Journal of Chemistry
Volume 2014 (2014), Article ID 450790, 7 pages
http://dx.doi.org/10.1155/2014/450790

Research Article

Adsorption of Arsenite by Six Submerged Plants from Nansi Lake, China

Zhibin Zhang,1,2 Yulin Sun,¹ Cuizhen Sun,¹ Ning Wang,¹ and Yanhao Zhang¹

¹School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, Shandong 250101, China
²Center for Sustainable Development & Global Competitiveness, Stanford University, Stanford, CA 94305, USA

Received 24 April 2014; Revised 15 September 2014; Accepted 27 October 2014; Published 13 November 2014

Academic Editor: Davide Vione

Copyright © 2014 Zhibin Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Nansi Lake is the largest and the most important freshwater lake in north China for the South-North Water Transfer Project. Due to long-time and large-scale fish farming of history, the excess fish food and excretion usually release pentavalent arsenic, which is converted into trivalent arsenic (As (III)) in the lake sediment and released into lake water. Adsorption of arsenite using six submerged plants (Mimulicalyx rosulatus, Potamogeton maackianus, Hydrilla, Watermifoil, Pteris vittata, and Potamogeton crispus) as adsorbing materials was investigated. The experimental data obtained have been analyzed using Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models and the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics models. According to the results, the As (III) equilibrium data agreed well with the Freundlich isotherm model. The adsorption capacity of the plants was in the following order: Potamogeton crispus > Pteris vittata > Potamogeton maackianus > Mimulicalyx rosulatus > Hydrilla > Watermifoil. The sorption system with the six submerged plants was better described by pseudo-second-order than by first-order kinetics. Moreover, the adsorption with Potamogeton crispus could follow intraparticle diffusion (IPD) model. The initial adsorption and rate of IPD using Potamogeton crispus and Pteris vittata were higher than those using other plants studied.

1. Introduction

Arsenic (As) is a naturally occurring element in the earth. It is found in soils, surface, and ground waters, in the atmosphere and organisms (including the human body) [1–3]. Elevated arsenic levels have been found in freshwater ecosystems such as lakes and rivers around the world due to anthropogenic inputs such as combustion of fossil fuels, mining and smelting, and the application of pesticide and preservatives and additives to livestock feed. The occurrence of high levels of naturally occurring arsenic in groundwater has also weakened the success of supplying safe water and about 35–77 million people are at risk of being exposed in Bangladesh [4]. Via the food-chain, As can eventually bioaccumulate to higher level that could pose a serious threat to human health. The uptake of arsenic can lead to health problems such as lung, kidney, bladder, and skin cancer as well as neurological disorders [5–8]. Due to the high toxicity and carcinogenicity of arsenic, its maximum concentration in drinking water was limited to 10 μg/L by the World Health Organization (WHO) and the Ministry of Health of the People’s Republic of China [9]. Therefore, developing economical, efficient, and reliable As removal technologies for water treatment is pressing.

The conventional technologies, such as coagulation, precipitation, ion exchange, and adsorption, are available to remove As. Adsorption is by far the most widely used, and activated carbon is the most commonly used sorbent. However, its use is costly to be implemented, so there has been considerable interest in the use of other adsorbing materials, particularly biosorbents [10, 11]. Plant-based remediation technology, called phytoremediation, has been cited as a promising approach to arsenic removal in waters contaminated with toxic heavy metals [12, 13]. This approach takes advantage of the natural ability of plants to remove, transform, or accumulate elements and compounds from the water and to metabolize various molecules in their tissues and it is an emerging cost-effective and ecofriendly technology [12, 14, 15]. However, the incorporation of heavy metals produces phytotoxic effects on plants resulting in reduction of biomass, which was the consequence of the inhibition of chlorophyll synthesis [16]. Adsorption of dead aquatic plants as a simple adsorbent, which is used to bind heavy metals from solutions, has advantages of high efficiency, low cost, and no nutrient requirements. Also, it is possible to recover heavy metals [17–19]. Macrophytes biomass including Spirodela intermedia, Lemna minor, and Pistia stratiotes was reported in the literature and the mechanism of simultaneous metal removal (Cd²⁺, Ni²⁺, Cu²⁺, Zn²⁺, and Pb²⁺) by them was investigated [20]. Nansi Lake (34°27′-35°20′N, 116°34′-117°21′ E) is located in Shandong province, with an area of 1266 km² and a mean depth of 1.5 m. The lake is the largest and the most important freshwater lake in north China for the South-North Water Transfer Project [21]. Due to the large-scale fish farming for a long time in this area, considerable amounts of excess feeding and fish excretion were deposited and accumulated in sediment of Nansi Lake. The fish food of history, containing large amount of arsanilic acid or roxarsone, usually releases pentavalent arsenic (As (V)) through the excess feeding and fish excretion, which is easily converted into trivalent arsenic (As (III)) in the lake sediment and released into lake water [22]. As (III) and As (V) are most responsible for water contamination among the various forms of arsenic [23]. Inorganic As (III) is more toxic and more mobile than As (V) due to the higher binding affinity to the sulfhydryl (–SH) groups of protein [24].

