

at different percentage of NPs (10 30 50 70 90 and 120 wt ((b)ndash(f))) (b) Powder X-ray diffraction patterns of MMT (a) and MMTndashFe3O4-NCs for determination of Fe

3O4crystal structure (b)ndash(h) 1 3 5 7 9 and 12 (ww)

reducing agent promotes a fast rate and favors the formationof smaller NPsMeanwhile we have found that the amount ofNaOH has a significant effect on the size of Fe

3O4-NPs [18]

and increasing the NaOH amount will lead up to the decreaseof Fe3O4-NPs size gradually The possible reason is that

repulsive force between hydroxide ions hinders the growthof crystal grains when the excess hydroxide ions producedfrom NaOH are adsorbed on the surface of crystal nuclei[19] Additionally as shown in Figure 3(b) Fe

3O4MMT

NCs 120 wt completely absorbed when exposed to an

external magnetic field and the response decreased with thedecreasing in Fe

3O4percentage

32 Transmission Electron Microscopy (TEM) Figure 4shows TEM images of Fe

3O4-NPs in the interlayer space

or on the montmorillonite surface The size distributionhistograms of Fe

3O4MMT NCs in Figures 4(a)ndash4(d) were

determined by measuring the diameter of 824 1038 1257and 1288 nm for 10 50 90 and 120 wt respectively Due

Journal of Nanomaterials 5

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1288

N = 43Std dev = 1971

(a)

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1257

N = 31

Std dev = 1807

(b)

0 2 4 6 8 10 12 14 16 18 20 22 24

Particle diameter (nm)

0

2

4

6

8

10

12

Freq

uenc

y

Mean = 1038

N = 26Std dev = 2755

(c)

0 2 4 6 8 10 12 14

Particle diameter (nm)

0

2

4

6

8

Freq

uenc

y

Mean = 824

N = 37

Std dev = 1258

(d)

Figure 4 The transmission electron microscopy images and particle size distribution histogram for 10 50 90 and 120 wt of theFe3O4MMT NCs

6 Journal of Nanomaterials

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(a)

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(b)

Figure 5 The scanning electron microscopy micrographs of Fe3O4MMT NCs with high magnification for 10 and 120 wt (a) and (b)

times2500 SEM10120583m

(a)

times2500 SEM10120583m

(b)

times2500 SEM10120583m

(c)

times2500 SEM10120583m

(d)

Figure 6 The scanning electron microscopy micrographs of MMT (a) and Fe3O4MMT NCs for 50 90 and 120 wt (b) (c) and (d)

to the high density of ion-exchange sites on MMT the highlycharged Fe

3O4-NPs are strongly bound via electrostatic

interaction to the surface The higher abundance of NPsaggregates in the MMT composite is in direct correlationwith the smaller primary NPs dimensions [20]

33 Scanning Electron Microscopy (SEM) SEM images showthat the Fe

3O4-NPs are in spherical shape (Figures 5(a)

and 5(b)) Fe3O4-NPs have very high surface free energy

which lead to instability in their dispersions thermodynamic

system stability is restored upon Ostwald ripening [21] Theisotopic nucleation rate per unit area at the interface betweenthe Fe

3O4-NPs leads to forming the spherical shape NPs

due to equivalent growth rate along every direction of thenucleation as the sphere has the smallest surface area per unitvolume compared to other shapes [22] Figure 6 clearly showsthat the size of Fe

3O4-NPs in 10 wt sample is smaller than

120 wt which is in line with the TEM and XRD resultspreviously mentioned

A general view of the MMT with a typical sheet-likestructure with large flakes can be observed in Figure 6(a)

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

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Nano

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

2 Journal of Nanomaterials

Such layers are stacked by weak dipolar or van der Waalsforces leading to the interaction of charge compensatingcations into the interlayer space Therefore not only adsorp-tion on the external surface but also intercalation into theinterlayer space can occur [12]

Here we present our results obtained from synthesizedmagnetic nanoparticles well dispersed on montmorilloniteusing sodium hydroxide as a reducing agent

2 Materials and Methods

In this work all reagents were of analytical grade Ferricchloride hexahydrate (FeCl

36H2O) and ferrous chloride

tetrahydrate (FeCl24H2O) of 96wt were used as the iron

precursors and also montmorillonite powder was obtainedfrom (Kunipia-F Tokyo Japan) NaOH of 99wt wasobtained from Merck KGaA (Darmstadt Germany) Allsolutions were freshly prepared using deionized water

21 Fe3O4Montmorillonite NCs Preparation The Fe

3O4

nanoparticles were synthesized using chemical coprecipita-tion method Prior to use all glassware used in experimentalprocedures were cleaned in a fresh solution of HNO

3HCl

(3 1 vv) washed thoroughly with double distilledwater anddried For the synthesis of Fe

3O4montmorillonite nanocom-

posites (Fe3O4MMT NCs) different volumes of deionized

water were bubbled by N2gas for 15min and then 20 g of

montmorillonite and measured amount of Fe3+ and Fe2+with a molar ratio of 1 2 were successively dissolved inultrapurewater with vigorousmechanical stirring for 2 hoursUnder the protection of nitrogen gas 150 30 50 750950 and 1250mL of 2M NaOH were added dropwise intothe above solutions Eventually the Fe

