Accepted Manuscript

Title: A novel biodegradable �-cyclodextrin-based hydrogelfor the removal of heavy metal ions

Author: Zhanhua Huang Qinling Wu Shouxin Liu Bin Zhang

PII: S0144-8617(13)00400-1DOI: http://dx.doi.org/doi:10.1016/j.carbpol.2013.04.047Reference: CARP 7663

To appear in:

Received date: 22-2-2013Revised date: 8-4-2013Accepted date: 12-4-2013

Please cite this article as: Huang, Z., Wu, Q., Liu, S., & Zhang, B., A novel biodegradable�-cyclodextrin-based hydrogel for the removal of heavy metal ions, CarbohydratePolymers (2013), http://dx.doi.org/10.1016/j.carbpol.2013.04.047

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Highlights

►Novel β-cyclodextrin-based gel (CAM) with three-dimensional network

structure was obtained. ► CAM hydrogel is biodegraded by Gloeophyllum

trabeum. ► The biodegradation efficiency of CAM reached 79.4 % in

Gloeophyllum trabeum. ► CAM exhibited an excellent performance for

Pb2+

and Cu2+

.

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A novel biodegradable β-cyclodextrin-based hydrogel 1

for the removal of heavy metal ions 2

Zhanhua Huanga,b

*, Qinling Wub, Shouxin Liu

a, Bin Zhang

a 3

4

a Key Laboratory of Bio-based Material Science and Technology of 5

Ministry of Education, Northeast Forestry University, Harbin 150040, 6

China 7

b School of Renewable Natural Resources, Louisiana State University 8

Agricultural Center, Baton Rouge, LA 70803, USA 9

10

*Corresponding author: Zhanhua Huang 11

Key Laboratory of Bio-based Material Science and Technology of 12

Ministry of Education, Northeast Forestry University, Harbin 150040, 13

China 14

15

Tel: 86-451-82192905; Fax: 86-451-2905; 16

E-mail: huangzh1975@163.com 17

18

19

20

21

22

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Abstract: A novel biodegradable β-cyclodextrin-based gel (CAM) was 23

prepared and applied to the removal of Cd2+

, Pb2+

and Cu2+

ions from 24

aqueous solutions. CAM hydrogel has a typical three-dimensional 25

network structure, and showed excellent capability for the removal of 26

heavy metal ions. The effect of different experimental parameters, such as 27

initial pH, adsorbent dosage and initial metal ion concentration, were 28

investigated. The adsorption isotherm data fitted well to the Freundlich 29

model. The adsorption capacity was in the order Pb2+

>Cu2+

>Cd2+

under 30

the same experimental conditions. The maximum adsorption capacities 31

for the metal ions in terms of mg/g of dry gel were 210.6 for Pb2+

, 116.41 32

for Cu2+

, and 98.88 for Cd2+

. The biodegradation efficiency of the resin 33

reached 79.4% for Gloeophyllum trabeum. The high adsorption capacity 34

and kinetics results indicate that CAM can be used as an alternative 35

adsorbent to remove heavy metals from aqueous solution. 36

37

38

39

Keywords: β-Cyclodextrin; Adsorbent; Biodegradable; Adsorption; 40

Heavy metal removal 41

42

43

44

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1. Introduction 45

In recent years, with the development of industrialization, heavy 46

metal ion pollution of water is a serious matter. In the environment, heavy 47

metal ions cannot be degraded naturally and accumulate in living 48

organisms through food chain circulation. Furthermore, excessive heavy 49

metal ion accumulation becomes toxic and directly affects the growth and 50

physiological functions of organisms, leading to disease and even death 51

of organisms (Meral Yurtsever, & Ayhan Sengil, 2009). 52

The typical methods for heavy metal ions removal from industrial 53

wastewater include chemical precipitation, reverse osmosis, membrane 54

systems, solvent extraction, adsorption, electrolytic processes, ion 55

exchange processes, and biological methods. Among these methods, 56

adsorption is one of the most economically favorable and it is technically 57

an easy method (Vismara, et al., 2009). However, many absorbents, as 58

well as being economically expensive, have disadvantages such as low 59

adsorption capacity and non-biodegradability. Thus, considerable 60

attention has been focused on the removal of heavy metal ions from 61

wastewater using biodegradable adsorbents derived from low-cost 62

materials. 63

β-Cyclodextrin (β-CD) has many hydroxyl groups on the outside of 64

the cyclic cavity. These hydroxyl groups can enhance the adsorption of 65

heavy metal ions by strong interactions between the hydroxyl groups and 66

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metal ions (Chao, et al., 2008). Another β-CD is the cyclic 67

