research article effect of hydrogen peroxide content on the ...research article effect of hydrogen...

Research ArticleEffect of Hydrogen Peroxide Content onthe Preparation of Peroxotitanate Materials forthe Treatment of Radioactive Wastewater

Wein-Duo Yang1 Chau Thanh Nam1 Jen-Chien Chung2 and Hsin-Ya Huang1

1Department of Chemical and Materials Engineering National Kaohsiung University of Applied Sciences415 Chien-Kung Road Kaohsiung 807 Taiwan2Chemical Engineering Division Institute of Nuclear Energy Research Longtan Taoyuan 325 Taiwan

Correspondence should be addressed to Wein-Duo Yang ywdkuasedutw

Received 21 July 2016 Accepted 28 September 2016

Academic Editor Silvia Licoccia

Copyright copy 2016 Wein-Duo Yang et alThis is an open access article distributed under theCreative CommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Themodification of peroxotitanate using hydrogen peroxide significantly improved the ion-exchange capacity of titanate materialsas sorbents for metal ions contained in a radioactive waste simulant solution The effects of hydrogen peroxide content (hydrogenperoxidetitanium isopropoxide molar ratios hereafter expressed as HT) on the properties of as-prepared titanate synthesized at130∘C and at pH of 6-7 followed by freeze-drying were investigatedThe peroxotitanate materials thus obtained were characterizedby XRD BET SEM TEM EDX ICP and Raman spectroscopy At an HT ratio of 2 peroxotitanate predominantly exhibited anamorphous structure with a clearly observed tubular or fibrous structure Furthermore peroxotitanate modified at an HT ratio of2 exhibited the best ion-exchange capacity of 191mg gminus1 for metal ions contained in a radioactive waste simulant solution Hencethese peroxotitanate materials are suitable for removing metal ions from wastewater especially lanthanide ions (Ln3+) and Sr2+

1 Introduction

Heavy metals and radioactive waste are not biodegradableor destructible and can persist in the natural environmentwhich in turn indirectly affect human health Currentlychemical precipitation ion exchange reverse osmosis mem-brane filtration and heavymetal adsorption are employed forthe treatment of precious-metal-containingwastewater [1ndash3]

Derived sodium titanate exhibits high selectivity forseveral metal ions in both acidic and alkaline waste solutionsincluding those containing strontium and several actinides[4 5] In recent years researchers have investigated the useof derived sodium titanate as adsorbent materials for metalions which is the baseline material for the removal of 90Srand alpha-emitting radionuclides [6 7]

Previously several studies have investigated and reportedthe synthesis of various forms of titanate materials such astitanate nanofibers hydrogen titanate nanowires and titanatenanostructures [8ndash10] The most common chemical formulafor the sodium titanate crystal is Na

2TinO2n+1 (119899 = 3 or

6) the structure with 119899 = 3 is more common as (Ti3O7)2

minus

and Na+ bind together affording a layered structure Thesodium matrix Na

2Ti3O7is reported to exhibit the highest

ion-exchange capacity [11] On the other hand depending onthe extent of exchange between sodium and protons chemi-cal formulae of Na

2Ti3O7sdotnH2O Na

2minus119909H119909Ti3O7sdotnH2O and

H2Ti3O7sdotnH2O have been proposed for titanate nanotubes

[12]The mechanism of the adsorption of lanthanide ions

(Ln3+) on sodium trititanate nanofibers is believed to occuras follows Na+ occupies the space between the interlayersparallel to the crystal axis followed by the exchange of Na+with Ln3+ When Ln3+ enters the structure a stable three-dimensional crystal structure of Ln3+-titanate salts is formedfollowed by the removal of Ln3+ [13] Trititanate nanofibersexhibit very good and unique properties with respect to theion exchange and adsorption of lanthanide metals attributedto the number of Na+ or H+ between the layers

Nyman and Hobbs have investigated a series of peroxoti-tanates by the addition of hydrogen peroxide which results

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2016 Article ID 9540529 9 pageshttpdxdoiorg10115520169540529

2 Journal of Nanomaterials

in the significant improvement of the sorption ability forstrontium and actinides [14] Furthermore peroxotitanatesorbents prepared via modification with hydrogen peroxideare more superior to titanates prepared without hydrogenperoxide [15] Titanate materials that are synthesized inthe presence of H

2O2and undergo modified postsynthesis

of sodium titanate with H2O2demonstrate good radionu-

clide sorption selectivity kinetics and capacity [7 16] Amethodology to modify the synthesis of sodium titanate forproducing materials which achieve significantly improvedstrontium and actinide removal and increased capacity andsorption kinetics was proposed in an earlier study [17]However to the best of our knowledge studies on the effectof hydrogen peroxide content on as-prepared peroxotitanatematerials for the treatment of radioactive wastewater haveseldom been reported

In this study peroxo-modified sodium titanate was pre-pared by the hydrothermal method using hydrogen peroxideat different titaniumhydrogen peroxide molar ratios Effectsof different titaniumhydrogen peroxide molar ratios on theproperties of peroxotitanate materials were determined Thehigh adsorption efficiency of peroxotitanate for the treatmentof stimulant wastewater was confirmed

2 Experimental

21 Reagents Analytical-grade chemicals were used asreceived without any further purification Ti(O-iC

3H7)4

(98 purity Fluka) NaOH (ge96 purity Showa) HNO3

(65 purity Showa) NaNO2(985 purity Showa) H

2O2

(35 purity HSE) and lanthanide metal (Merck 99) wereused for ion-exchange experiments with compounds such asSr(NO

3)2 Co(NO

3)2sdot6H2O Nd(NO

3)3sdot6H2O Sm(NO

3)3sdot

6H2O Eu(NO

3)3sdot6H2O Ce(NO

3)3sdot6H2O Gd(NO

3)3sdot6H2O

Y(NO3)3sdot6H2O La(NO

3)3sdot6H2O and ultrapure water

(purity ge 98)