3O4-NPs content of

the MMT matrix was 10 30 50 70 90 and 120 wt respectively After that the mechanical stirrer was switchedoff and Fe

3O4-NPs settled gradually The suspensions were

finally centrifuged washed twice with ethanol and distilledwater and kept in a vacuum stove at 100∘C

22 Characterization The structures of the synthesizedFe3O4-NPs in MMT were examined using Philips Xrsquopert

PXRD (copper K120572 radiation PANalytical Almelo TheNetherlands) The changes in the interlamellar spacing ofMMT were also studied by using PXRD in the small-angle range of 2120579 (5ndash15 degrees) The scan speed of 2degreesminutes was applied to PXRD patterns recordingTEM images of the samples were recorded with an H-7100 electron microscope (Hitachi Ltd Tokyo Japan) Thesamples were prepared by dispersing about 01 g powderwith 8mL ethanol by ultrasound for 20min A drop ofthe dispersion was applied to a holey carbon TEM supportgrid Excess solution was blotted off using a filter paperThe analysis of the surface morphologies of the sampleswas performed with an (XL 30 Philips) environmentalscanning electron microscope (SEM) The cleaned and driedsamples were first coated with gold using sputter coater Forelemental analysis of the nanoparticles energy dispersion

X-ray spectroscopy was carried out on a Shimadzu EDX-700HS spectrometer attached to the SEM The FTIR spec-trum was used to identify the functional groups presentin the synthesized compound FTIR spectra were recordedover the range of 200ndash4000 cmminus1 utilizing the Series 100FTIR 1650 spectrophotometer (PerkinElmer Waltham MAUSA) Magnetization measurements were carried out witha Lakeshore (model 7407) vibrating sample magnetome-ter (VSM) to study magnetic properties of the Fe

3O4

nanoparticles under magnetic field up to 10 kG at roomtemperature

3 Results and Discussion

The customized shape and size of prepared magneticnanoparticles have been a challenge in scientific and tech-nological issues The wet chemical methods to magneticnanoparticles are more effective and simpler with goodcontrol over composition and size [13] Fe

3O4-NPs can

be prepared through the coprecipitation of Fe3+ and Fe2+aqueous salts solution by addition of base as reducing agentThe chemical reaction may be presented as follows [14]

Fe2+Fe3+MMT + 8OHminus 997888rarr Fe3O4MMT NCs + 4H

2O(1)

The surface of MMT is assisting the Fe3O4-NPs nucle-

ation during the reduction processThe schematic illustrationof the synthesis of Fe

3O4MMT NCs from MMTFe3+ndashFe2+

suspension produced by using sodium hydroxide is shownin Figure 1 Meanwhile as shown in Figure 2 the MMTsuspension was gray (a) and the addition of Fe3+ndashFe2+ ions tothe MMT change color to the light brown (b) brown (c) anddark brown (d) for 10 70 and 120 wt respectively butafter the addition of NaOH to the suspensions they turnedto black color (e) (f) and (g) that indicate the abundance ofFe3O4-NPs in the MMT suspensions

31 Powder X-Ray Diffraction The basal spacing of MMT(Figure 3(a)) was 124 nm at 2120579∘ 883∘ Combination withFe3O4NPs expanded the basal spacing to 147 168 187 210

253 and 285 nm at the 2120579∘ 875∘ 866∘ 851∘ 821∘ 772∘ and746∘ in 10 30 50 70 90 and 120 wt respectively It maybe assumed that the iron ions penetrated into the interlayerspace of montmorillonite via ion-exchange and were reducedby NaOH to Fe

3O4NPs In this case the interlayer space

would have acted as a size controller and microreactor [15]Moreover the intensities of the reflections were significantlydecreased and the highly ordered parallel lamellar structureof the MMT was disrupted by the Fe

3O4-NPs formation [16]

Figure 3(b) reveals X-ray diffraction patterns of preparedFe3O4-NPs The reflections of Fe

3O4-NPs at 2120579∘ 3162∘

3578∘ 4384∘ 5967∘ 6253∘ and 7458∘ are related to the220 311 400 511 440 and 622 crystalline structure with aspinel structure Comparing XRD pattern of synthesized NPswith the standard diffraction spectrum (ref code Fe

3O401-

088-0315) the synthesized product is crystalline Fe3O4[17]

The size of Fe3O4-NPs is significantly influenced by the kind

of reducing agent used in the reaction Generally a strong

Journal of Nanomaterials 3

FeCl3 middot 6H2O + FeCl2 middot 4H2O[2 1 molar ratio]

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

OH

SiAl

OH

SiAl

Time 2h

Mixing at room temperature

ds=147

minus285

nm

ds=124

nm

Fe3O4

Fe3O4Fe3O4Fe3O4Fe3O4Fe3O4

Fe3O4

Fe3O4 Fe3O4 Fe3O4

Fe3O4

Fe3O4

Fe3O4

Fe3O4Fe3O4 Fe3O4

(a)

(b)

NaOH [aq] [2M]

Figure 1 Schematic illustration of the synthesized Fe3O4-NPs in the interlayer space of MMT suspension by chemical coprecipitation

reduction method ((a)-(b))

(a) (b) (c) (d) (e) (f) (g)