Therefore, it is necessary to systematically determine the adsorption potential of the abundant submerged plants in the Nansi Lake because of the low cost as adsorbing material, especially for developing countries, that could provide support to emergency treatment of water pollution accidents. In this work, Pteris vittata, Mimulicalyx rosulatus, Potamogeton maackianus, Hydrilla, Watermifoil, and Potamogeton crispus were used in the removal of As (III). The adsorption isotherms and kinetics of the six submerged plants for As (III) at low concentration were investigated and compared.

2. Methods and Materials

2.1. Materials

Six submerged plants (Mimulicalyx rosulatus, Potamogeton maackianus, Hydrilla, Watermifoil, Pteris vittata, and Potamogeton crispus) were collected from Nansi Lake and thoroughly rinsed with tap water to remove debris and sediments. Then, the washed plants were trimmed to similar shape, size, and leave density.

All the chemicals used in the experiments were of analytical grade. The As (III) stock solution was prepared by dissolving sodium arsenite (NaAsO₂, AR) in deionized water. The As (III) solutions were prepared by dilution of the stock solution of 1000 mg/L with deionized water. pH was controlled to 7.0 by 1.0 mol/L HCl and 0.1 mol/L NaOH.

In order to evaluate the possibility of the release of As from above these submerged plants, a control experiment was also set up with deionized water. Only minute quantity (negligible ppb level) of arsenic was found.

2.2. Measurement of Adsorption

Isotherm studies were carried out by adding dead submerged plants of 1.0 g in a 100 mL of 0.025, 0.050, 0.100, 0.500, and 1.000 mg/L arsenite solution at pH 7.0. The solution was shaken at 120 rpm at 13°C for 24 h. After equilibrium was reached, the solutions were filtered through 0.22 μm polytetrafluoroethylene (PTFE) film and the filtrates were analyzed to determine the concentration of residual As (III) with atom fluorescence spectroscopy (AFS). The instrument involves using a beam of light from an excitation source of lamps. The light excites the electrons in molecules of certain compounds and causes them to emit light. Absorption spectroscopy is measured by recording the emission spectra resulting from a range of excitation wavelengths. The adsorption capacity of plants could be calculated using the following equation [29]:

where (mg/g) is As (III) uptake, and (mg/L) are the initial and equilibrium As (III) concentration, respectively, (L) is the volume of solution, and (g) is the dry weight of plant used. Triplicate experiments were performed.

Kinetic studies were carried out by adding dead submerged plants of 1.0 g into a 100 mL of 1.000 mg/L arsenite solution at pH 7.0. The solution was shaken at 120 rpm at 13°C for up to 24 h. At 15 min, 30 min, 60 min, 180 min, 300 min, 600 min, and 1440 min, a small aliquot of the solution was taken and filtered, and the concentration of residual As (III) was determined by AFS. The adsorbed As (III) amount at time (min), (mg/mg), was calculated by the following equation [29]:

where and (mg/L) are the concentrations of As (III) at initial time and time (min), respectively. (L) is the volume of solution and (g) is the weight of plants used.

2.3. Adsorption Isotherm

The relationship between the equilibrium adsorption capacity of the plants and the equilibrium concentration of As (III) at constant temperature can be expressed by isothermal models. In order to establish the best-fit isotherm equation for adsorption data interpretation and prediction, the experimental equilibrium data were fitted into three isotherm models, namely, the Freundlich, Langmuir, and Dubinin-Radushkevich equations.