22 Preparation of Peroxotitanate Materials Figure 1 showsthe flowchart of the synthesis of peroxotitanate materialsFirst 06 g of NaNO

2was dissolved in 100mL of 01MHNO

3

and added to a vessel Second Ti(O-iC3H7)4was slowly

added to an acetic acid solution which was stirred usinga magnetic stirrer for 30min and heated to 130∘C in anautoclave for 3 h Third NaOH was slowly added to thevessel using a reflux condenser for achieving pH of 6-7 Afteruniform stirring a white precipitate was observed and thenan appropriate amount of H

2O2was added to the system

The titanate rapidly formed from the titanium precipitatePeroxotitanate materials were also synthesized at varioushydrogen peroxideTi(O-iC

3H7)4molar ratios (HT molar

ratios)The solution gradually became transparent and brightyellow further forming a yellow peroxotitanate precipitateAfter the reaction was complete the precipitates were cooledand washed several times with DI water until the pH reachedapproximately 7 Finally the resulting precipitate was freeze-dried (lt01 torr and minus45∘C) followed by grinding affordingperoxo-modified titanate material Table 1 summarizes theHT molar ratios utilized for the synthesis of peroxotitanateunder different experimental conditions

Table 1Molar ratios of hydrogen peroxide and titanium isopropox-ide utilized for the synthesis of peroxotitanate materials underdifferent experimental conditions

Sample Reaction temp (∘C) pH Drying Ti H2O2

H1 130 6-7 F 1 1H2 130 6-7 F 1 2H3 130 6-7 F 1 3H4 130 6-7 F 1 4

Yellow precipitate

Suction filtration

Nanofiber

Treatment with DI water

Freeze-drying

TIPT + acetic acid

pH = 6sim7Stirring

H2O2

NaNO2 + HNO3

NaOH

Stirring for 3 h at 1130∘C

Figure 1 Flowchart of the synthesis of peroxotitanate materials bythe hydrothermal method

23 Instrumentation The glassware used for the experi-ments was soaked in concentrated HNO

3for 12 h and then

thoroughly washed using tap water and double-distilledwater followed by drying overnight in a hot-air oven at50∘C The crystal structures of the samples obtained wereinvestigated by X-ray diffraction (XRD PANalytical XrsquoPertPRO XRD CuK

120572radiation) and micro-Raman spectroscopy

(Dimension-P2 Raman) A Micromeritics ASAP 2020 ana-lyzer was employed for BET analysis TEMmeasurement wasperformed using a CM-200 TEM system (Philips) operatingat 200 kV Before TEM analysis the samples were sonicatedin ethanol for 15min followed by the deposition of 2-3 dropsof the sample on a thin carbon film supported on a perforatedcopper grid the samples were then dried overnight at 60∘CFourier transform infrared (FTIR) spectra were recorded ona spectrometer (Perkin Elmer) UV-vis diffuse reflectancespectra were recorded between 300 and 800 nm on a Jasco V-600 UV-vis spectrophotometer which was employed tomea-sure the red shift in samples All absorbance measurementswere recorded on a UV-vis spectrophotometer (Hitachi U-2800) equipped with a quartz cell of 1 cm Thermogravime-trydifferential thermal analysis (TGADTA) was performed

Journal of Nanomaterials 3

in air on a TA SDT-Q600 instrument using 8ndash10mg ofpowder at a heating rate of 10∘min and a maximum temper-ature of 800∘C The composition of elements in the sampleswas investigated by energy-dispersive X-ray spectrometry(EDS) (Philips XL-40) Inductively coupled plasma-atomicemission spectroscopy (ICP-AES Perkin Elmer ELAN 6000)was employed for the detection of trace metals

24 Adsorption of Metal Ions on Peroxotitanate MaterialsThe radioactive waste simulant solution at pH 5-6 providedby the Institute of Nuclear Energy Research in Taiwancontained an initial concentration of 50 ppm for each of Ce2+Co2+ Eu2+ Gd3+ La3+ Nd3+ Sm3+ Sr3+ Sr2+ Y3+ and otheranions

First the as-prepared peroxotitanate was added to theradioactive waste simulant solution for permitting ionexchange which removed metal ions Second 100mL of thesimulant solution was added to a 250mL beaker and stirredat room temperature The resultant solution was subjected toanalysis for determining the relationship between adsorptiontime and efficiency

In experiments 005 g of the as-prepared peroxotitanatematerial was dispersed in 100mL of the radioactive wastesimulant solution followed by stirring at room temperatureand atmospheric pressure After every 15min the solutionwas tested for the presence of metal ions by ICP-AES fordetermining the ion-exchange capacity of the as-preparedperoxotitanate materials Furthermore surface analyses ofthe as-prepared titanates were performed using a VGInstruments X-ray photoelectron spectrometer (XPS) Theadventitious C 1s signal at 2846 eV was used to calibrate thecharge-shifted energy scale

3 Results and Discussion

31 Characterization of the As-Prepared Peroxotitanate Mate-rials XRD patterns of the as-prepared peroxotitanate mate-rials synthesized at different calcination temperatures at anHT ratio of 2 are shown in Figure 2 The as-preparedperoxotitanate exhibitingweak diffraction peak is amorphousand poorly crystalline The powder was still amorphous ifcalcined at temperature below 500∘C but the powder hasa trace of anatase at 600∘C However the sample calcinedat 700∘C exhibited characteristic peaks 2120579 at around 284∘and 475∘ which are attributed to Na

119909H2minus119909

Ti3O7structure

with the crystal diffraction plane of (111) and (020) respec-tively (JCPDS 31-1329) Nevertheless the powder is alsoaccompanied with few TiO

2(rutile phase) Furthermore the

diffraction peaks are observed at 2120579 = 118 141 245 and 301(JCPDS 73-1398) These are attributed to the Na

119909H2minus119909

Ti6O13

structure of diffraction crystal plane peaks of (200) (201)(110) and (203) respectively The XRD studies were in goodagreement with the previous studies [18] Kim et al [19]reported Raman spectra of the titanate powders with Nacontent (NaH-Ti Nanotube) taken at temperature of 700∘Cfor 3 hours in airThey also showed that it is amixture of H-TiNanotube Na