Figure 2 Photograph of montmorillonite suspension (a) and Fe2+Fe3+MMT suspension at different Fe2+Fe3+concentrations (b) 10 (c)70 (d) 120 and Fe

3O4MMT NCs (e) 10 (f) 70 and (g) 120

4 Journal of Nanomaterials

746∘(H)

(F)

(E)

(D)

(C)

(B)

(A)

285nm772∘

253nm

821∘

210nm851∘

187nm866∘

168nm875∘

147nm

883∘

124nm

Inte

nsity

(au

)

2120579 (deg)5 6 7 8 9 10 11 12

(a)

(H)

(F)

(E)

(D)

(C)

(B)

(A)

2120579 (deg)30 35 40 45 50 55 60 65 70 75 80

(220)(311)

(400)(511)

(440)(622)

Inte

nsity

(au

)

3162∘3578∘

4384∘5967∘

6253∘7458∘

Fe3O4 magnetite nanoparticlesReference code 01-088-0315

MMT

MMTFe3O4-NCs (12wt)

MMTFe3O4-NCs (7wt)

MMTFe3O4-NCs (3wt)

(b)

Figure 3 (a) Powder X-ray diffraction patterns of MMT (a) and Fe3O4MMTNCs for determination of d-spacing (119889s) and crystals structure

at different percentage of NPs (10 30 50 70 90 and 120 wt ((b)ndash(f))) (b) Powder X-ray diffraction patterns of MMT (a) and MMTndashFe3O4-NCs for determination of Fe

3O4crystal structure (b)ndash(h) 1 3 5 7 9 and 12 (ww)

reducing agent promotes a fast rate and favors the formationof smaller NPsMeanwhile we have found that the amount ofNaOH has a significant effect on the size of Fe

3O4-NPs [18]

and increasing the NaOH amount will lead up to the decreaseof Fe3O4-NPs size gradually The possible reason is that

repulsive force between hydroxide ions hinders the growthof crystal grains when the excess hydroxide ions producedfrom NaOH are adsorbed on the surface of crystal nuclei[19] Additionally as shown in Figure 3(b) Fe

3O4MMT

NCs 120 wt completely absorbed when exposed to an

external magnetic field and the response decreased with thedecreasing in Fe

3O4percentage

32 Transmission Electron Microscopy (TEM) Figure 4shows TEM images of Fe

3O4-NPs in the interlayer space

or on the montmorillonite surface The size distributionhistograms of Fe

3O4MMT NCs in Figures 4(a)ndash4(d) were

determined by measuring the diameter of 824 1038 1257and 1288 nm for 10 50 90 and 120 wt respectively Due

Journal of Nanomaterials 5

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1288

N = 43Std dev = 1971

(a)

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1257

N = 31

Std dev = 1807

(b)

0 2 4 6 8 10 12 14 16 18 20 22 24

Particle diameter (nm)

0

2

4

6

8

10

12

Freq

uenc

y

Mean = 1038

N = 26Std dev = 2755

(c)

0 2 4 6 8 10 12 14

Particle diameter (nm)

0

2

4

6

8

Freq

uenc

y

Mean = 824

N = 37

Std dev = 1258

(d)

Figure 4 The transmission electron microscopy images and particle size distribution histogram for 10 50 90 and 120 wt of theFe3O4MMT NCs

6 Journal of Nanomaterials

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(a)

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(b)

Figure 5 The scanning electron microscopy micrographs of Fe3O4MMT NCs with high magnification for 10 and 120 wt (a) and (b)

times2500 SEM10120583m

(a)

times2500 SEM10120583m

(b)

times2500 SEM10120583m

(c)

times2500 SEM10120583m

(d)

Figure 6 The scanning electron microscopy micrographs of MMT (a) and Fe3O4MMT NCs for 50 90 and 120 wt (b) (c) and (d)

to the high density of ion-exchange sites on MMT the highlycharged Fe

3O4-NPs are strongly bound via electrostatic

interaction to the surface The higher abundance of NPsaggregates in the MMT composite is in direct correlationwith the smaller primary NPs dimensions [20]

33 Scanning Electron Microscopy (SEM) SEM images showthat the Fe

3O4-NPs are in spherical shape (Figures 5(a)

and 5(b)) Fe3O4-NPs have very high surface free energy

which lead to instability in their dispersions thermodynamic

system stability is restored upon Ostwald ripening [21] Theisotopic nucleation rate per unit area at the interface betweenthe Fe

3O4-NPs leads to forming the spherical shape NPs

due to equivalent growth rate along every direction of thenucleation as the sphere has the smallest surface area per unitvolume compared to other shapes [22] Figure 6 clearly showsthat the size of Fe

3O4-NPs in 10 wt sample is smaller than

120 wt which is in line with the TEM and XRD resultspreviously mentioned

A general view of the MMT with a typical sheet-likestructure with large flakes can be observed in Figure 6(a)

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

Journal of Nanomaterials 3

FeCl3 middot 6H2O + FeCl2 middot 4H2O[2 1 molar ratio]

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+Na+

Na+Na+

Na+Na+

Na+

OH

SiAl

OH

SiAl

Time 2h

Mixing at room temperature

ds=147

minus285

nm

ds=124

nm

Fe3O4

Fe3O4Fe3O4Fe3O4Fe3O4Fe3O4

Fe3O4

Fe3O4 Fe3O4 Fe3O4

Fe3O4

Fe3O4

Fe3O4

Fe3O4Fe3O4 Fe3O4

(a)