oligosaccharide formed from seven glucose molecules by 68

α-1-4-glucosidase linkages. β-CD and its derivatives are biodegradable 69

(Del Valle, 2004). 70

In this paper, a novel biodegradable β-CD based adsorbent (CAM, 71

Fig. 1) was prepared by cross-linking reactions under microwave 72

irradiation. The objective of the study was to search for a biodegradable 73

adsorbent with a high adsorption capacity for heavy metal ions. The 74

chemical structure of CAM was characterized, and the adsorption 75

behavior of CAM for Cd2+

, Pb2+

and Cu2+

was investigated. The possible 76

adsorption mechanisms were also explored by fitting to the isotherm 77

equations. 78

79

Fig. 1. Main structure of CAM resin. 80

81

2. Experimental 82

2.1. Materials 83

β-CD, acrylic acid (AA), N,N’-methylene-bis-acrylamide (MBA), 84

and Ce(NH4)2(NO3)6 were purchased from the chemical reagent 85

development center of Kemiou Engineering (Tianjin, China). Aspergillus 86

niger (A. niger), Penicillium and Gloeophyllum trabeum were obtained 87

from the Laboratory of Forest Protection of the Northeast Forestry 88

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University. The standard stock solutions (500mg/L) of Cd2+

, Pb2+

and 89

Cu2+

were prepared from their nitrate salts. The pH of the experimental 90

solutions was adjusted using 0.1 M HCl and 0.1 M NaOH. All reagents 91

used were of analytical grade, and all solutions were prepared with 92

distilled water. 93

2.2. Microwave preparation of CAM 94

β-CD, AA, and MBA were mixed in a 250 mL three-neck reaction 95

bottle with a mass ratio of 1:6:3. The resulting mixture was dissolved in 96

0.01 M NaOH solution with stirring to adjust the mixture to a specified 97

degree of neutralization. The mixture was uniformly mixed to dissolve 98

the solid samples. Then, the three-neck reaction bottle was installed on 99

the microwave synthesizer. Nitrogen flowed through for the whole 100

reaction process. 0.01 g Ce(NH4)2(NO3)6 (quantitative initiator) was then 101

added in the three-neck reaction bottle using a funnel at a constant rate of 102

1 d/s to 2 d/s with stirring at 60 °C. After then, the microwave irradiated 103

reaction was maintained 15 min exposure time and at 250 W microwave 104

power. Then, the mixture was passed through a filter, and the filtered cake 105

was extracted for 6-8h by acetone under 50℃, filter again, the filtered 106

cake was washed by alcohol for three times in order to remove unreacted 107

monomer. Finally, the filtered cake was dried at 40 C for 48 h to give 108

CAM. 109

2.3. Characterization 110

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The Fourier transform-infrared (FTIR) spectra were recorded on a 111