2Ti3O7 Na2Ti6O13 and TiO

2(anatase)

lowastlowast lowast

lowastlowast

lowast

As-prepared

AnataseRutile

900∘C

800∘C

700∘C

600∘C

500∘C

400∘C

10 15 20 25 30 35 40 45 50 555 602120579 (degree)

Inte

nsity

(arb

itrar

y un

its)

NaHTi3O7

NaHTi6O13

lowast

Δ

ΔΔ

Δ

loz

Figure 2 XRD pattern of the as-prepared peroxotitanate materialssynthesized at different calcination temperatures at an HT ratio of2

When the calcination temperatures were at 900∘C mostof the Na

119909H2minus119909

Ti3O7structure peaks disappear and other

diffraction peaks of the NaxH2minusxTi6O13 structure were exam-ined

Furthermore in this study the authors used titanium iso-propanoxide as raw material These peroxotitanates includedNaxH2minusxTi3O7 that may transform to TiO

2in high tem-

perature Also the synthesis is entirely different from con-ventional titanate synthesis using TiO

2powder in NaOH

atmosphere Nyman and Hobbs [14] indicated that titaniumisopropanoxide reacts with methanol in sodium hydroxidesolution to become monosodium titanate shown as follows

2Ti (OC3H7)4+NaOCH

3+ 5H2O

997888rarr NaHTi2O5+ CH

3OH + 8C

3H7OH

(1)

Figure 3 shows the Raman spectra for the peroxotitanatesprepared at various H

2O2titanium molar ratios As seen

from this figure these broadened peaks of titanates indicatethat the crystallinity is low in accordance with the XRDmeasurements (not shown) The Raman spectra of the as-prepared materials have the bands characteristic around 285455 710 and 910 cmminus1 which are identified to be titanatephase [20] Furthermore Raman spectra of the titanatesprepared at HT ratios of 2 and 3 ((c) and (d) in Figure 3) havea broader band in the range of 600ndash720 cmminus1 than the Ramanspectra of the titanate obtained at lower HT ratios of 0 and 1((a) or (b) in Figure 3) It can be explained that the titanatesprepared at higher HT ratios contain a higher fraction ofH-Ti-NT structure Therefore the greater broadening of theRaman bands in H-Ti-NTmay be related to the greater watercontent in these titanate materials [21]

Typically the Raman shifts for titanate obtained at HTratio of 2 were 153 185 269 283 386 450 693 and828 cmminus1 ((c) in Figure 3) The observed Raman shifts arein good agreement with those reported by Korosi et alfor H

2Ti2O5sdotH2O [20] However the three most intense


(b)

(a)

Inte

nsity

(au

)(d)

(c)

200 300 400 500 600 700 800 900100 1000Raman shift (cmminus1)

Figure 3 Raman spectra of sodium titanates prepared at differenthydrogen peroxide molar ratios (a) HT ratio of 0 (b) HT ratio of1 (c) HT ratio of 2 and (d) HT ratio of 3

bands at 269 283 and 450 cmminus1 are also characteristic ofNaxH2minusxTi3O7sdotH2O

Figure 4 shows the nitrogen adsorption-desorptionisotherms of the sodium titanate synthesized before andafter modification using hydrogen peroxide As per BDDTclassification all samples exhibit type IIb isotherms withH3-type hysteresis loops with no indication of a plateau athigh 119875119875

0[20 21] The inset of Figure 4 shows the pore

size distribution of all samples the sample with no addedhydrogen peroxide (Figure 4(a)) exhibits a wider pore sizedistribution (approximately 10ndash60 A) while that preparedat an HT ratio of 2 exhibits a relatively narrow pore sizedistribution (approximately 10ndash40 A)

The pore size distribution of nanotubes (HT = 2) at 10ndash100 nm is narrower than that without peroxide (HT = 0)Owing to the decomposition of peroxotitanate during theprocess of adding hydrogen peroxide therefore it exhibitsless aggregation of the nanotubes demonstrating a moreuniform distribution of pore sizes This is consistent withthe studies of Kim et al who considered the morphologicalexamination of the nanotubes where the smaller pores(lt10 nm) may correspond to the pores inside the nanotubesand the diameters of these pores are equal to the innerdiameter of the nanotubes while the larger pore (10ndash100 nm)can be attributed to the aggregation of the nanotubes [19]Hence the titanate prepared by adding hydrogen peroxideproduces a more uniform pore size distribution

Table 2 and Figure 5 show the results obtained for specificsurface area pore volume and average pore diameter Withincreasing H

2O2Ti molar ratio the specific surface area

gradually decreases reaching theminimumat anHT ratio of2 With further increase in the HT ratio the specific surfacearea slightly increases

Table 2 BET analysis of peroxotitanatematerials synthesized at dif-ferentmolar ratios of hydrogen peroxide and titanium isopropoxide

Properties SBET (m2g) Pore volume

(cm3g)Average pore size

(A)HT = 0 1237 056 183HT = 1 468 022 190HT = 2 218 011 206HT = 3 364 019 206HT = 4 381 020 210

Figure 5 shows the TEM images of the titanates syn-thesized at different molar ratios of hydrogen peroxide andtitanium isopropoxide At an HT ratio of 1 (Figure 5(a))the tubular or fibrous structure is not clear On the otherhand with increasing hydrogen peroxide content (HT =2) the tubular or fibrous structures with a diameter ofapproximately 10 nm are clearly observed As can be observedin Figure 5(d) another nanostructure predominates overthe nanotubes or nanofibers apparently nanosheets possiblyexplaining the increase in surface area (at similar dimen-sions nanosheets exhibit a surface area greater than thatof nanotubes or nanofibers) Furthermore with increasinghydrogen peroxide content the density of nanotubular ornanofibrous structures tends to increase attributed to theaddition of excess hydrogen peroxide which makes thereaction more intense hence binding with O

