Preparation of a novel chelating fiber with amino and its adsorption for Hg2+

Reporter ： Yang Ying

Tutor: Professor Chen Shuixia

v The effective treatment of heavy metals ions in the environment has been one of the major issues owing to economic and environmental factors.

v Adsorption is one of the methods commonly used to remove heavy metal ions from various aqueous solutions with relatively low metal ion concentrations.

v Chelating fibers are effective adsorbents and have several advantages : easy to prepare, highly selective, high absorption capacity, and good removal for heavy metals ions

Ⅰ.Significance of this study

v Graft polymerization of glycidyl methacrylate (GMA) onto PP

� increase surface-to-surface interactions

� the epoxy group of GMA have a unique reaction capability

� ring opening with various compounds possessing hydroxyl, amine, or activated methylene groups

� introduce amine groups which are well-established chelating groups.

Ⅰ. Significance of this study

II. Objective

v To prepare a novel chelating fiber with amino group.

v Properties of the fiber:

1) high thermal stability and mechanical properties

2) high adsorption capacity for Hg2+

3) thorough removal of trace Hg2+

Ⅲ. Research programmes

γ-ray

GMA DETAn

mC O

OHC CH2

ONH

HNH2N

n

mC O

OHC CH2

OH

n

PP-g-GMAACHF

Scheme l. Synthesis of chelating fiber with amino groups (ACHF )

Ⅳ. results and discussion

v 1 Preparation of ACHF v 2 IR spectra v 3 SEM photographsv 4 Mechanical propertiesv 5 Thermal stability v 6 Adsorption capacity

Effects of reaction conditions on grafting rate of PP-g-GMA

v 1.1The reaction medium v 1.2The reaction temperaturev 1.3The reaction time v 1.4The concentration of monomer

1 Preparation of ACHF

10 20 30 40 50

0

20

40

60

80

100

Acetone

Methanol

THF

Gra

ftin

g r

ate

/%

Concentration of Monomer /%

Fig.1Effect of reaction medium on grafting rate

1.1The reaction medium

Fig.2 Effect of reaction temperature on grafting rate

50 60 70 80 90 100 110

0

20

40

60

80

100

120

Gra

ftin

g r

ate

/%

Reaction temperature/0C

1.2The reaction temperature

1 2 3 4 5

0

20

40

60

80

100

120

Gra

ftin

g r

ate

/%

Time/h

Fig.3 Effect of reaction time on grafting rate

1.3The reaction time

10 20 30 40 50 600

50

100

150

200

250

Gra

ftin

g r

ate

/%

the concentration of Monomer /%

Fig.4 Effect of the concentration of monomer on grafting rate

1.4The concentration of monomer

The optimal grafting conditions:

v solvent tetrahydrofuranv reaction time 3hv reaction temperature 100oCv monomer concentration 50 wt%

2 IR spectra

Fig.5 FT-IR spectra of original PP, PP-g-GMA and ACHF

1000 1500 2000 2500 3000 3500

ACHF

PP-g-GMA

PP

Wavenumber/cm-1

1000 1500 2000 2500 3000 3500

ACHF

ACHF-Hg2+

Wavenumber/cm-1

Fig.6 FT-IR spectra of ACHF and ACHF chelated Hg2+

2 IR spectra

3 SEM photographs

Fig.6 SEM photographs of original PP and ACHF

4 Mechanical properties

Tab.1 Mechanical properties of PP and ACHF fibers

Fiber Elongation/mm Tensile strength/cN

PP 2.3 11.5

ACHF 2.8 16.9

Growth/% 47 22

5 Thermal stability

100 200 300 400 500 600

0

20

40

60

80

100

ACHF PP-g-GMA PP

Mas

s/%

Temperature/0C

Fig.7 TGA results of PP, PP-g-GMA and ACHF

6 Adsorption capacity

v 6.1Effect of pH on adsorption for Hg2+

v 6.2Effect of initial concentration on adsorption v 6.3Effect of coexistence ion Cu2+ on adsorptionv 6.4Dynamic adsorption

1 2 3 4 5 6 7

20

40

60

80

100

120

140

C=100mg.L-1;time=24h;T=29.90C

Ads

orpt

ion

capa

city

/mg.

g-1

pH value

Fig.8 Effect of pH on the adsorption capacity of Hg2+

6.1 Effect of pH

0 200 400 600 800 10000

100

200

300

400

500

600

700

800

900

pH=4;time=20h,T=29.90C

Ads

orpt

ion

capa

city

/mg.

g-1

C0/mg.L-1

Fig.9 Adsorption capacity of ACHF for high concentration of Hg2+ in water

6.2Effect of initial concentration

0 200 400 600 800 10000

2

4

6

8

10

12

14

16

0.0

0.2

0.4

0.6

0.8

1.0

Max allowable conc.

of Hg2+ for drinking water

C

e/u

g.L

-1

C0/ug.L-1

ad

sorp

tion

ca

pa

city

/mg

.g-1

Fig.10 Removal of trace Hg2+ in water

6.2Effect of initial concentration

Conc. of Cu2+/mg.L-1 0 100 200 400 600 800 1000

initial conc. of Hg2+/ mg.L-1 100 100 100 100 100 100 100

residual conc. of Hg2+ / mg.L-1 0 0 0 0 0 0 0.08

Tab.2 Hg2+ adsorption amount on ACHF with Cu2+ coexist in solution

6.3Effect of coexistence ion Cu2+

Fig.11 Effect of adsorption time on the adsorption capacity of Hg2+

6.4Dynamic adsorption

0 100 200 300 400 500 600

0

20

40

60

80

100

C0=123mg.L-1

A

dsor

ptio

n ca

paci

ty/m

g.g-1

Adsorption time/min

Fig.12 Effect of adsorption time on the adsorption capacity of Hg2+

6.4Dynamic adsorption

0 100 200 300 400 500 600

0.0

0.2

0.4

0.6

0.8

C0=500ug.L-1

A

dsor

ptio

n ca

paci

ty/m

g.g-1

Adsorption time/min

Ⅴ. Conclusions

v A chelating fiber with amino (ACHF) has been prepared by pre-irradiation grafting and consequently aminating.

v The results show that ACHF has better elasticity and flexibility, and good stability for common use.

v Its adsorption capacity for Hg2+ is up to 785.28mg/g .

v The fiber can get rid of trace mercury in water to meet the max allowable concentration of Hg2+ for drinking water.

Acknowlegements:

v Professor Chen is acknowledged for both the support of this work and his sincere instruction.

v Dr. Ma, Dr. Zhang and other colleagues

v Financial supports from Key project of Sci-Tech of Guangdong Province, and Innovation Research Fund of the School of Chemistry and Chemical Engineering