(b)

NaOH [aq] [2M]

Figure 1 Schematic illustration of the synthesized Fe3O4-NPs in the interlayer space of MMT suspension by chemical coprecipitation

reduction method ((a)-(b))

(a) (b) (c) (d) (e) (f) (g)

Figure 2 Photograph of montmorillonite suspension (a) and Fe2+Fe3+MMT suspension at different Fe2+Fe3+concentrations (b) 10 (c)70 (d) 120 and Fe

3O4MMT NCs (e) 10 (f) 70 and (g) 120

4 Journal of Nanomaterials

746∘(H)

(F)

(E)

(D)

(C)

(B)

(A)

285nm772∘

253nm

821∘

210nm851∘

187nm866∘

168nm875∘

147nm

883∘

124nm

Inte

nsity

(au

)

2120579 (deg)5 6 7 8 9 10 11 12

(a)

(H)

(F)

(E)

(D)

(C)

(B)

(A)

2120579 (deg)30 35 40 45 50 55 60 65 70 75 80

(220)(311)

(400)(511)

(440)(622)

Inte

nsity

(au

)

3162∘3578∘

4384∘5967∘

6253∘7458∘

Fe3O4 magnetite nanoparticlesReference code 01-088-0315

MMT

MMTFe3O4-NCs (12wt)

MMTFe3O4-NCs (7wt)

MMTFe3O4-NCs (3wt)

(b)

Figure 3 (a) Powder X-ray diffraction patterns of MMT (a) and Fe3O4MMTNCs for determination of d-spacing (119889s) and crystals structure

at different percentage of NPs (10 30 50 70 90 and 120 wt ((b)ndash(f))) (b) Powder X-ray diffraction patterns of MMT (a) and MMTndashFe3O4-NCs for determination of Fe

3O4crystal structure (b)ndash(h) 1 3 5 7 9 and 12 (ww)

reducing agent promotes a fast rate and favors the formationof smaller NPsMeanwhile we have found that the amount ofNaOH has a significant effect on the size of Fe

3O4-NPs [18]

and increasing the NaOH amount will lead up to the decreaseof Fe3O4-NPs size gradually The possible reason is that

repulsive force between hydroxide ions hinders the growthof crystal grains when the excess hydroxide ions producedfrom NaOH are adsorbed on the surface of crystal nuclei[19] Additionally as shown in Figure 3(b) Fe

3O4MMT

NCs 120 wt completely absorbed when exposed to an

external magnetic field and the response decreased with thedecreasing in Fe

3O4percentage

32 Transmission Electron Microscopy (TEM) Figure 4shows TEM images of Fe

3O4-NPs in the interlayer space

or on the montmorillonite surface The size distributionhistograms of Fe

3O4MMT NCs in Figures 4(a)ndash4(d) were

determined by measuring the diameter of 824 1038 1257and 1288 nm for 10 50 90 and 120 wt respectively Due

Journal of Nanomaterials 5

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1288

N = 43Std dev = 1971

(a)

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1257

N = 31

Std dev = 1807

(b)

0 2 4 6 8 10 12 14 16 18 20 22 24

Particle diameter (nm)

0

2

4

6

8

10

12

Freq

uenc

y

Mean = 1038

N = 26Std dev = 2755

(c)

0 2 4 6 8 10 12 14

Particle diameter (nm)

0

2

4

6

8

Freq

uenc

y

Mean = 824

N = 37

Std dev = 1258

(d)

Figure 4 The transmission electron microscopy images and particle size distribution histogram for 10 50 90 and 120 wt of theFe3O4MMT NCs

6 Journal of Nanomaterials

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(a)

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(b)

Figure 5 The scanning electron microscopy micrographs of Fe3O4MMT NCs with high magnification for 10 and 120 wt (a) and (b)

times2500 SEM10120583m

(a)

times2500 SEM10120583m

(b)

times2500 SEM10120583m

(c)

times2500 SEM10120583m

(d)

Figure 6 The scanning electron microscopy micrographs of MMT (a) and Fe3O4MMT NCs for 50 90 and 120 wt (b) (c) and (d)

to the high density of ion-exchange sites on MMT the highlycharged Fe

3O4-NPs are strongly bound via electrostatic

interaction to the surface The higher abundance of NPsaggregates in the MMT composite is in direct correlationwith the smaller primary NPs dimensions [20]

33 Scanning Electron Microscopy (SEM) SEM images showthat the Fe

3O4-NPs are in spherical shape (Figures 5(a)

and 5(b)) Fe3O4-NPs have very high surface free energy

which lead to instability in their dispersions thermodynamic

system stability is restored upon Ostwald ripening [21] Theisotopic nucleation rate per unit area at the interface betweenthe Fe

3O4-NPs leads to forming the spherical shape NPs

due to equivalent growth rate along every direction of thenucleation as the sphere has the smallest surface area per unitvolume compared to other shapes [22] Figure 6 clearly showsthat the size of Fe

3O4-NPs in 10 wt sample is smaller than

120 wt which is in line with the TEM and XRD resultspreviously mentioned

A general view of the MMT with a typical sheet-likestructure with large flakes can be observed in Figure 6(a)