The Freundlich adsorption isotherm model describes the adsorption equilibrium on heterogeneous surfaces. The Freundlich equation can be expressed as follows [30]:

where    (mg/kg) represents the amount of As (III) adsorbed at equilibrium by unit weight of plant, (mg/L) is the equilibrium concentration of As (III) in the bulk solution, and the Freundlich constant ((mg/kg)(L/mg)1/n) indicates the adsorption capacity of the plants. A high value of implies high adsorptive capacities of plants. is the heterogeneity factor. When , the adsorption is favorable; when   , the adsorption is irreversible; and when , the adsorption is unfavorable [31].

A line form of (3) can be obtained by taking logarithms:

The Langmuir adsorption isotherm describes monolayer adsorption onto homogeneous surfaces when assuming that all the adsorption sites possess equal affinity for the sorbate and that adsorption at one site does not affect adsorption at an adjacent one. The Langmuir equation can be written as follows [32]:

where (mg/kg) is the maximum As (III) uptake and (L/mg) is the Langmuir constant related to the affinity between the sorbent and sorbate. Equation (5) can be transformed into the following linear form:

The Dubinin-Radushkevich (D-R) isotherm model is applied more generally than Langmuir isotherm, because it does not assume a homogeneous surface or constant sorption potential [33]. Dubinin-Radushkevich (D-R) isotherm has commonly been applied in the following form [34]:

where (mol²/KJ²) is a constant related to the mean adsorption energy, and is the Polanyi potential, which can be calculated from the equation

where is the absolute temperature in and is the universal gas constant (8.314 KJ/mol).

The mean energy of sorption, , is useful for estimating the type of sorption reaction and it is as follows:

2.4. Adsorption Kinetics Models

The adsorption kinetics can predict the rate of adsorption of As (III) by plants and provides valuable data for understanding the adsorption mechanism. The pseudo-first-order, pseudo-second-order, and the Weber and Morris intraparticle diffusion kinetics models were used to evaluate the adsorption kinetics.

With boundary conditions of at and at , the linear form of pseudo-first-order kinetic equation is given as follows [35]:

where (mg/kg) is the amount of As (III) adsorbed at time (h), and (1/h) is the adsorption rate constant, which can be determined from the slope and intercept of the linear plot of versus (h).

With boundary conditions of at and at , the linear form of pseudo-second-order kinetic equation is represented as follows [36, 37]:

where (kg/(h·mg)) is the adsorption rate constant, which can be calculated from the linear plot of   against time (h).

The intraparticle diffusion (IPD) was explored by using the intraparticle diffusion model which defines that, in the adsorption process, uptake varies almost proportionally with , rather than with the contact time. The intraparticle diffusion model is expressed as follows [38]:

where   (mg/(kg·h1/2)) is the rate constant, obtained from the slope of the straight line from a plot of versus , while (mg/kg) is the intercept that gives an idea about the thickness of the boundary layer. The larger the intercept, the greater the boundary layer effect.

3. Results and Discussion

3.1. Adsorption Isotherm

Figures 1, 2, and 3 report the plots of log versus log , versus , and log versus corresponding to Freundlich, Langmuir, and Dubinin-Radushkevich isotherm equations, respectively. The constants and correlation coefficients for the different isotherm models are presented in Table 1: the equilibrium adsorption data was better fitted to Freundlich isotherm model than Langmuir adsorption model for the adsorption process of the six submerged plants. The Freundlich isotherm describes multilayer adsorption. Higher correlation coefficient () for the Freundlich isotherm was found, confirming that the adsorption is multilayer under the experimental conditions used. The values of and were determined from the slopes and intercepts of the straight lines in Figure 2 and are listed in Table 1. The values of were in the range of 0.58–0.88 for Potamogeton crispus, Pteris vittata, Mimulicalyx rosulatus, and Hydrilla, indicating that As (III) was favorably adsorbed by these plants. The values of were 1.15 and 1.23 for Potamogeton maackianus and Watermifoil, indicating that As (III) was unfavorably adsorbed by these plants in this study. The values show that the order of As (III) adsorption potential of the plants was Potamogeton crispus > Pteris vittata > Potamogeton maackianus > Mimulicalyx rosulatus > Hydrilla > Watermifoil.

Table 1: Isotherm parameters for Langmuir, Freundlich, and Dubinin-Radushkevich models for As (III) adsorption at 13°C.