MAGNA 560 FTIR spectrometer (Thermo Nicolet Corporation, USA) 112

using KBr discs in the range 400 cm–1 to 4000 cm

–1. Scanning electron 113

microscope (SEM) images and energy dispersive X-ray analyses (EDX) 114

were obtained using a FEI QUANTA 200 Microscope (FEI Corporation, 115

Netherlands). Solid-state carbon-13 cross-polarization and 116

magnetic-angle spinning nuclear magnetic resonance (13

C CPMAS NMR) 117

spectra were obtained using a Bruker Avance 400 NMR spectrometer 118

(BRUKER Corporation, Germany) with a frequency of 75.47 MHz and a 119

sample spin of 4.0 kHz. 120

2.4. Adsorption experiments 121

Cd2+

, Pb2+

and Cu2+

aqueous solutions were prepared from the 122

corresponding standard stock solutions by diluting with deionized water 123

to give different concentrations (25 mg/L, 50 mg/L, 100 mg/L and 150 124

mg/L). 0.1 g of the CAM was mixed with 200 mL of each salt solution, 125

and the water absorbency was then measured. Buffer solutions with pH 126

values of 2, 4, 6, 8, 10, and 12 were prepared using 0.1 g of the CAM 127

mixed with 200 mL of the buffer solutions of different pH values. After 128

saturation, the solutions were filtered and weighed, the hydrogel 129

characteristics were determined, and the absorbency was calculated. The 130

adsorption capacity (Q) and removal rate (A) were calculated as follows: 131

Q= (1) 132

%10000

00

VC

VCVC ee

m

VCVC ee00

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A= (2) 133

where C0 and Ce are the initial and equilibrium concentrations of the 134

metal ions, V0 and Ve are the initial and equilibrium volumes of the 135

solution, and m is the dose of CAM. 136

2.5. Determination of biodegradability 137

CAM sheets with size 1 cm × 2 cm were obtained from the CAM 138

products by cutting, and were then weighed and labeled separately. The 139

sheets were placed in 18 PDA plates containing fungi (six plates each of 140

A. niger, Penicillium and Gloeophyllum trabeum), sealed with tape, and 141

incubated at 30 °C. Then, the CAM gels were filtered, dried, weighed, 142

and the biodegradation was observed every 72 h. 143

144

3. Results and discussion 145

3.1. SEM–EDX analysis 146

0.1 g of CAM was added into saturated solutions of Cd2+

, Pb2+

and 147

Cu2+

. After static adsorption for 6 h, filtering and purifying, three 148

different test samples were obtained. The Cu, Pb and Cd distributions in 149

the samples were studied by SEM–EDX analysis (Jacobson, et al., 2007). 150

Fig. 2a-c shows the mapping of Cu, Pb and Cd and the corresponding 151

scanning image in the samples. The EDX spectra at single regions of the 152

sample (Fig. 2) indicated the relative proportion of the different atoms. 153

As shown in Fig. 2, Cu, Pb and Cd are present in the test samples with 154

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proportions of 50.55 wt%, 81.52 wt% and 47.52 wt%, respectively. The 155

results indicated that the Pb content was significantly higher than Cu and 156

Cd in the respective solutions. 157

The SEM images of the resin CAM hydrogel in Cd2+

, Pb2+

and Cu2+

158

saturated solutions are shown in Fig. 2a-c. After adsorption, the internal 159

structure of the CAM hydrogel had an obvious three-dimensional 160

network, and the network size increased with increasing adsorption 161

content of the metal to the CAM adsorbent surface. However, in this 162

study, the SEM–EDX technique was not sensitive enough to identify the 163

differences of metal speciation generated during adsorption. 164

165

Fig. 2. SEM–EDX spectra of the adsorbent in the Cd2+

, Pb2+

and Cu2+

166

solutions. 167

168

3.2. FTIR spectra 169

Fig. 3 shows the FTIR spectra of β-CD and CAM. The characteristic 170

absorption peaks of β-CD (3406, 2928, 1156 and 1028 cm-1

), PAA (2830, 171

1721 and 1450 cm-1

) and MBA (1560 and 1450 cm-1

) are observed in the 172

spectra. In the FTIR spectra, the peak for the stretching vibration 173

absorption of -NH2 is 1560 cm-1

(Tripathy, et al., 2009), while the peak at 174

1450 cm-1

corresponds to the C-N stretching vibration of the MBA unit. 175

Moreover, the lack of a characteristic -C=C absorption peak indicates that 176

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a polymerization reaction occurred. Based on these results, it can be 177