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

4 Journal of Nanomaterials

746∘(H)

(F)

(E)

(D)

(C)

(B)

(A)

285nm772∘

253nm

821∘

210nm851∘

187nm866∘

168nm875∘

147nm

883∘

124nm

Inte

nsity

(au

)

2120579 (deg)5 6 7 8 9 10 11 12

(a)

(H)

(F)

(E)

(D)

(C)

(B)

(A)

2120579 (deg)30 35 40 45 50 55 60 65 70 75 80

(220)(311)

(400)(511)

(440)(622)

Inte

nsity

(au

)

3162∘3578∘

4384∘5967∘

6253∘7458∘

Fe3O4 magnetite nanoparticlesReference code 01-088-0315

MMT

MMTFe3O4-NCs (12wt)

MMTFe3O4-NCs (7wt)

MMTFe3O4-NCs (3wt)

(b)

Figure 3 (a) Powder X-ray diffraction patterns of MMT (a) and Fe3O4MMTNCs for determination of d-spacing (119889s) and crystals structure

at different percentage of NPs (10 30 50 70 90 and 120 wt ((b)ndash(f))) (b) Powder X-ray diffraction patterns of MMT (a) and MMTndashFe3O4-NCs for determination of Fe

3O4crystal structure (b)ndash(h) 1 3 5 7 9 and 12 (ww)

reducing agent promotes a fast rate and favors the formationof smaller NPsMeanwhile we have found that the amount ofNaOH has a significant effect on the size of Fe

3O4-NPs [18]

and increasing the NaOH amount will lead up to the decreaseof Fe3O4-NPs size gradually The possible reason is that

repulsive force between hydroxide ions hinders the growthof crystal grains when the excess hydroxide ions producedfrom NaOH are adsorbed on the surface of crystal nuclei[19] Additionally as shown in Figure 3(b) Fe

3O4MMT

NCs 120 wt completely absorbed when exposed to an

external magnetic field and the response decreased with thedecreasing in Fe

3O4percentage

32 Transmission Electron Microscopy (TEM) Figure 4shows TEM images of Fe

3O4-NPs in the interlayer space

or on the montmorillonite surface The size distributionhistograms of Fe

3O4MMT NCs in Figures 4(a)ndash4(d) were

determined by measuring the diameter of 824 1038 1257and 1288 nm for 10 50 90 and 120 wt respectively Due

Journal of Nanomaterials 5

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1288

N = 43Std dev = 1971

(a)

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1257

N = 31

Std dev = 1807

(b)

0 2 4 6 8 10 12 14 16 18 20 22 24

Particle diameter (nm)

0

2

4

6

8

10

12

Freq

uenc

y

Mean = 1038

N = 26Std dev = 2755

(c)

0 2 4 6 8 10 12 14

Particle diameter (nm)

0

2

4

6

8

Freq

uenc

y

Mean = 824

N = 37

Std dev = 1258

(d)

Figure 4 The transmission electron microscopy images and particle size distribution histogram for 10 50 90 and 120 wt of theFe3O4MMT NCs

6 Journal of Nanomaterials

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(a)

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(b)

Figure 5 The scanning electron microscopy micrographs of Fe3O4MMT NCs with high magnification for 10 and 120 wt (a) and (b)

times2500 SEM10120583m

(a)

times2500 SEM10120583m

(b)

times2500 SEM10120583m

(c)

times2500 SEM10120583m

(d)

Figure 6 The scanning electron microscopy micrographs of MMT (a) and Fe3O4MMT NCs for 50 90 and 120 wt (b) (c) and (d)

to the high density of ion-exchange sites on MMT the highlycharged Fe

3O4-NPs are strongly bound via electrostatic

interaction to the surface The higher abundance of NPsaggregates in the MMT composite is in direct correlationwith the smaller primary NPs dimensions [20]

33 Scanning Electron Microscopy (SEM) SEM images showthat the Fe

3O4-NPs are in spherical shape (Figures 5(a)

and 5(b)) Fe3O4-NPs have very high surface free energy

which lead to instability in their dispersions thermodynamic

system stability is restored upon Ostwald ripening [21] Theisotopic nucleation rate per unit area at the interface betweenthe Fe

3O4-NPs leads to forming the spherical shape NPs

due to equivalent growth rate along every direction of thenucleation as the sphere has the smallest surface area per unitvolume compared to other shapes [22] Figure 6 clearly showsthat the size of Fe

3O4-NPs in 10 wt sample is smaller than

120 wt which is in line with the TEM and XRD resultspreviously mentioned

A general view of the MMT with a typical sheet-likestructure with large flakes can be observed in Figure 6(a)

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

Journal of Nanomaterials 5

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1288

N = 43Std dev = 1971

(a)

0 2 4 6 8 10

0

2

4

6

8

10

12 14 16 18 20

Particle diameter (nm)

Freq

uenc

y

Mean = 1257

N = 31

Std dev = 1807

(b)

0 2 4 6 8 10 12 14 16 18 20 22 24

Particle diameter (nm)

0

2

4

6

8

10

12

Freq

uenc

y

Mean = 1038

N = 26Std dev = 2755

(c)

0 2 4 6 8 10 12 14

Particle diameter (nm)