2between the

crystal layers is accelerated prevailing in the formation ofnanosheet structures

Figure 6 shows the SEM images of the peroxotitanatematerials prepared at anHT ratio of 2 at different calcinationtemperatures At a calcination temperature of 600∘C thesample nanostructure still retains the tubular or fibrous formand is clearly observed However with increasing calcinationtemperature to 700∘C rod-like nanotubes or nanofiberscoexist Moreover from 700∘C the nanotubes or nanofibersdecrease attributed to their condensed tunnel structure andNa2Ti6O13

exhibits an ion-exchange capacity significantlyless than that of its counterpart with an open layered structure[15] At 800∘C because of the high-temperature effect thesample exhibits a short rod-like structure the diameter ofwhich increases with calcination temperature

The sodium ion content was measured by EDS The spe-cific surface area (Table 2) and content of sodium ion in thesamples are combined to construct a correlogram betweenspecific surface area content of sodium ion in peroxotitanatematerials and different hydrogen peroxide and titaniumisopropoxide molar ratios as shown in Figure 7 At an HTratio of 0 (sample notmodified byH

2O2) the sample exhibits

the highest specific surface area of 1237m2g and the lowestsodium content of 54 Moreover with increasing hydrogenperoxide content specific surface area decreases and sodiumcontent increases gradually In fact at an HT ratio of 2 thesample exhibits the lowest specific surface area of 218m2gand the highest sodium content of 73With further increasein the hydrogen peroxide content the content of sodium inthe titanates gradually decreases attributed to the fact that


AdsorptionDesorption

Pore

vol

ume (

mm3gmiddotn

m)

20 40 60 80 100 1200Pore diameter (nm)

02 04 06 08 1000

02468

101214

0

5

10

15

20

25

Volu

me a

dsor

bed

(cm3g

STP

)

Relative pressure (PP0)

(a)


0

Pore

vol

ume (

mm3gmiddotn

m)

0

1

2

3

4

5

Volu

me a

dsor

bed

(cm3g

STP

)

00

05

10

15

20

25

40 60 80 100 12020Pore diameter (nm)

02 04 06 08 1000Relative pressure (PP0)

(b)

Figure 4 Nitrogen adsorption-desorption isotherms of sodium titanate materials synthesized before and after modification by hydrogenperoxide (a) HT ratio of 0 and (b) HT ratio of 2

(a) (b)

(c) (d)

Figure 5 TEM images of the peroxotitanates prepared at different hydrogen peroxide and titanium isopropoxide (HT) molar ratios of (a) 1(b) 2 (c) 3 and (d) 4


900∘C800

∘C700∘C600

∘C

500∘C400

∘C300∘C200

∘C

Figure 6 SEM images of peroxotitanate materials prepared at HT ratios of 2 at different calcination temperatures

Na a

tom

ic p

erce

nt (

)

381364218

468

1237

64

71

58

54

50

55

60

65

70

75

BET

surfa

ce ar

ea (m

2g

)

20

40

60

80

100

120

140

73

HT = 0 HT = 1 HT = 3 HT = 4HT = 2

Figure 7 Correlogram for the hydrogen peroxide and titaniumisopropoxide molar ratio specific surface area and content ofsodium ions in the as-prepared peroxotitanates

modification with hydrogen peroxide leads to an increasein the number of oxygen-containing functional groups onthe surface and also improves the protonation of the surfacehence the substitution of Na+ by H+ increases which in turnresults in the reduction of sodium contentTheHT ratio of 2is possibly the optimal amount that permits coprecipitationhence the sodium content is optimal in the layered structureof the peroxotitanate materials

The atomic ratiosmeasured by XPSwere utilized to revealthe surface properties of the as-prepared peroxotitanateTable 3 shows TiO atomic ratios by XPS of the peroxotitanateprepared at different HT molar ratios From this table theTiO molar ratio decreases as the HT ratio increases up to 2and then slightly increases as the HT ratio increases above2 during the synthesis of peroxotitanate The attacking offunctional groups containing O

2

2minus HOOminus or H2O2 and so

Table 3 Atomic ratios by XPS of the peroxotitanate prepared atdifferent HT molar ratios

Sample Atomic percentage ()Ti O Na C Ti O (atomic ratio)

HT = 0 195 552 55 195 1 283HT = 1 187 556 67 190 1 297HT = 2 171 582 76 171 1 340HT = 3 181 568 73 178 1 314HT = 4 183 572 70 175 1 313

forth to form a Ti-peroxospecies is explained therefore theas-prepared peroxotitanate contains a relative higher fractionof oxygen on the surface

32 Adsorption of Metal Ions Contained in the RadioactiveWaste Simulant Solution First 100mL of the radioactivewaste simulant solution with an initial concentration of50 ppm of each of Ce2+ Co2+ Eu2+ Gd3+ La3+ Nd3+ Sm3+Sr2+ andY3+ was provided by the Institute ofNuclear EnergyResearch (Taiwan) ICP-AES was employed to analyze theconcentration of these metal ions Ion-exchange capacityis calculated using formula (1) for determining adsorptioncapacity ion-exchange capacity(mgg) = (119862

1minus1198622)times (119881119882)

1198621is the initial concentration (ppm) 119862

2is the concentration

after adsorption (ppm) 119881 is solution volume (L) and 119882 isthe adsorbent weight (g)

The peroxotitanate materials prepared at different molarratios of hydrogen peroxide and titanium isopropoxide weretested for the adsorption of the metal ions contained inthe simulant solution Figure 8 plots ion-exchange capacityversus time Treatment with hydrogen peroxide during syn-thesis results in the attack of the titanate by different oxygen-containing functional groups (eg peroxoligand can exist asO2