Plants
Freundlich model
Langmuir model
Dubinin-Radushkevich model

(mg/kg) (L/mg)
mg/kg
L/mg
mol²/kJ²
mg/kg
kJ/mol

Mimulicalyx rosulatus
7.60
0.70
0.97
3.09
10.92
0.82
0.029
5.52
4.12
0.85

Potamogeton maackianus
10.41
0.58
0.99
6.93
8.95
0.98
0.024
8.18
4.53
0.95

Hydrilla
8.78
0.59
0.92
18.08
1.91
0.89
0.028
7.97
4.23
0.93

Watermifoil
4.12
1.15
0.98
−0.83
−2.35
0.92
0.058
3.38
2.95
0.93

Pteris vittata
24.99
0.88
0.95
6.64
−3.49
0.91
0.044
22.68
3.37
0.93

Potamogeton crispus
39.88
0.99
0.99
−3.65
−3.59
0.95
0.055
23.39
3.02
0.98

Figure 1: The linearized Langmuir adsorption isotherms of As (III) by the submerged plants.

Figure 2: The linearized Freundlich adsorption isotherms of As (III) by the submerged plants.

Figure 3: The linearized D-R adsorption isotherms of As (III) by the submerged plants.

The Dubinin-Radushkevich isotherm model was also applied to estimate the type of adsorption process. If the value of is in the range of 8–16 kJ/mol, the adsorption process follows by chemical ion-exchange.  kJ/mol indicates that the adsorption process is of physical nature. However, if the value is more than 16 kJ/mol, the biological sorption prevails [22]. From Table 1, the values were lower than 8 kJ/mol. This supports the fact that the physical adsorption of As (III) played a significant role for the As (III) adsorption by Mimulicalyx rosulatus, Potamogeton maackianus, Hydrilla, Watermifoil, Pteris vittata, and Potamogeton crispus.

3.2. Adsorption Kinetics

Figures 4, 5, and 6 show the plots of versus , versus , and versus corresponding to pseudo-first-order, pseudo-second-order, and intraparticle diffusion (IPD) model, respectively. The regression coefficient was calculated from these plots and used as the fitting criterion to determine the applicability of the three models.

Figure 4: The linearized pseudo-first-order kinetics model for the removal of As (III) (°C, initial As (III) concentration = 1.000 mg/L).

Figure 5: The linearized pseudo-second-order kinetics model for the removal of As (III) (°C, initial As (III) concentration = 1.000 mg/L).

Figure 6: The linearized intraparticle diffusion model for the removal of As (III) (°C, initial As (III) concentration = 1.000 mg/L).

As shown in Figure 4 and Table 2, the estimated values from the linear plot of the pseudo-first-order model were much lower than the experimental values. Therefore, the kinetic process was not pseudo-first-order. In contrast, the pseudo-second-order model obtained high values which were approximately equal to the experimental values. Moreover, it had values higher than 0.98 for different plants, reflecting the most likely adsorption mechanism. The results suggest that the interfacial resistance was not the rate limiting step, because the adsorption of As (III) fitted pseudo-second-order kinetics [33].

Table 2: Kinetic parameters for pseudo-first-order, pseudo-second-order, and intraparticle diffusion model models for As (III) adsorption at 13°C.

Plants

mg/kg
Pseudo-first-order model
Pseudo-second-order model
Intraparticle diffusion model

mg/kg
1/h
mg/kg
kg/(h·mg)
mg/(kg·h1/2)
mg/kg

Mimulicalyx rosulatus
8.54
4.00
0.42
0.89
8.80
0.20
0.10
0.17
3.83
0.53

Potamogeton maackianus
9.85
7.15
0.56
0.99
10.17
0.16
1.00
0.20
3.96
0.65

Hydrilla
9.68
6.34
0.57
0.98
9.96
0.18
1.00
0.19
4.10
0.64

Watermifoil
5.78
2.72
0.48
0.80
6.07
0.075
0.99
0.13
1.95
0.58

Pteris vittata
24.50
9.15
0.46
0.67
25.00
0.098
1.00
0.44
11.99
0.57

Potamogeton crispus
23.49
17.95
0.15
0.92
25.12
0.017
0.98
0.50
5.23
0.94

The correlation coefficient values obtained by IPD model were lower than 0.7 for all of the tested plants except for Potamogeton crispus (i.e., ). IPD model is suitable for the description of the adsorption kinetics of As (III) into Potamogeton crispus because the correlation coefficient was 0.94. None of the plots pass through the origin. This shows that the intraparticle diffusion is not the only rate-limiting step and the boundary layer affects the adsorption process [39]. Thus other processes make a contribution to the removal of As (III) with these submerged plants in this study. Figure 6 and Table 2 show that intercept ( value) with Potamogeton crispus and Pteris vittata is much higher than for the other plants, indicating that Potamogeton crispus and Pteris vittata have a large initial amount of adsorption. The higher slope with Potamogeton crispus and Pteris vittata means that the rate of IPD was higher compared to the other plants.