0

2

4

6

8

Freq

uenc

y

Mean = 824

N = 37

Std dev = 1258

(d)

Figure 4 The transmission electron microscopy images and particle size distribution histogram for 10 50 90 and 120 wt of theFe3O4MMT NCs

6 Journal of Nanomaterials

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(a)

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(b)

Figure 5 The scanning electron microscopy micrographs of Fe3O4MMT NCs with high magnification for 10 and 120 wt (a) and (b)

times2500 SEM10120583m

(a)

times2500 SEM10120583m

(b)

times2500 SEM10120583m

(c)

times2500 SEM10120583m

(d)

Figure 6 The scanning electron microscopy micrographs of MMT (a) and Fe3O4MMT NCs for 50 90 and 120 wt (b) (c) and (d)

to the high density of ion-exchange sites on MMT the highlycharged Fe

3O4-NPs are strongly bound via electrostatic

interaction to the surface The higher abundance of NPsaggregates in the MMT composite is in direct correlationwith the smaller primary NPs dimensions [20]

33 Scanning Electron Microscopy (SEM) SEM images showthat the Fe

3O4-NPs are in spherical shape (Figures 5(a)

and 5(b)) Fe3O4-NPs have very high surface free energy

which lead to instability in their dispersions thermodynamic

system stability is restored upon Ostwald ripening [21] Theisotopic nucleation rate per unit area at the interface betweenthe Fe

3O4-NPs leads to forming the spherical shape NPs

due to equivalent growth rate along every direction of thenucleation as the sphere has the smallest surface area per unitvolume compared to other shapes [22] Figure 6 clearly showsthat the size of Fe

3O4-NPs in 10 wt sample is smaller than

120 wt which is in line with the TEM and XRD resultspreviously mentioned

A general view of the MMT with a typical sheet-likestructure with large flakes can be observed in Figure 6(a)

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

6 Journal of Nanomaterials

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(a)

MMT layer

Fe3O4-NPs

times100000 100nm SEM

(b)

Figure 5 The scanning electron microscopy micrographs of Fe3O4MMT NCs with high magnification for 10 and 120 wt (a) and (b)

times2500 SEM10120583m

(a)

times2500 SEM10120583m

(b)

times2500 SEM10120583m

(c)

times2500 SEM10120583m

(d)

Figure 6 The scanning electron microscopy micrographs of MMT (a) and Fe3O4MMT NCs for 50 90 and 120 wt (b) (c) and (d)

to the high density of ion-exchange sites on MMT the highlycharged Fe

3O4-NPs are strongly bound via electrostatic

interaction to the surface The higher abundance of NPsaggregates in the MMT composite is in direct correlationwith the smaller primary NPs dimensions [20]

33 Scanning Electron Microscopy (SEM) SEM images showthat the Fe

3O4-NPs are in spherical shape (Figures 5(a)

and 5(b)) Fe3O4-NPs have very high surface free energy

which lead to instability in their dispersions thermodynamic

system stability is restored upon Ostwald ripening [21] Theisotopic nucleation rate per unit area at the interface betweenthe Fe

3O4-NPs leads to forming the spherical shape NPs

due to equivalent growth rate along every direction of thenucleation as the sphere has the smallest surface area per unitvolume compared to other shapes [22] Figure 6 clearly showsthat the size of Fe

3O4-NPs in 10 wt sample is smaller than

120 wt which is in line with the TEM and XRD resultspreviously mentioned

A general view of the MMT with a typical sheet-likestructure with large flakes can be observed in Figure 6(a)

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

Journal of Nanomaterials 7

C

NaNa Na

OMg

Al

Si

MMT powder

C

NaNa Na

OOMg

Al

0 1 2 3 4 5 6 7

Energy (keV)

(a)

OMg

AlC

NaNaFeFe

Fe Fe

Si

0 1 2 3 4 5 6 7

Energy (keV)

OMgggg

AllC

NaNaFeFe

Fe Fe

Si

(1 wt)MMTFe3O4 NCs

(b)

CO

FeFe Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

(5 wt)

CO

FeFe Fe

Fe

MgggggAl

Na

Si

MMTFe3O4 NCs

(c)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

0 1 2 3 4 5 6 7

Energy (keV)

C OFe

Fe

Fe

Fe

MgAl

Na

Si

(12 wt)MMTFe3O4 NCs

(d)

Figure 7 Energy dispersive X-ray spectroscopy of MMT (a) and Fe3O4MMT NCs for 10 50 and 120 wt (b) (c) and (d)

and it confirmed that the small difference can be observed inmorphology structure of MMT compared with Fe

3O4MMT

NCs (Figures 6(b)-6(c))The different brightness of theMMTand MMT supported Fe

3O4-NPs and some disordering in

the MMT structure are due to the abundance of iron oxidecoating on the surface of clay

34 EnergyDispersiveX-Ray Spectroscopy (EDX) Theoxygenand iron peaks in EDX spectrum reveal the existence ofFe3O4-NPs (Figure 7) In Figure 7(a) the peaks around 17

27 29 37 40 45 64 and 71 keV are related to the bindingenergies of MMT The peaks around 02 22 64 and 70 keVare related to Fe

3O4-NPs elements respectively in Figures

7(b)ndash7(d) [20] Moreover with an increase amount of ironoxide the iron peaks height increases in the Fe