2minus HOOminus or H2O2) in the surface structure affording a


0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2

Figure 8 Plot of ion-exchange capacity versus time for the as-prepared peroxotitanate materials prepared at different hydrogenperoxide molar ratios

peroxomodified sodium titanate complex in the presence ofa protonated or hydrated Ti-peroxospecies [22] Generallythis aforementioned species is expressed by the followingchemical formulaHVNa119908Ti2O5sdot(xH2O)[yH119911O2] ((V+119908) = 2119911 = 0ndash2) [23] Hence more negative charges are presenton the surface structure which contribute to the significantincrease in ion exchange with metal ions by electrostaticattractionThe lowest ion-exchange capacity is about 40mggafter 45min for the titanate obtained at an HT ratio of 0without the treatment of hydrogen peroxide because thestructures are newly formed and short (by TEM not shown)making it less attractive to Na+ On the other hand thehighest ion-exchange capacity is observed at an HT ratio of2 (191mgg after 45min) followed by gradual decrease withfurther increase in the hydrogen peroxide content As shownin Figure 7 an HT ratio of 2 affords the highest sodiumcontent

Figure 9 shows the comparison of the ion-exchangecapacities of peroxotitanate materials prepared at an HTratio of 2 for various metal ions The results indicated thatthe as-prepared peroxotitanate material exhibits the best ion-exchange capacity for Nd3+ and the lowest ion-exchangecapacity for Co2+

Figure 10 plots the ion-exchange capacities for metalions contained in the radioactive waste simulant solutionusing peroxotitanate synthesized at an HT ratio of 2 atdifferent calcination temperatures The result indicated thatthe ion-exchange capacity decreases with increasing calcina-tion temperature At high calcination temperatures of 800∘Cand 900∘C the ion-exchange capacity significantly decreasesAt calcination temperatures of 300∘C and 900∘C the high-est and lowest ion-exchange capacities of 1044mgg and493mgg respectively are observed At high temperatures

0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)

Figure 9 Removal efficiencies for different lanthanide metal ionsby the as-prepared peroxotitanate materials synthesized at an HTratio of 2

20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C

Figure 10 Plot of ion-exchange capacities of the as-preparedperoxotitanate materials synthesized at an HT ratio of 2 at differentcalcination temperatures for various metal ions

the morphological structures of the as-prepared peroxoti-tanate possibly change as a result heat stress and aggregationare observed Eventually Na

2Ti3O7is transformed into the

nanorod Na2Ti6O13

structure as previously shown (see theXRD pattern in Figure 2 and the SEM image in Figure 6)which results in the decrease of ion-exchange capacity

Nyman and Hobbs [14 23] developed peroxide modifiedsodium titanates to improve the sorption capacities fornuclear waste treatment Peroxotitanates show remarkableand universal improved sorption behavior with respect toseparation of actinides and strontium from Savannah RiverSite (SRS) nuclear waste simulants They also indicated thatthe enhancement in sorption kinetics can potentially resultin as much as an order of magnitude increase in batchprocessing throughput


However in this study similar peroxotitanate materialswere prepared by the postperoxide adding process Themodification by HT ratio of 2 can enhance the ion-exchangecapacity 4sim5 times more than without the peroxide Per-haps further enhancement of sorption performance will beachieved by processing storing and utilizing the peroxoti-tanate as aqueous slurry rather than as a dry powder whichwill be explored in the future [23]

4 Conclusions

In this study peroxotitanate nanomaterials are synthesized bythe hydrothermalmethod at 130∘C and pH of 6-7 followed bymodificationwith differentmolar ratios of hydrogen peroxideand titanium isopropoxide In addition the properties of theas-prepared peroxotitanate materials are characterized

The structure of the as-prepared peroxotitanate is foundto be amorphous By calcination at 700∘C it is a mixture ofH-Ti nanotube Na


2 With the

calcination temperature of 900∘C most of the NaxH2minusxTi3O7structure peaks disappear and convert to NaxH2minusxTi6O13structure

At an HT ratio of 1 peroxotitanate does not exhibit atubular or fibrous structure however at an HT ratio of 2the tufts of nanostructures with a diameter and length ofapproximately 10 nm are clearly observed With increasinghydrogen peroxide content the nanofiber length decreasesMoreover at anHT ratio of 2 the sample exhibits a relativelynarrow pore size distribution (approximately 10ndash40 A) andthe smallest specific surface area of 218m2g

Modification with hydrogen peroxide significantly in-creases the ion-exchange capacity of the peroxotitanatematerials for metal ions The as-prepared peroxotitanatesynthesized at 130∘C and at pH of 6-7 followed by freeze-drying and modification with HT at a molar ratio of 2exhibits the best ion-exchange capacity of 191mgg for metalions Hence these peroxotitanate materials are suitable forremoving metal ions from wastewater especially lanthanideions (Ln3+)

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

The authors would like to thank the Ministry of Science andTechnology of Taiwan for financial support (Grant noMOST103-2221-E-151-055) as well as Professor John L FalconerDepartment of Chemical and Biological Engineering Uni-versity of Colorado Boulder for important discussions andcomments

References

[1] J G Dean F L Bosqui and K H Lanouette ldquoRemovingheavy metals from waste waterrdquo Environmental Science andTechnology vol 6 no 6 pp 518ndash522 1972

[2] J W Patterson Industrial Wastewater Treatment TechnologyButterworth Publishers Boston Mass USA 1985

[3] S S Ahluwalia and D Goyal ldquoMicrobial and plant derivedbiomass for removal of heavy metals from wastewaterrdquo Biore-source Technology vol 98 no 12 pp 2243ndash2257 2007

[4] R Lynch R Dosch B Kenna J Johnstone and E NowakldquoSandia solidification process a broad range aqueous wastesolidification methodrdquo in Proceedings of the IAEA Symposiumon the Management of Radioactive Waste pp 360ndash372 ViennaAustria 1976

[5] ldquoSandia solidifcation process cumulative reportrdquo Tech RepSAND-76- 0105 Sandia Laboratories Albuquerque NM USAEdited by R W Lynch 1976

[6] R G Dosch ldquoSandia Laboratories technical capabilities auxil-iary capabilitiesrdquo Tech Rep SAND-78-0710 Sandia Laborato-ries Albuquerque NM USA 1978