For lower concentration values of arsenic, other plants were found to be used in several publications. The values of different plants have great differences. Potamogeton crispus and Pteris vittata, which had the largest arsenic (III) adsorption capacity in this experiment, were compared with the adsorption capacities of other plants from the literature. The results are listed in Table 3. From the table, we can conclude that Potamogeton crispus and Pteris vittata have large adsorption capacity and are well suited to remove arsenic from Nansi Lake.

Table 3: Comparison of adsorption capacities of various plants for arsenic removal from aqueous solutions.

Plant species
Adsorption capacity
Reference

(mg/kg)

Ranunculus flammula
5.21
[25]

Salvinia natans L.
22.50
[26]

Sparganium natans
11.37
[25]

Spirodela polyrhiza L.
26.47
[27]

Cardamine flexuosa
8.78
[25]

Vaccinium oxycoccos
3.67
[25]

Scenedesmus quadricauda
25.20
[28]

Pteris vittata
24.50
This study

Potamogeton crispus
23.49
This study

4. Conclusions

Results showed that adsorption isotherm favored Freundlich models and the adoption process could be fitted by the pseudo-second-order kinetics. The intraparticle diffusion was not the only rate-limiting step in the adsorption process.

Potamogeton crispus and Pteris vittata have large adsorption capacity and quick adsorption rate to equilibrium. The arsenic can be lowered to 0.05 mg/L in the case of initial concentration 0.1 mg/L [40]. The sorption of As by Potamogeton crispus and Pteris vittata can be a low cost and efficient basis for removal of low concentration As. The research findings merit further research to evaluate the practicality of their use in the field.

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

Acknowledgments

This work was financially supported by Shandong Province Financial Department and Environmental Protection Bureau (no. SDZS-2012-SHBT01), Shandong Natural Science Foundation (no. ZR2012EEQ024), and Doctor Foundation of Shandong Jianzhu University (no. XNBS1228). The advice and kind suggestions from the anonymous reviewers are highly acknowledged.

References

B. K. Mandal and K. T. Suzuki, “Arsenic round the world: a review,” Talanta, vol. 58, no. 1, pp. 201–235, 2002.

B. Dhir, S. A. Nasim, P. Sharmila, and P. Pardha Saradhi, “Heavy metal removal potential of dried Salvinia biomass,” International Journal of Phytoremediation, vol. 12, no. 2, pp. 133–141, 2010.

Z. Xie, Y. Luo, Y. Wang, X. Xie, and C. Su, “Arsenic resistance and bioaccumulation of an indigenous bacterium isolated from aquifer sediments of Datong Basin, Northern China,” Geomicrobiology Journal, vol. 30, no. 6, pp. 549–556, 2013.

M. Brömssen, L. Markussen, P. Bhattacharya et al., “Hydrogeological investigation for assessment of the sustainability of low-arsenic aquifers as a safe drinking water source in regions with high-arsenic groundwater in Matlab, southeastern Bangladesh,” Journal of Hydrology, vol. 518, part C, pp. 373–392, 2014.

H. H. dos Santos, C. A. Demarchi, C. A. Rodrigues, J. M. Greneche, N. Nedelko, and A. Ślawska-Waniewska, “Adsorption of As(III) on chitosan-Fe-crosslinked complex (Ch-Fe),” Chemosphere, vol. 82, no. 2, pp. 278–283, 2011.

V. C. Silva, S. M. Almeida, C. Resgalla, J.-F. Masfaraud, S. Cotelle, and C. M. Radetski, “Arsenate (As V) in water: quantitative sensitivity relationships among biomarker, ecotoxicity and genotoxicity endpoints,” Ecotoxicology and Environmental Safety, vol. 92, pp. 174–179, 2013.

S. Bhattacharya, K. Gupta, S. Debnath, U. C. Ghosh, D. Chattopadhyay, and A. Mukhopadhyay, “Arsenic bioaccumulation in rice and edible plants and subsequent transmission through food chain in Bengal basin: a review of the perspectives for environmental health,” Toxicological and Environmental Chemistry, vol. 94, no. 3, pp. 429–441, 2012.

S. Kar, J. P. Maity, J.-S. Jean, et al., “Health risks for human intake of aquacultural fish: arsenic bioaccumulation and contamination,” Journal of Environmental Science and Health Part A: Toxic/Hazardous Substances and Environmental Engineering, vol. 46, no. 11, pp. 1266–1273, 2011.

Y. Wang, S. D. Lu, X. Li, and Y. J. Wu, “Research advances and prospects in arsenic removal from water,” Environmental Science & Technology, vol. 33, no. 9, pp. 102–107, 2010.

J. Ng, W. H. Cheung, and G. McKay, “Equilibrium studies for the sorption of lead from effluents using chitosan,” Chemosphere, vol. 52, no. 6, pp. 1021–1030, 2003.

D. Mohan and C. U. Pittman Jr., “Arsenic removal from water/wastewater using adsorbents—a critical review,” Journal of Hazardous Materials, vol. 142, no. 1-2, pp. 1–53, 2007.

M. A. Rahman, H. Hasegawa, K. Ueda, T. Maki, and M. M. Rahman, “Influence of EDTA and chemical species on arsenic accumulation in Spirodela polyrhiza L. (duckweed),” Ecotoxicology and Environmental Safety, vol. 70, no. 2, pp. 311–318, 2008.

N.-X. Wang, Y. Li, X.-H. Deng, A.-J. Miao, R. Ji, and L.-Y. Yang, “Toxicity and bioaccumulation kinetics of arsenate in two freshwater green algae under different phosphate regimes,” Water Research, vol. 47, no. 7, pp. 2497–2506, 2013.

S. Sauge-Merle, C. Lecomte-Pradines, P. Carrier, S. Cuiné, and M. DuBow, “Heavy metal accumulation by recombinant mammalian metallothionein within Escherichia coli protects against elevated metal exposure,” Chemosphere, vol. 88, no. 8, pp. 918–924, 2012.

R. Larios, R. Fernández-Martínez, I. LeHecho, and I. Rucandio, “A methodological approach to evaluate arsenic speciation and bioaccumulation in different plant species from two highly polluted mining areas,” Science of the Total Environment, vol. 414, pp. 600–607, 2012.

M. Delgado, M. Bigeriego, and E. Guarniola, “Uptake of Zn, Cr and Cd by water hyacinths,” Water Research, vol. 27, no. 2, pp. 269–272, 1993.

F. Veglio and F. Beolchini, “Removal of metals by biosorption: a review,” Hydrometallurgy, vol. 44, no. 3, pp. 301–316, 1997.

I. A. H. Schneider and J. Rubio, “Sorption of heavy metal ions by the nonliving biomass of freshwater macrophytes,” Environmental Science and Technology, vol. 33, no. 13, pp. 2213–2217, 1999.

I. A. H. Schneider, J. Rubio, and R. W. Smith, “Biosorption of metals onto plant biomass: exchange adsorption or surface precipitation?” International Journal of Mineral Processing, vol. 62, no. 1–4, pp. 111–120, 2001.

P. Miretzky, A. Saralegui, and A. Fernández Cirelli, “Simultaneous heavy metal removal mechanism by dead macrophytes,” Chemosphere, vol. 62, no. 2, pp. 247–254, 2006.

S. L. Wang, C. Y. Lin, X. Z. Cao, and X. Zhong, “Arsenic content, fractionation, and ecological risk in the surface sediments of lake,” International Journal of Environmental Science and Technology, vol. 9, no. 1, pp. 31–40, 2012.

K. Angkanaporn and K. D. C. Kiratisehwe, “Effects of the dietary inclusion of fish meal, rock phosphate and roxarsone on arsenic residues in tissues of broilers,” Thai Journal of Veterinary Medicine, vol. 38, no. 4, pp. 57–64, 2008.

S. K. Maji, Y.-H. Kao, C.-J. Wang, G.-S. Lu, J.-J. Wu, and C.-W. Liu, “Fixed bed adsorption of As(III) on iron-oxide-coated natural rock (IOCNR) and application to real arsenic-bearing groundwater,” Chemical Engineering Journal, vol. 203, pp. 285–293, 2012.

P. E. Burns, S. Hyun, L. S. Lee, and I. Murarka, “Characterizing As(III, V) adsorption by soils surrounding ash disposal facilities,” Chemosphere, vol. 63, no. 11, pp. 1879–1891, 2006.

C. Bergqvist and M. Greger, “Arsenic accumulation and speciation in plants from different habitats,” Applied Geochemistry, vol. 27, no. 3, pp. 615–622, 2012.

M. A. Rahman, H. Hasegawa, K. Ueda, T. Maki, and M. M. Rahman, “Influence of phosphate and iron ions in selective uptake of arsenic species by water fern (Salvinia natans L.),” Chemical Engineering Journal, vol. 145, no. 2, pp. 179–184, 2008.

M. A. Rahman, H. Hasegawa, K. Ueda, T. Maki, C. Okumura, and M. M. Rahman, “Arsenic accumulation in duckweed (Spirodela polyrhiza L.): a good option for phytoremediation,” Chemosphere, vol. 69, no. 3, pp. 493–499, 2007.

J. Y. Zhang, T. D. Ding, and C. L. Zhang, “Biosorption and toxicity responses to arsenite (As[III]) in Scenedesmus quadricauda,” Chemosphere, vol. 92, no. 9, pp. 1077–1084, 2013.

Y. Tang, L. Chen, X. Wei, Q. Yao, and T. Li, “Removal of lead ions from aqueous solution by the dried aquatic plant, Lemna perpusilla Torr,” Journal of Hazardous Materials, vol. 244-245, pp. 603–612, 2013.

O. Moradi, A. Fakhri, S. Adami, and S. Adami, “Isotherm, thermodynamic, kinetics, and adsorption mechanism studies of Ethidium bromide by single-walled carbon nanotube and carboxylate group functionalized single-walled carbon nanotube,” Journal of Colloid and Interface Science, vol. 395, no. 1, pp. 224–229, 2013.

D. Feller, M. Vasiliu, D. J. Grant, and D. A. Dixon, “Thermodynamic properties of arsenic compounds and the heat of formation of the as atom from high level electronic structure calculations,” The Journal of Physical Chemistry A, vol. 115, no. 51, pp. 14667–14676, 2011.

Z. A. ALOthman, M. Naushad, and R. Ali, “Kinetic, equilibrium isotherm and thermodynamic studies of Cr(VI) adsorption onto low-cost adsorbent developed from peanut shell activated with phosphoric acid,” Environmental Science and Pollution Research, vol. 20, no. 5, pp. 3351–3365, 2013.

X.-J. Xiong, X.-J. Meng, and T.-L. Zheng, “Biosorption of C.I. Direct Blue 199 from aqueous solution by nonviable Aspergillus niger,” Journal of Hazardous Materials, vol. 175, no. 1–3, pp. 241–246, 2010.

M. Jain, V. K. Garg, and K. Kadirvelu, “Adsorption of hexavalent chromium from aqueous medium onto carbonaceous adsorbents prepared from waste biomass,” Journal of Environmental Management, vol. 91, no. 4, pp. 949–957, 2010.

J. X. Zhang and L. L. Ou, “Kinetic, isotherm and thermodynamic studies of the adsorption of crystal violet by activated carbon from peanut shells,” Water Science and Technology, vol. 67, no. 4, pp. 737–744, 2013.

F. Yu, Y. Wu, J. Ma, and C. Zhang, “Adsorption of lead on multi-walled carbon nanotubes with different outer diameters and oxygen contents: kinetics, isotherms and thermodynamics,” Journal of Environmental Sciences, vol. 25, no. 1, pp. 195–203, 2013.

Y. S. Ho and G. McKay, “Sorption of dye from aqueous solution by peat,” Chemical Engineering Journal, vol. 70, no. 2, pp. 115–124, 1998.

B. Das, R. R. Devi, I. M. Umlong, K. Borah, S. Banerjee, and A. K. Talukdar, “Arsenic (III) adsorption on iron acetate coated activated alumina: thermodynamic, kinetics and equilibrium approach,” Journal of Environmental Health Science & Engineering, vol. 11, no. 1, pp. 42–47, 2013.

W. Zhang, Z. Xu, B. Pan, L. Lv, Q. Zhang, and W. Du, “Assessment on the removal of dimethyl phthalate from aqueous phase using a hydrophilic hyper-cross-linked polymer resin NDA-702,” Journal of Colloid and Interface Science, vol. 311, no. 2, pp. 382–390, 2007.

S. Yu, Research on Arsenic Removal by Biological Technology from Natural Water, Shandong Jianzhu University, 2012.