3O4MMT

NCs (10 50 and 120 wt wt ) Additionally the EDXRFspectra for the MMT and for Fe

3O4MMT NCs confirm the

presence of elemental compounds in the MMT and Fe3O4-

NPs without any impurity peaksThe results indicate that thesynthesized Fe

3O4-NPs are in high purity

35 FTIR Chemical Analysis For pure MMT the bendingmode of Al-Al-OH is found at 910 cmminus1 because of the largeamount of Al in the octahedral site of oxygen and the bendingmode of Si-O-Al was observed at 513 cmminus1 The band at3633 cmminus1 (Figure 8(a)) that identified stretching vibrationof the structural hydroxyl group of MMT was detected [23]Figures 8(b)ndash8(f) show that there were no many changes in

36333390

36183385

36173388

36093420

36093411

3613

4000 3500 3000 2500 2000 5001500 1000 0

3411

1622

1623

1624 1098

1098

1107

1624

1624

992

972

977

977

16221105

506

403

503

375505

398

510371

Tran

smitt

ance

(au

)

Wave number (cmminus1)

(a)

(b)

(c)

(d)

(e)

(f)

Figure 8 FTIR spectra of MMT (a) and Fe3O4MMT NCs (b) (c)

(d) (e) and (f)

the spectra of Fe3O4MMT NCs compared with MMT The

bands between 446 cmminus1 and 625 cmminus1 can be assigned to Fe-O stretching vibration which may be due to the overlappingof Si-O and Al-OH

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

8 Journal of Nanomaterials

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

1210

8

6

4

2

0

minus2

minus4

minus6

minus8

minus10

minus12

(a)

minus25000

minus20000

minus15000

minus10000

minus5000 0

5000

10000

15000

20000

25000

Field (G)

Mom

ent m

ass (

emu

g)

3025201510

50

minus5minus10

minus15minus20minus25minus30

(b)

Figure 9 Magnetization curve of Fe3O4MMT NCs 10 (a) and 120 (b)

The FTIR spectra demonstrated the inflexibility of silicatelayers and nonbond chemical interface between the silicatelayers and Fe

3O4-NPs in Fe

3O4MMT NCs These results

confirmed that with an increase amount of Fe3O4-NPs in

the Fe3O4MMT NCs due to the existence of van der Waals

interactions between the oxygen groups of MMT and Fe3O4-

NPs peak areas shifted to lowwave numbers and the intensityof peaks decreased [16]

36 Vibrating Sample Magnetometer (VSM) The vibratingsample magnetometer (VSM) was applied to test the mag-netic properties of Fe

3O4MMT NCs The magnetization

curves for Fe3O4MMT NCs in 10 and 120 wt are shown

in Figure 9 It can be seen from themagnetization curves thatthe saturation magnetization (Ms) of the Fe

3O4MMT NCs

increased from 1210 to 3240 emugminus1 when Fe3O4content

increased from 10 to 120 wt of composite It indicatedmore Fe

3O4being trapped in the MMT layers

4 Conclusion

In this work we synthesized successfully Fe3O4MMT NCs

through coprecipitation method which is a cheap facile andenvironmental friendly method Sodium hydroxide was usedas reducing agent and ferric chloride and ferrous chloridewere used as the iron precursors These synthesized Fe

3O4-

NPs with high magnetization and good dispersion are on theexternal surface and between the layers of montmorilloniteOur results show that the amount of NaOH (reducing agent)has significant effect on the size of nanoparticles Smallersized nanoparticles were obtained due to more reducingagent amount Moreover these results indicate that mont-morillonite used here can act as an effective support for thesynthesis of magnetic nanoparticles

The specific surface areas of Fe3O4MMTNCswere larger

than pure montmorillonite The comparison between thePXRD patterns of MMT and the prepared Fe

3O4MMT NCs

indicated the immobilized formation of Fe3O4-NPs in the

interlamellar space of the MMT layers The TEM imagesshowed that the mean diameter of the nanoparticles rangedfrom 824 nm to 1288 nm

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors would like to acknowledge the financial supportfrom Universiti Putra Malaysia (UPM) (RUGS Project no9199840)They are also grateful to the staff of theDepartmentof Chemistry UPM and the Institute of Bioscience UPM forthe technical assistance

References

[1] G Mihoc R Ianos C Pacurariu and I Lazau ldquoCombustionsynthesis of some iron oxides used as adsorbents for phenol andp-chlorophenol removal from wastewaterrdquo Journal of ThermalAnalysis and Calorimetry vol 112 no 1 pp 391ndash397 2013

[2] M Abbas B Parvatheeswara Rao S M Naga M Takahashiand C Kim ldquoSynthesis of highmagnetization hydrophilic mag-netite (Fe