[7] D Yang Z Zheng H Liu et al ldquoLayered titanate nanofibers asefficient adsorbents for removal of toxic radioactive and heavymetal ions fromwaterrdquo Journal of Physical Chemistry C vol 112no 42 pp 16275ndash16280 2008

[8] H Y Zhu Y Lan X P Gao et al ldquoPhase transition betweennanostructures of titanate and titaniumdioxides via simplewet-chemical reactionsrdquo Journal of the American Chemical Societyvol 127 no 18 pp 6730ndash6736 2005

[9] FWu ZWang X Li andH Guo ldquoHydrogen titanate and TiO2

nanowires as anode materials for lithium-ion batteriesrdquo Journalof Materials Chemistry vol 21 pp 12675ndash12681 2011

[10] E K Ylhainen M R Nunes A J Silvestre and O C MonteiroldquoSynthesis of titanate nanostructures using amorphous precur-sor material and their adsorptionphotocatalytic propertiesrdquoJournal of Materials Science vol 47 no 10 pp 4305ndash4312 2012

[11] V D A Cardoso A G D Souza P P C Sartoratto and LM Nunes ldquoThe ionic exchange process of cobalt nickel andcopper(II) in alkaline and acid-layered titanatesrdquo Colloids andSurfaces A Physicochemical and Engineering Aspects vol 248no 1ndash3 pp 145ndash149 2004

[12] M Qamar C R Yoon H J Oh et al ldquoPreparation andphotocatalytic activity of nanotubes obtained from titaniumdioxiderdquo Catalysis Today vol 131 no 1ndash4 pp 3ndash14 2008

[13] W-D Yang C T Nam Z-J Chung and H-Y Huang ldquoSyn-thesis and metal ion sorption properties of peroxide-modifiedsodium titanate materials using a coprecipitation methodrdquoSurface and Coatings Technology vol 271 pp 57ndash62 2015

[14] M D Nyman and D T Hobbs United states patent 74946402009

[15] B Erjavec R Kaplan and A Pintar ldquoEffects of heat and perox-ide treatment on photocatalytic activity of titanate nanotubesrdquoCatalysis Today vol 241 pp 15ndash24 2015

[16] J Yang D Li H Wang X Wang X Yang and L Lu ldquoEffectof particle size of starting material TiO

2on morphology and

properties of layered titanatesrdquoMaterials Letters vol 50 no 4pp 230ndash234 2001

[17] D T Hobbs M Nyman and A Clearfield ldquoTailoring inorganicsorbents for SRS strontium and actinide separations optimizedmonosodium titanate and pharmacosiderite volume 1rdquo Tech-nical Proposal WSRC-SRTC-PR-02-21-02 2003

[18] R A Zarate S Fuentes J P Wiff V M Fuenzalida andA L Cabrera ldquoChemical composition and phase identifica-tion of sodium titanate nanostructures grown from titania byhydrothermal processingrdquo Journal of Physics and Chemistry ofSolids vol 68 no 4 pp 628ndash637 2007


[19] S-J Kim Y-U Yun H-J Oh et al ldquoCharacterization ofhydrothermally prepared titanate nanotube powders by ambi-ent and in situ Raman spectroscopyrdquo Journal of Physical Chem-istry Letters vol 1 no 1 pp 130ndash135 2010

[20] L Korosi S Papp E Csapo V Meynen P Cool and I DekanyldquoA short solid-state synthesis leading to titanate compoundswith porous structure andnanosheetmorphologyrdquoMicroporousand Mesoporous Materials vol 147 no 1 pp 53ndash58 2012

[21] L Korosi S Papp V Hornok et al ldquoTitanate nanotube thinfilms with enhanced thermal stability and high-transparencyprepared from additive-free solsrdquo Journal of Solid State Chem-istry vol 192 pp 342ndash350 2012

[22] J Luo Q Chen and X Dong ldquoProminently photocatalyticperformance of restacked titanate nanosheets associated withH2O2under visible light irradiationrdquo Powder Technology vol

275 pp 284ndash289 2015[23] M Nyman and D T Hobbs ldquoA family of peroxo-titanate

materials tailored for optimal strontium and actinide sorptionrdquoChemistry of Materials vol 18 no 26 pp 6425ndash6435 2006

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


in the significant improvement of the sorption ability forstrontium and actinides [14] Furthermore peroxotitanatesorbents prepared via modification with hydrogen peroxideare more superior to titanates prepared without hydrogenperoxide [15] Titanate materials that are synthesized inthe presence of H

2O2and undergo modified postsynthesis

of sodium titanate with H2O2demonstrate good radionu-

clide sorption selectivity kinetics and capacity [7 16] Amethodology to modify the synthesis of sodium titanate forproducing materials which achieve significantly improvedstrontium and actinide removal and increased capacity andsorption kinetics was proposed in an earlier study [17]However to the best of our knowledge studies on the effectof hydrogen peroxide content on as-prepared peroxotitanatematerials for the treatment of radioactive wastewater haveseldom been reported

In this study peroxo-modified sodium titanate was pre-pared by the hydrothermal method using hydrogen peroxideat different titaniumhydrogen peroxide molar ratios Effectsof different titaniumhydrogen peroxide molar ratios on theproperties of peroxotitanate materials were determined Thehigh adsorption efficiency of peroxotitanate for the treatmentof stimulant wastewater was confirmed

2 Experimental

21 Reagents Analytical-grade chemicals were used asreceived without any further purification Ti(O-iC

3H7)4

(98 purity Fluka) NaOH (ge96 purity Showa) HNO3

(65 purity Showa) NaNO2(985 purity Showa) H

2O2

(35 purity HSE) and lanthanide metal (Merck 99) wereused for ion-exchange experiments with compounds such asSr(NO

3)2 Co(NO

3)2sdot6H2O Nd(NO

3)3sdot6H2O Sm(NO

3)3sdot

6H2O Eu(NO

3)3sdot6H2O Ce(NO

3)3sdot6H2O Gd(NO

3)3sdot6H2O

Y(NO3)3sdot6H2O La(NO

3)3sdot6H2O and ultrapure water

(purity ge 98)

22 Preparation of Peroxotitanate Materials Figure 1 showsthe flowchart of the synthesis of peroxotitanate materialsFirst 06 g of NaNO

2was dissolved in 100mL of 01MHNO

3

and added to a vessel Second Ti(O-iC3H7)4was slowly

added to an acetic acid solution which was stirred usinga magnetic stirrer for 30min and heated to 130∘C in anautoclave for 3 h Third NaOH was slowly added to thevessel using a reflux condenser for achieving pH of 6-7 Afteruniform stirring a white precipitate was observed and thenan appropriate amount of H

2O2was added to the system

The titanate rapidly formed from the titanium precipitatePeroxotitanate materials were also synthesized at varioushydrogen peroxideTi(O-iC

3H7)4molar ratios (HT molar

ratios)The solution gradually became transparent and brightyellow further forming a yellow peroxotitanate precipitateAfter the reaction was complete the precipitates were cooledand washed several times with DI water until the pH reachedapproximately 7 Finally the resulting precipitate was freeze-dried (lt01 torr and minus45∘C) followed by grinding affordingperoxo-modified titanate material Table 1 summarizes theHT molar ratios utilized for the synthesis of peroxotitanateunder different experimental conditions

Table 1Molar ratios of hydrogen peroxide and titanium isopropox-ide utilized for the synthesis of peroxotitanate materials underdifferent experimental conditions

Sample Reaction temp (∘C) pH Drying Ti H2O2

H1 130 6-7 F 1 1H2 130 6-7 F 1 2H3 130 6-7 F 1 3H4 130 6-7 F 1 4

Yellow precipitate

Suction filtration

Nanofiber

Treatment with DI water

Freeze-drying

TIPT + acetic acid

pH = 6sim7Stirring

H2O2

NaNO2 + HNO3

NaOH

Stirring for 3 h at 1130∘C

Figure 1 Flowchart of the synthesis of peroxotitanate materials bythe hydrothermal method

23 Instrumentation The glassware used for the experi-ments was soaked in concentrated HNO

3for 12 h and then

thoroughly washed using tap water and double-distilledwater followed by drying overnight in a hot-air oven at50∘C The crystal structures of the samples obtained wereinvestigated by X-ray diffraction (XRD PANalytical XrsquoPertPRO XRD CuK

120572radiation) and micro-Raman spectroscopy

(Dimension-P2 Raman) A Micromeritics ASAP 2020 ana-lyzer was employed for BET analysis TEMmeasurement wasperformed using a CM-200 TEM system (Philips) operatingat 200 kV Before TEM analysis the samples were sonicatedin ethanol for 15min followed by the deposition of 2-3 dropsof the sample on a thin carbon film supported on a perforatedcopper grid the samples were then dried overnight at 60∘CFourier transform infrared (FTIR) spectra were recorded ona spectrometer (Perkin Elmer) UV-vis diffuse reflectancespectra were recorded between 300 and 800 nm on a Jasco V-600 UV-vis spectrophotometer which was employed tomea-sure the red shift in samples All absorbance measurementswere recorded on a UV-vis spectrophotometer (Hitachi U-2800) equipped with a quartz cell of 1 cm Thermogravime-trydifferential thermal analysis (TGADTA) was performed








119909H2minus119909

Ti3O7structure




119909H2minus119909

Ti6O13



2(anatase)

lowastlowast lowast

lowastlowast

lowast

As-prepared

AnataseRutile

900∘C

800∘C

700∘C

600∘C

500∘C

400∘C

10 15 20 25 30 35 40 45 50 555 602120579 (degree)

Inte

nsity

(arb

itrar

y un

its)

NaHTi3O7

NaHTi6O13

lowast

Δ

ΔΔ

Δ

loz



119909H2minus119909




2in high tem-


2powder in NaOH


2Ti (OC3H7)4+NaOCH

3+ 5H2O


3OH + 8C

3H7OH

(1)







(b)

(a)

Inte

nsity

(au

)(d)

(c)














(A)HT = 0 1237 056 183HT = 1 468 022 190HT = 2 218 011 206HT = 3 364 019 206HT = 4 381 020 210


2between the









Pore

vol

ume (

mm3gmiddotn

m)

20 40 60 80 100 1200Pore diameter (nm)

02 04 06 08 1000

02468

101214

0

5

10

15

20

25

Volu

me a

dsor

bed

(cm3g

STP

)


(a)


0

Pore

vol

ume (

mm3gmiddotn

m)

0

1

2

3

4

5

Volu

me a

dsor

bed

(cm3g

STP

)

00

05

10

15

20

25

40 60 80 100 12020Pore diameter (nm)


(b)


(a) (b)

(c) (d)



900∘C800

∘C700∘C600

∘C

500∘C400

∘C300∘C200

∘C


Na a

tom

ic p

erce

nt (

)

381364218

468

1237

64

71

58

54

50

55

60

65

70

75

BET

surfa

ce ar

ea (m

2g

)

20

40

60

80

100

120

140

73

HT = 0 HT = 1 HT = 3 HT = 4HT = 2




2




HT = 0 195 552 55 195 1 283HT = 1 187 556 67 190 1 297HT = 2 171 582 76 171 1 340HT = 3 181 568 73 178 1 314HT = 4 183 572 70 175 1 313



1minus1198622)times (119881119882)







0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2





0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)


20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C




nanorod Na2Ti6O13





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










119909H2minus119909

Ti3O7structure




119909H2minus119909

Ti6O13



2(anatase)

lowastlowast lowast

lowastlowast

lowast

As-prepared

AnataseRutile

900∘C

800∘C

700∘C

600∘C

500∘C

400∘C

10 15 20 25 30 35 40 45 50 555 602120579 (degree)

Inte

nsity

(arb

itrar

y un

its)

NaHTi3O7

NaHTi6O13

lowast

Δ

ΔΔ

Δ

loz



119909H2minus119909




2in high tem-


2powder in NaOH


2Ti (OC3H7)4+NaOCH

3+ 5H2O


3OH + 8C

3H7OH

(1)







(b)

(a)

Inte

nsity

(au

)(d)

(c)














(A)HT = 0 1237 056 183HT = 1 468 022 190HT = 2 218 011 206HT = 3 364 019 206HT = 4 381 020 210


2between the









Pore

vol

ume (

mm3gmiddotn

m)

20 40 60 80 100 1200Pore diameter (nm)

02 04 06 08 1000

02468

101214

0

5

10

15

20

25

Volu

me a

dsor

bed

(cm3g

STP

)


(a)


0

Pore

vol

ume (

mm3gmiddotn

m)

0

1

2

3

4

5

Volu

me a

dsor

bed

(cm3g

STP

)

00

05

10

15

20

25

40 60 80 100 12020Pore diameter (nm)


(b)


(a) (b)

(c) (d)



900∘C800

∘C700∘C600

∘C

500∘C400

∘C300∘C200

∘C


Na a

tom

ic p

erce

nt (

)

381364218

468

1237

64

71

58

54

50

55

60

65

70

75

BET

surfa

ce ar

ea (m

2g

)

20

40

60

80

100

120

140

73

HT = 0 HT = 1 HT = 3 HT = 4HT = 2




2




HT = 0 195 552 55 195 1 283HT = 1 187 556 67 190 1 297HT = 2 171 582 76 171 1 340HT = 3 181 568 73 178 1 314HT = 4 183 572 70 175 1 313



1minus1198622)times (119881119882)







0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2





0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)


20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C




nanorod Na2Ti6O13





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(b)

(a)

Inte

nsity

(au

)(d)

(c)














(A)HT = 0 1237 056 183HT = 1 468 022 190HT = 2 218 011 206HT = 3 364 019 206HT = 4 381 020 210


2between the









Pore

vol

ume (

mm3gmiddotn

m)

20 40 60 80 100 1200Pore diameter (nm)

02 04 06 08 1000

02468

101214

0

5

10

15

20

25

Volu

me a

dsor

bed

(cm3g

STP

)


(a)


0

Pore

vol

ume (

mm3gmiddotn

m)

0

1

2

3

4

5

Volu

me a

dsor

bed

(cm3g

STP

)

00

05

10

15

20

25

40 60 80 100 12020Pore diameter (nm)


(b)


(a) (b)

(c) (d)



900∘C800

∘C700∘C600

∘C

500∘C400

∘C300∘C200

∘C


Na a

tom

ic p

erce

nt (

)

381364218

468

1237

64

71

58

54

50

55

60

65

70

75

BET

surfa

ce ar

ea (m

2g

)

20

40

60

80

100

120

140

73

HT = 0 HT = 1 HT = 3 HT = 4HT = 2




2




HT = 0 195 552 55 195 1 283HT = 1 187 556 67 190 1 297HT = 2 171 582 76 171 1 340HT = 3 181 568 73 178 1 314HT = 4 183 572 70 175 1 313



1minus1198622)times (119881119882)







0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2





0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)


20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C




nanorod Na2Ti6O13





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





Pore

vol

ume (

mm3gmiddotn

m)

20 40 60 80 100 1200Pore diameter (nm)

02 04 06 08 1000

02468

101214

0

5

10

15

20

25

Volu

me a

dsor

bed

(cm3g

STP

)


(a)


0

Pore

vol

ume (

mm3gmiddotn

m)

0

1

2

3

4

5

Volu

me a

dsor

bed

(cm3g

STP

)

00

05

10

15

20

25

40 60 80 100 12020Pore diameter (nm)


(b)


(a) (b)

(c) (d)



900∘C800

∘C700∘C600

∘C

500∘C400

∘C300∘C200

∘C


Na a

tom

ic p

erce

nt (

)

381364218

468

1237

64

71

58

54

50

55

60

65

70

75

BET

surfa

ce ar

ea (m

2g

)

20

40

60

80

100

120

140

73

HT = 0 HT = 1 HT = 3 HT = 4HT = 2




2




HT = 0 195 552 55 195 1 283HT = 1 187 556 67 190 1 297HT = 2 171 582 76 171 1 340HT = 3 181 568 73 178 1 314HT = 4 183 572 70 175 1 313



1minus1198622)times (119881119882)







0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2





0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)


20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C




nanorod Na2Ti6O13





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




900∘C800

∘C700∘C600

∘C

500∘C400

∘C300∘C200

∘C


Na a

tom

ic p

erce

nt (

)

381364218

468

1237

64

71

58

54

50

55

60

65

70

75

BET

surfa

ce ar

ea (m

2g

)

20

40

60

80

100

120

140

73

HT = 0 HT = 1 HT = 3 HT = 4HT = 2




2




HT = 0 195 552 55 195 1 283HT = 1 187 556 67 190 1 297HT = 2 171 582 76 171 1 340HT = 3 181 568 73 178 1 314HT = 4 183 572 70 175 1 313



1minus1198622)times (119881119882)







0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2





0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)


20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C




nanorod Na2Ti6O13





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 10 20 30 40 50 60Time (min)

020406080

100120140160180200220

Ion-

exch

ange

capa

city

(mg

g)

HT = 0

HT = 1

HT = 3

HT = 4

HT = 2





0 10 20 30 40 50 60 70 800

5

10

15

20

25

30

35

CeCoEu

GdLaNd

SmSrY

Rem

oval

effici

ency

()

Time (min)


20

0

40

60

80

100

120

Ion-

exch

ange

capa

city

(mg

g)

1044974 10011007

871

987

501 493

900∘C800

∘C700∘C600

∘C500∘C400

∘C300∘C200

∘C




nanorod Na2Ti6O13





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





4 Conclusions




2 With the




Competing Interests


Acknowledgments


References


















2on morphology and


















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article effect of hydrogen peroxide content on the ...research article effect of hydrogen...

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