concluded that -C=O and -NH2 were introduced to the CAM. 178

179

Fig. 3. FTIR spectra of β-CD and CAM. 180

181

Fig. 4 shows the 13

C NMR spectra of β-CD and CAM. Fig. 3 indicates 182

that there is a dissymmetrical β-CD cavity, because of an obvious signal 183

split of characteristic carbon atoms, with the split peaks at 101–104 ppm 184

being the C1 signal peaks connected to the β-CD vertical glycosidic 185

linkage. The chemical shifts at 80–85 ppm are the characteristic signals 186

for C4; the five split peaks at 58–63 ppm are characteristic of the signal 187

for C6; and the chemical shifts at 72–78 ppm are the cyclic carbons C2, 188

C3, C5, which are not connected to the glycosidic bond but have the same 189

characteristics of the separate peaks (Huang, et al., 2012). 190

It can be seen from the 13

C NMR spectra of CAM that the 191

spectrogram was smooth and split peaks were not observed. The 192

characteristic peak at 185.24 ppm represents the carbon signal from C=O. 193

The peaks at 20–50 ppm are characteristic signal peaks for different alkyl 194

group in the polymer chains. The peaks at 104.44 ppm and 82.11 ppm 195

represent C1 and C4 signals of the glucose residues, and the split peaks at 196

65.06 ppm and 61.41 ppm represent C6 signals of the glucose residues. 197

The peak at 73.55 ppm was identified as the cyclic carbons C2, C3 and 198

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C5, which are not connected to the glycosidic linkage. In certain 199

environments, the resonance peaks of C2, C3, and C5 tend to overlap to 200

form a single peak (Lu, et al., 2008). The peaks at 20–50 ppm are 201

characteristic signal peaks of alkyl groups in polymer chains. The above 202

results indicate that the cycle cavity of β-CD was open during 203

polymerization. 204

205

Fig. 4. Solid-state 13

CNMR spectra of β-CD and CAM. 206

207

3.3. Effect of different experimental parameters on metal ion adsorption 208

to CAM 209

The effects of adsorbent dosage, initial pH and initial metal ion 210

concentration on the uptake and removal rate of CAM are shown in Fig. 5. 211

As shown in Fig. 5a, the removal rate of Cd2+

, Pb2+

and Cu2+

shows a 212

trend of initially increasing and then decreasing when the CAM dose was 213

increased from 0.01 to 0.2 g/L. In contrast, the uptake of Cd2+

, Pb2+

and 214

Cu2+

gradually decreases from 228.91 to 49.03 mg/g, 505.60 to 63.29 215

mg/g, and 188.25 to 49.86 mg/g, respectively. A possible reason could be 216

that the increase in adsorbent provides excess active groups beyond the 217

capacity to be accepted by the metal ions. Moreover, the competition for 218

adsorption sites on the adsorbent between water and the metal ions leads 219

to an increase in water uptake and a decrease in the removal rate of the 220

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metal ions (Naiya, et al., 2009). As shown in Fig. 5b, the adsorption 221

capacities increased significantly with an increase in solution pH from 2 222

to 5. At lower solution pH values, H+

competes with metal ions for the 223

adsorption sites, resulting in the surface of the adsorbent occupied by 224

more H+ and reducing the complexation of the metal ions on the surface 225

of the adsorbent (Liang, et al., 2010). At higher solution pH values, the 226

surface of the adsorbent is occupied by more negative charges, which 227

attracts more metal ions. The effect of initial metal ion concentration on 228

the uptake is shown in Fig. 5c. The results indicate that the adsorption 229

capacities increase with increasing initial concentration of metal ions, and 230

the removal rate initially increases and then decreases. When the initial 231

concentration of metal ions increases, the increase in metal ions 232

combining with the active groups on the adsorbent gradually decreases, 233

which results in a gradual increase in the adsorption capacity. In addition, 234

more metal ions are left in solution because of saturation of the 235

adsorption sites (Cao, et al., 2010). Thus, when the concentration of metal 236

ions increase, the increase in metal ions combining with the active groups 237

gradually decreases. 238

239

Fig. 5. Effect of the (a) adsorbent dosage, (b) initial pH, and (c) initial 240

metal ion concentration on the adsorption capacities of Cd2+

, Pb2+

241

and Cu2+

.

242

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243

3.4. Adsorption isotherm 244

The adsorption isotherms were evaluated using the Langmuir and 245

Freundlich isotherm models. The Langmuir isotherm model (Sharma, & 246

Mishra, 2010) is given by 247

qe = KLCe/(1+ aLCe), (3) 248

where qe (mg/g) and Ce (mg/L) are the amount of metal ion adsorbed per 249

unit weight of adsorbent and the unadsorbed metal ion concentration in 250

solution at equilibrium, respectively. The empirical constants KL and aL 251

of the Langmuir model are related to the maximum adsorptive capacity of 252

the adsorbent (L/g) and the bonding strength (L/mg), respectively. 253

The Freundlich isotherm model (Dabrowski, 2001) is given by 254

logqe = logKF+1/nlogCe, (4) 255

where qe is the amount adsorbed at equilibrium (mg/g), Ce is the 256

equilibrium concentration of metal ions (mg/L), and KF (mg/g) and n (g/L) 257

are Freundlich constants related to the adsorption capacity and the 258

intensity of adsorption, respectively. 259

The values of the isotherm constants and the correlation coefficients 260

for the isotherm plots of Cd2+

, Pb2+

and Cu2+

are given in Table 1. The 261

highest numerical value of KF (115.46) was obtained for Pb2+

, followed 262

by Cu2+

(18.97) and then Cd2+

(11.62). The results indicate that the 263

equilibrium adsorption data for CAM fits the Freundlich isotherm model 264

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better than the Langmuir model. Therefore, the adsorption mechanism of 265

metal ions to CAM takes place through an ion exchange process 266

(Homagai, et al., 2010). 267

268

Table 1. Adsorption isotherm constants of the Langmuir and Freundlich 269

models for Cd2+

, Pb2+

and Cu2+

ions adsorbed to CAM. 270

271

3.5. Adsorption kinetics 272

The adsorption capacities of CAM gel for Cd2+

, Pb2+

and Cu2+

273

solutions are shown in Fig. 6. The adsorption capacities of the metal ions 274

occurred in the order Pb2+

(210.6 mg/g) > Cu2+

(116.41 mg/g) > Cd2+

275

(98.88 mg/g). The results indicate that CAM has excellent adsorption 276

performance for heavy metal ions, and the adsorption rate is fast, 277

reaching equilibrium within 60-90 min. A high correlation between the 278

experimental data and the quasi-second order adsorption rate equation 279

was obtained. The results of R2 for each metal ion are 0.971 (Cd

2+), 0.987 280

(Pb2+

), and 0.983 (Cu2+

). 281

282

Fig. 6. Effect of adsorption time on the adsorption capacities of CAM 283

for Cd2+

, Pb2+

and Cu2+

. 284

285

3.6. Biodegradation of CAM 286

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The degradation efficiency of CAM resin gel in A. niger, Penicillium 287

and Gloeophyllum trabeum is shown in Fig. 7. The degradation was 288

observed to be very slow with Penicillium, with only 6.31% of the CAM 289

gel degraded after 3 days and the degradation efficiency reaching a 290

maximum of 18.11% after 21 days. In A. niger, the CAM gel degradation 291

efficiency rapidly increased with time. After 3 days, the degradation 292

efficiency was 11.2%, but after 18 days it reached 68.19%. With 293

Gloeophyllum trabeum, the degradation efficiency was 39.26% after 3 294

days, and 79.4% after 21 days. The CAM block samples turned into fluid 295

in 3 days. These results indicate that the CAM gel is biodegradable by 296

Gloeophyllum trabeum. The order of the fungi based on the resin 297

degradation efficiency is as follows: Gloeophyllum trabeum > A. niger > 298

Penicillium. 299

300

Fig. 7. Fungus degradation of CAM 301

302

4. Conclusions 303

A biodegradable β-cyclodextrin-based hydrogel (CAM) was prepared 304

and shown to be an excellent adsorbent for the removal of Pb2+

, Cu2+

and 305

Cd2+

ions from aqueous solution. The adsorption capacities of CAM were 306

in the order: Pb2+

(210.6 mg/g) > Cu2+

(116.41 mg/g) > Cd2+

(98.88 mg/g). 307

After adsorption, the internal structure of CAM hydrogel had an obvious 308

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three-dimensional network structure. The adsorption mechanism of the 309

metal ions with CAM was through an ion exchange process. CAM 310

hydrogel is biodegradable by Gloeophyllum trabeum, and the degradation 311

efficiency was 79.4% after 21 days. This study shows that CAM is an 312

eco-friendly adsorption material that is effective in removing heavy metal 313

heavy metal ions from aqueous solution. 314

Acknowledgments 315

This work was supported by the Central University Basic Scientific 316

Research Project of China (Grant no. DL11EB01) and the National 317

Natural Science Foundation of China (Grant no. 31000277). We also 318

thank the Ph.D. program of the Foundation of the Ministry of Education 319

of China (Grant no. 20100062120005). 320

321

322

323

324

325

326

327

328

329

330

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334

335

336

References 337

Cao, J., Tan, Y.B., Che, Y.J., & Xin, H.P. (2010). Novel complex gel beads composed 338

of hydrolyzed polyacrylamide and chitosan: An effective adsorbent for the 339

removal of heavy metal from aqueous solution. Bioresource Technology, 101, 340

2558-2561. 341

Chao, Y., Jin, Z.Y., Xu, X.M, Zhuang, H.N, & Shen, W.Y. (2008). Preparation and 342

stability of the inclusion complex of astaxanthin with 343

hydroxypropyl-β-cyclodextrin. Food Chemistry, 109, 264-268. 344

Del Valle E.M. (2004). Cyclodextrins and their uses: a review. Process Biochemistry, 345

39, 1033-1046. 346

Dabrowski, A. (2001). Adorption-from theory to practice. Advances in Colloid and 347

Interface Science, 93, 135-224. 348

Homagai, P.L., Ghimire, K.N., & Inoue, K. (2010). Adsorption behavior of heavy 349

metals onto chemically modified sugarcane bagasse. Bioresource Technology, 101, 350

2067-2069. 351

Huang, Z.H., Liu, S.X., Zhang, B., Xu, L.L., & Hu, X.F. (2012). Equilibrium and 352

kinetics studies on the adsorption of Cu(II) from the aqueous phase using a 353

β-cyclodextrin-based adsorbent. Carbohydrate. Polymers. 88, 609-617. 354

Jacobson, A.R., Dousset, S., Andreux, F., & Baveye, P.C. (2007). Electron Microprob- 355

e and Synchrotron X-ray Fluorescence Mapping of the Heterogeneous 356

Distribution of Copper in High-Copper Vineyard Soils. Environmental Science & 357

Technology, 41, 6343-6349. 358

Liang, S., Guo, X.Y., Feng, N.C., & Tian, Q.C. (2010). Isotherms, kinetics and 359

thermodynamic studies of adsorption of Cu2+

from aqueous solutions by Mg2+

/K+ 360

type orange peel adsorbents. Journal of Hazardous Materials, 174, 756-762. 361

Lu, D.D., Yang, L.Q., Zhou, T.H., & Lei, Z.Q. (2008). Synthesis, characterization and 362

properties of biodegradable polylactic acid-β-cyclodextrin cross-linked copolymer 363

microgels. European Polymer Journal, 44, 2140-2145. 364

Naiya, T.K., Bhattacharya, A.K., & Das, S.K. (2009). Adsorption of Cd(II) and Pb(II) 365

from aqueous solutions on activated alumina. Journal of Colloid and Interface 366

Science.333, 14-26. 367

Page 18 of 25

Accep

ted

Man

uscr

ipt

17

Ngah, W.S.W., & Hanafiah, M.A.K. (2008). Adsorption of copper on rubber (Hevea 368

brasiliensis) leaf powder: Kinetic, equilibrium and thermodynamic studies. 369

Biochemical Engineering Journal, 39, 521-530. 370

Sharma, A.K., & Mishra, A.K. (2010). Microwave induced β-cyclodextrin 371

modification of chitosan for lead sorption. International Journal of Biological 372

Macromolecules, 47, 410-419. 373

Tripathy, J., Mishra D. K., & Behari, K. (2009). Graft copolymerization of 374

N-vinylformamide onto sodium carboxymethylcellulose and study of its swelling, 375

metal ion sorption and flocculation behavior. Carbohydrate Polymers, 75, 376

604-611. 377

Vismara, E., Melone, L., Gastaldi, G., Cosentino, C., & Torri, G. (2009). Surface 378

functionalization of cotton cellulose with glycidyl methacrylate and its application 379

for the adsorption of aromatic pollutants from wastewaters. Journal of Hazardous 380

materials, 170, 798-808. 381

Yurtsever, M., & Ayhan Sengil, i. (2009). Biosorption of Pb(II) ions by modified 382

quebracho tannin resin. Journal of Hazardous materials, 163, 58-64. 383

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List of Table

Table 1 Adsorption isotherm constants of Langmuir and Freundlich

models for Cd2+

, Pb2+

and Cu2+

ions adsorbed by CAM

Table(s)

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Table 1

Model Coefficient Cd2 Cu2+ Pb2+

Langmuir qmax(mg/g) 98.88 116.41 210.60

KL(L/g) 17.53 30.74 42.04

R2 0.896 0.909 0.922

Freundlich KF (mg/g) 11.62 18.97 115.46

n 0.174 0.305 0.181

R2 0.967 0.995 0.989

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Figure Captions

Fig.1. Main structure of CAM resin

Fig.2. SEM-EDX spectrum of the adsorbent in Cd2+

, Pb2+

and Cu2+

solution

Fig.3. FTIR spectra of β-CD and CAM

Fig.4. Solid-state 13

CNMR spectra of β-CD and CAM

Fig.5. Effect of the adsorbent dosage (a), initial pH (b) and initial metal

concentration (c) on the adsorption capacities of Cd2+

, Pb2+

and

Cu2+

Fig.6. Effect of adsorption time on the adsorption capacities of Cd2+

, Pb2+

and Cu2+

Fig.7. Mycete degradation results of CAM

Figure(s)

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Fig.1

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Fig.2

Fig.3

a b c

3406

2928

1156

1450 1721

1028

2830

1560

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Fig.4

Fig.5

a

b

20 40 60 80 100 120 140 1600

40

80

120

160

200

240

20 40 60 80 100 120 140 160

20

40

60

80

100

re

moval effic

iency(%

)

Initial concentration(mg/L)

Cd2+

Pb2+

Cu2+

20 40 60 80 100 120 140 160

20

40

60

80

100

120

rem

oval effic

iency(%

)

Initial concentration(mg/L)

Cd2+

Pb2+

Cu2+

Cu2+

Cd2+

Pb2+

Up

take

(mg

/g)

Initial concentration(mg/L)

c

0.00 0.05 0.10 0.15 0.20

0

50

100

150

200

250

300

350

400

450

500

550

0.00 0.05 0.10 0.15 0.2010

20

30

40

50

60

70

80

90

Cu2+

Pb2+

Cd2+

Up

take

(mg

/g)

Adsorbent doseage(g/L)

Adsorbent doseage(g/L)

rem

oval effic

iency(%

)

Cd2+

Pb2+

Cu2+

2.0 2.5 3.0 3.5 4.0 4.5 5.00

20

40

60

80

100

120

140

2.0 2.5 3.0 3.5 4.0 4.5 5.00

10

20

30

40

50

60

70

pH

Upta

ke(m

g/g

)

Cd2+

Pb2+

Cu2+

rem

oval effic

iency(%

)

pH

Cd2+

Pb2+

Cu2+

CAM

250 200 150 100 50 0 -50

65.0

6

46.3

5

61.4

1

27.7

1

39.8

7

82.1

173

.55

104.

44

185.

24

110 100 90 80 70 60 50

104.

30

102.

57103.

53

101.

84

73.9

6

80.9

6

78.8

176

.46

75.2

8 72.4

3

60.0

260.6

158

.99

62.3

663

.98

73.0

8

82.6

081

.74

84.3

8

β-CD

Page 25 of 25

Accep

ted

Man

uscr

ipt

5

Fig.6

Fig.7

2 4 6 8 10 12 14 16 18 20 22

10

20

30

40

50

60

70

80

degradation time/d

deg

rad

atio

n r

ate

/%

Gloeophyllum trabeum

Aspergillus niger

Penicillium

0 20 40 60 80 100 120 140 160 180 200 220 2400

40

80

120

160

200

240

Upta

ke(m

g/g

)

T(min)

25mg/L Pb2+

50mg/L Pb2+

100mg/LPb2+

150mg/LPb2+

0 20 40 60 80 100 120 140 160 180 200 220 2400

20

40

60

80

100

120

140

Up

take

(mg

/g)

T(min)

25mg/L Cu2+

50mg/L Cu2+

100mg/LCu2+

150mg/LCu2+

0 20 40 60 80 100 120 140 160 180 200 220 2400

20

40

60

80

100

120

140

Up

take

(mg

/g)

T(min)

25mg/L Cd2+

50mg/L Cd2+

100mg/L Cd2+

150mg/L Cd2+