3O4) nanoparticles in single reactionmdashsurfactantless

polyol processrdquo Ceramics International vol 39 no 7 pp 7605ndash7611 2013

[3] F Ahangaran A Hassanzadeh and S Nouri ldquoSurface modifi-cation of Fe

3O4SiO

2microsphere by silane coupling agentrdquo

International Nano Letters vol 3 no 1 pp 1ndash5 2013[4] N Wang L Zhu D Wang M Wang Z Lin and H Tang

ldquoSono-assisted preparation of highly-efficient peroxidase-likeFe3O4magnetic nanoparticles for catalytic removal of organic

pollutants with H2O2rdquo Ultrasonics Sonochemistry vol 17 no 3

pp 526ndash533 2010[5] K Raja S Verma S Karmakar S Kar S J Das and K S Bart-

wal ldquoSynthesis and characterization ofmagnetite nanocrystalsrdquoCrystal Research and Technology vol 46 no 5 pp 497ndash5002011

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

Journal of Nanomaterials 9

[6] S Ahmadi C-H Chia S Zakaria K Saeedfar and NAsim ldquoSynthesis of Fe

3O4nanocrystals using hydrothermal

approachrdquo Journal of Magnetism and Magnetic Materials vol324 no 24 pp 4147ndash4150 2012

[7] G Gao R Shi W Qin et al ldquoSolvothermal synthesis and char-acterization of size-controlled monodisperse Fe

3O4nanoparti-

clesrdquo Journal of Materials Science vol 45 no 13 pp 3483ndash34892010

[8] G Li Z Zhao J Liu and G Jiang ldquoEffective heavy metalremoval fromaqueous systems by thiol functionalizedmagneticmesoporous silicardquo Journal of Hazardous Materials vol 192 no1 pp 277ndash283 2011

[9] I Larraza M Lopez-Gonzalez T Corrales and GMarcelo ldquoHybrid materials magnetite-polyethylenimine-montmorillonite as magnetic adsorbents for Cr(VI) watertreatmentrdquo Journal of Colloid and Interface Science vol 385 no1 pp 24ndash33 2012

[10] B C Munoz G W Adams V T Ngo and J R Kitchin ldquoStablemagnetorheological fluidsrdquo Google Patents 2001

[11] A K Mishra S Allauddin R Narayan T M Aminabhaviand K V S N Raju ldquoCharacterization of surface-modifiedmontmorillonite nanocompositesrdquo Ceramics International vol38 no 2 pp 929ndash934 2012

[12] M Fan P Yuan J Zhu et al ldquoCore-shell structured ironnanoparticles well dispersed on montmorilloniterdquo Journal ofMagnetism and Magnetic Materials vol 321 no 20 pp 3515ndash3519 2009

[13] A K Gupta and M Gupta ldquoSynthesis and surface engineeringof iron oxide nanoparticles for biomedical applicationsrdquoBioma-terials vol 26 no 18 pp 3995ndash4021 2005

[14] M Zhang G Pan D Zhao and G He ldquoXAFS study of starch-stabilized magnetite nanoparticles and surface speciation ofarsenaterdquo Environmental Pollution vol 159 no 12 pp 3509ndash3514 2011

[15] S Li P Wu H Li et al ldquoSynthesis and characteriza-tion of organo-montmorillonite supported iron nanoparticlesrdquoApplied Clay Science vol 50 no 3 pp 330ndash336 2010

[16] K ShameliM BAhmadMZargarWMZWYunus A Rus-taiyan and N A Ibrahim ldquoSynthesis of silver nanoparticles inmontmorillonite and their antibacterial behaviorrdquo InternationalJournal of Nanomedicine vol 6 pp 581ndash590 2011

[17] K Kalantari M B Ahmad K Shameli and R Khandan-lou ldquoSynthesis of talcFe

3O4magnetic nanocomposites using

chemical co-precipitation methodrdquo International Journal ofNanomedicine vol 8 pp 1817ndash1823 2013

[18] H Maleki A Simchi M Imani and B F O Costa ldquoSize-controlled synthesis of superparamagnetic iron oxide nanopar-ticles and their surface coating by gold for biomedical applica-tionsrdquo Journal of Magnetism and Magnetic Materials vol 324no 23 pp 3997ndash4005 2012

[19] H Yan J Zhang C You Z Song B Yu and Y ShenldquoInfluences of different synthesis conditions on properties ofFe3O4nanoparticlesrdquoMaterials Chemistry and Physics vol 113

no 1 pp 46ndash52 2009[20] T Szabo A Bakandritsos V Tzitzios et al ldquoMagnetic iron

oxideclay composites effect of the layer silicate support onthe microstructure and phase formation of magnetic nanopar-ticlesrdquo Nanotechnology vol 18 no 28 Article ID 285602 2007

[21] S Hribernik M Sfiligoj-Smole M Bele S Gyergyek J Jamnikand K Stana-Kleinschek ldquoSynthesis of magnetic iron oxideparticles development of an in situ coating procedure for

fibrous materialsrdquo Colloids and Surfaces A Physicochemical andEngineering Aspects vol 400 pp 58ndash66 2012

[22] DK KimMMikhaylova Y Zhang andMMuhammed ldquoPro-tective coating of superparamagnetic iron oxide nanoparticlesrdquoChemistry of Materials vol 15 no 8 pp 1617ndash1627 2003

[23] Y H Son J K Lee Y Soong D Martello and M ChyuldquoStructure-property correlation in iron oxide nanoparticle-clayhybrid materialsrdquo Chemistry of Materials vol 22 no 7 pp2226ndash2232 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CeramicsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CompositesJournal of

NanoparticlesJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

Biomaterials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MetallurgyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

MaterialsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Nano

materials

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofNanomaterials