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1.
To develop an efficient bio-immobilization approach for the remediation of heavy metal pollution in soil, a mutant species of Bacillus subtilis (B38) was obtained by ultraviolet irradiation and selection under high concentration of cadmium (Cd) in a previous study. In the present study, to check the applicability of this mutated species to the sorption and immobilization of other metals, the sorption of four heavy metals, Cd, chromium (Cr), mercury (Hg), and lead (Pb), on living and nonliving B38 in single- and multiple-component systems under different conditions was investigated using batch experiments. Rapid metal binding occurred on both living and nonliving B38 during the beginning of the biosorption. The sorption kinetics followed the exponential equation for living biomass and the pseudo-first-order Lagergren model for nonliving biomass, with r 2 values in the range of 0.9004-0.9933. The maximum adsorptive quantity of the heavy metals on B38 changed with the solution pH, temperature, biomass dose, and ionic strength. The nonliving biomass generally showed greater or similar adsorptive capacities as compared with the living biomass and was not likely to be affected by the solution parameters. The bacterium had a stronger affinity to the cationic heavy metals than to the anionic one, and the equilibrium sorption amounts were 210.6, 332.3, and 420.9 mg/g for Cd(II), Hg(II), and Pb(II), respectively. The results of binary and ternary sorption experiments indicated that the metals with the higher sorption capacity in the single-component systems showed greater inhibitory effects on the biosorption of other metal ions in the multiple-component systems, but the sorption sites of Hg and Cd or Pb are likely to be different. The results of this study illustrated that the mutant species is a promising biosorbent for the remediation of multiple heavy metals.  相似文献   

2.
The sorption capacity of nanoporous titanosilicate Engelhard titanosilicate number 4 (ETS-4) and silica-coated magnetite particles derivatised with dithiocarbamate groups towards Hg(II) was evaluated and compared in spiked ultra-pure and spiked surface-river water, for different batch factors. In the former, and using a batch factor of 100 m3/kg and an initial Hg(II) concentrations matching the maximum allowed concentration in an effluent discharge, both materials achieve Hg(II) uptake efficiencies in excess of 99 % and a residual metal concentration lower than the guideline value for drinking water quality. For the surface-river water and the same initial concentration, the Hg(II) uptake efficiency of magnetite particles is outstanding, achieving the quality criteria established by the Water Framework Directive (concerning Hg concentration in surface waters) using a batch factor of 50 m3/kg, while the efficiency of ETS-4 is significantly inferior. The dissimilar sorbents’ Hg(II) removal efficiency is attributed to different uptake mechanisms. This study also highlights the importance of assessing the effective capacity of the sorbents under realistic conditions in order to achieve trustable results.  相似文献   

3.
Kwon JS  Yun ST  Kim SO  Mayer B  Hutcheon I 《Chemosphere》2005,60(10):1416-1426
We conducted kinetic and equilibrium sorption experiments on removal of Zn(II) from aqueous solutions by scoria (a vesicular pyroclastic rock with basaltic composition) from Jeju Island, Korea, in order to examine its potential use as an efficient sorbent. The batch-type kinetic sorption tests under variable conditions indicated that the percentage of Zn(II) removal by scoria increases with decreasing initial Zn(II) concentration, particle size, and sorbate/sorbent ratio. However, the sorption capacity decreases with the decrease of the initial Zn(II) concentration and sorbate/sorbent ratio. Equilibrium sorption tests show that Jeju scoria has a larger capacity and affinity for Zn(II) sorption than commercial powdered activated carbon (PAC); at initial Zn(II) concentrations of more than 10mM, the sorption capacity of Jeju scoria is about 1.5 times higher than that of PAC. The acquired sorption data are better fitted to the Langmuir isotherm than the Freundlich isotherm. Careful examination of ionic concentrations in sorption batches suggests that the sorption behavior is mainly controlled by cation exchange and typically displays characteristics of 'cation sorption'. The Zn(II) removal capacity decreases when solution pH decreases because of the competition with hydrogen ions for sorption sites, while the Zn(II) removal capacity increases under higher pH conditions, likely due to hydroxide precipitation. At an initial Zn(II) concentration of 5.0mM, the removal increases from 70% to 96% with the increase of initial pH from 3.0 to 7.0. We recommend Jeju scoria as an economic and efficient sorbent for Zn(II) in contaminated water.  相似文献   

4.
Mercury (Hg) is a toxic element that is emitted to the atmosphere through human activities, mainly fossil fuel combustion. Hg accumulations in soil are associated with atmospheric deposition, while coal-burning power plants remain the most important source of anthropogenic mercury emissions. In this study, we analyzed the Hg concentration in the topsoil of the Kozani–Ptolemais basin where four coal-fired power plants (4,065 MW) run to provide 50 % of electricity in Greece. The study aimed to investigate the extent of soil contamination by Hg using geostatistical techniques to evaluate the presumed Hg enrichment around the four power plants. Hg variability in agricultural soils was evaluated using 276 soil samples from 92 locations covering an area of 1,000 km2. We were surprised to find a low Hg content in soil (range 1–59 μg kg?1) and 50 % of samples with a concentration lower than 6 μg kg?1. The influence of mercury emissions from the four coal-fired power plants on soil was poor or virtually nil. We associate this effect with low Hg contents in the coal (1.5–24.5 μg kg?1) used in the combustion of these power plants (one of the most Hg-poor in the world). Despite anthropic activity in the area, we conclude that Hg content in the agricultural soils of the Kozani–Ptolemais basin is present in low concentrations.  相似文献   

5.
Effective disposal of pumpkin husk (PH) as a redundant waste is a significant work for environmental protection and full utilization of resource. Predictive modeling of sorption of Lanaset Red (LR) G on PH was investigated in a batch system as functions of particle size, adsorbent dose, pH, temperature, and initial dye concentration. Fourier transform infrared spectroscopy attenuated total reflectance spectra of PH powders before and after the sorption of LR G were determined. Sorption process was found to be dependent on particle size, adsorbent dose, pH, temperature, initial dye concentration, and contact time. Amine and amide groups of PH had significant effect on the sorption process. The pHzpc of PH was found as 6.4. Sorption process was very fast initially and reached equilibrium within 60 min. Dynamic behavior of sorption was well represented by logistic and Avrami models. The sorption of LR G on PH was excellently described by Langmuir model, indicating a homogeneous phenomenon. Monolayer sorption capacity decreased from 440.78 to 436.28 mg g?1 with increasing temperature. Activation energy, thermodynamic, and desorption studies showed that this process was physical character, exothermic, and spontaneous. This study confirmed that PH as an effective and low-cost adsorbent had a great potential for the removal of LR G as an alternative eco-friendly process.  相似文献   

6.
Jeong J  Jurng J 《Chemosphere》2007,68(10):2007-2010
The removal of elemental mercury (Hg(0)) with the reactive species produced from dielectric barrier discharge (DBD) was studied. The effects of the operating parameters, such as the applied voltage, residence time, initial concentration and co-existence of other pollutants, were investigated. The removal of Hg(0) was significantly promoted by an increase in the applied voltage of the DBD reactor system. The presence of NO gas decreased the Hg(0) removal efficiency within the range of input powers tested compared to the case of Hg(0)-only due to the competition for ozone between Hg(0) and NO gas in the DBD reactor.  相似文献   

7.
The purpose of this study is to examine on removal of arsenic from water by biosorption through potential application of herbal dye wastes. Four different flower dye residues (after extraction of natural dye) viz. Hibiscus rosasinensis, Rosa rosa, Tagetes erecta, and Canna indica were utilized successfully for the removal of arsenic from aqueous solution. Batch studies were carried out for various parameters viz. pH, sorbent dose, contact time, initial metal ion concentration, and temperature. Data were utilized for isothermal, kinetic, and thermodynamic studies. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDAX), and Fourier transform infrared (FTIR) analyses of biomass were performed. The results showed that 1 g/100 ml for 5.0–5.5 h contact time at pH 6.0–7.5 with agitation rate 150 rpm provided 98, 96, 92, and 85 % maximum absorption of arsenic by R. rosa, H. rosasinensis, T. erecta, and C. indica, respectively, at initial concentration of 500 ppb. Data followed Langmuir isotherm showing sorption to be monolayer on heterogeneous surface of biosorbent. Negative values of ΔG° indicated spontaneous nature, whereas ΔH° indicates exothermic nature of system followed by pseudo-first-order adsorption kinetics. FTIR results showed apparent changes in functional group regions after metal chelation. SEM and EDAX analyses showed the changes in surface morphology of all test biosorbents. Herbal dye wastes, used as biosorbent, exhibited significant (85–98 %) removal of arsenic from aqueous solution. Hence, these biosorbents are cost-effective, easily available, eco-friendly, and comparatively more effective than other biosorbents already in use. These may be used to remove arsenic and other toxic metals from water.  相似文献   

8.
The use of effective disposal of redundant pumpkin husk (PH) to remove pollutants is an important issue for environmental protection and utilization of resource. The aim of this study was to remove a potentially toxic reactive azo dye, Reactive Red (RR) 120, by widespread PH as a low-cost adsorbent. Particle size, adsorbent dose, pH, temperature, initial dye concentration, and contact time affected the sorption process. Amine, amide, hydroxyl, and carboxyl groups of PH played significant roles on the sorption process. Rapid sorption occurred within the first 2 min and equilibrium was reached within 60 min. Sorption kinetic was well represented by logistic equation. Generated secondary logistic model can be used to describe effects of initial dye concentration, contact time, and temperature by a single equation with high R 2 value. Monolayer sorption capacity was found as 98.61 mg g-1. Activation energy, thermodynamic, and desorption studies showed that this process was physical, endothermic, and spontaneous. This study indicated that redundant PH as a low-cost adsorbent had a great potential for the removal of RR 120 as an alternative eco-friendly process.  相似文献   

9.
To evaluate the biosorption efficacy of submerged aquatic plant Hydrilla verticilata for arsenic uptake from drinking water. H. verticillata, a submerged aquatic plant was utilized successfully for arsenic uptake from aqueous solution. Batch studies with various parameters viz. pH, sorbent dose, contact time, initial metal ion concentration, and temperature were carried out. Data were utilized to plot Lagergren graph along with pseudo-second-order graphs for kinetic studies to estimate the removal efficacy and to determine the nature of reaction. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) have been performed for characterization of metals on biomass. The study showed 96.35 % maximum absorption of arsenic by H. verticilata at initial concentration of 100 ppb with 0.5 g of biomass/100 ml for 5 h contact time at pH?6.0 with 150 rpm agitation rate. Data followed Langmuir isotherm showing sorption to be monolayer on homogeneous surface of biosorbent. The negative values of ΔG° indicated spontaneous nature; whereas ΔH° indicates exothermic nature of system and negative value of ?S° entropy change correspond to a decrease in the degree of freedom to the adsorbed species followed by pseudo-second-order adsorption kinetics. FTIR and SEM results showed apparent changes in functional group regions after metal chelation and the changes in surface morphology of biosorbent. This is a comparatively more effective, economic, easily available, and environmentally safe source for arsenic uptake from solution due to its high biosorption efficacy than other biosorbents already used.  相似文献   

10.
Total mercury concentrations were determined in the gonadal tissues of 15 female and 10 male European perch (Perca fluviatilis) from one location of the stream “Jevanský potok” located about 30 km from Prague (Czech Republic). Tissue samples were frozen at ?26 °C in polypropylene containers until further processing, which was carried out using an Advance Mercury Analyser (single purpose atomic absorption spectrometer). Mercury concentrations were present in all analysed gonad samples, and ranged from 2.3 to 12.7 μg/kg wet weight. However, we determined a mean Hg concentration (9.45 μg/kg) in male gonads that was 2.4 times greater than that of female gonads (3.9 μg/kg). This is an important finding when taking into account fish sex in environmental pollution monitoring (especially for mercury contamination).  相似文献   

11.
Arsenic contamination of groundwater is a major threat to human beings globally. Among various methods available for arsenic removal, adsorption is fast, inexpensive, selective, accurate, reproducible and eco-friendly in nature. The present paper describes removal of arsenate from water on zirconium oxide-coated sand (novel adsorbent). In the present work, zirconium oxide-coated sand was prepared and characterised by infrared and X-ray diffraction techniques. Batch experiments were performed to optimise different adsorption parameters such as initial arsenate concentration (100–1,000 μg/L), dose (1–8 g/L), pH of the solution (2–14), contact time (15–150 min.), and temperature (20, 30, 35 and 40 °C). The experimental data were analysed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Furthermore, thermodynamic and kinetic parameters were evaluated to know the mode of adsorption between ZrOCMS and As(V). The maximum removal of arsenic, 97 %, was achieved at initial arsenic concentration of 200 μg/L, after 75 min at dosage of 5.0 g/L, pH?7.0 and 27?±?2 °C. For 600 μg/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 μg/g at 35 °C. Kinetic modelling data indicated that adsorption process followed pseudo-second-order kinetics. The mechanism is controlled by liquid film diffusion model. Thermodynamic parameter, ΔH°, was ?57.782, while the values of ΔG° were ?9.460, ?12.183, ?13.343 and ?13.905 kJ/mol at 20, 30, 35 and 40 °C, respectively, suggesting exothermic and spontaneous nature of the process. The change in entropy, ΔS°?=??0.23 kJ/mol indicated that the entropy decreased due to adsorption of arsenate ion onto the solid adsorbent. The results indicated that the reported zirconium oxide-coated marine sand (ZrOCMS) was good adsorbent with 97 % removal capacity at 200 μg/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10 μg/L, and in real situation, this low concentration can be achieved through this adsorbent. Besides, the adsorption capacity showed that this adsorbent may be used for the removal of arsenic from any natural water resource.  相似文献   

12.
The main purpose of this study was to investigate the effectiveness of Lactobacillus 12 and Lactobacillus rhamnosus as both cells and biomasses for the removal of dye from real textile dyeing wastewater. The removal experiments were conducted according to the Box–Behnken experimental design, and the regression equations for the removal of dye were determined by the Minitab 14 program. The optimum variables were found to be 10 g/?L biomass concentration for biomasses, 3 for initial pH of the solution, and 20 °C for temperature with an observed dye removal efficiency of about 60 and 80 % with L. 12 and L. rhamnosus biomasses, respectively. Scanning electron microscopy and Fourier transform infrared spectroscopy images also showed that the biomass characteristics studied were favored by the sorption of the dye from the textile industry wastewater. Consequently, these biomasses may be considered as good biosorbents due to their effective yields and the lower cost of the removal of dyes from the effluents of the textile dyeing house.  相似文献   

13.

Introduction

The removal of heavy metals by natural adsorbent has become one of the most attractive solutions for environmental remediation. Natural clay collected from the Late Cretaceous Aleg formation, Tunisia was used as a natural adsorbent for the removal of Hg(II) in aqueous system.

Methods

Physicochemical characterization of the adsorbent was carried out with the aid of various techniques, including chemical analysis, X-ray diffraction, Fourier transform infrared and scanning electron micrograph. Batch sorption technique was selected as an appropriate technique in the current study. Method parameters, including pH, temperature, initial metal concentration and contact time, were varied in order to quantitatively evaluate their effects on Hg(II) adsorption onto the original and pillared clay samples. Adsorption kinetic was studied by fitting the experimental results to the pseudo-first-order and pseudo-second-order kinetic models. The adsorption data were also simulated with Langmuir, Freundlich and Temkin isotherms.

Results

Results showed that the natural clay samples are mainly composed of silica, alumina, iron, calcium and magnesium oxides. The sorbents are mainly mesoporous materials with specific surface area of <250 m2 g?1. From the adsorption of Hg(II) studies, experimental data demonstrated a high degree of fitness to the pseudo-second-order kinetics with an equilibration time of 240 min. The equilibrium data showed the best model fit to Langmuir model with the maximum adsorption capacities of 9.70 and 49.75 mg g?1 for the original and aluminium pillared clays, respectively. The maximum adsorption of Hg(II) on the aluminium pillared clay was observed to occur at pH 3.2. The calculated thermodynamic parameters (?G°, ?H° and ?S°) showed an exothermic adsorption process. The entropy values varied between 60.77 and 117.59 J?mol?1 K?1, and those of enthalpy ranged from 16.31 to 30.77 kJ mol?1. The equilibrium parameter (R L) indicated that the adsorption of Hg(II) on Tunisian smectitic clays was favourable under the experimental conditions of this study.

Conclusion

The clay of the Aleg formation, Tunisia was found to be an efficient adsorbent for Hg(II) removal in aqueous systems.  相似文献   

14.
Bench-scale testing of elemental mercury (Hg0) sorption on selected activated carbon sorbents was conducted to develop a better understanding of the interaction among the sorbent, flue gas constituents, and Hg0. The results of the fixed-bed testing under simulated lignite combustion flue gas composition for activated carbons showed some initial breakthrough followed by increased mercury (Hg) capture for up to approximately 4.8 hr. After breakthrough, the Hg in the effluent stream was primarily in an oxidized form (>90%). Aliquots of selected activated carbons were exposed to simulated flue gas containing Hg0 vapor for varying time intervals to explore surface chemistry changes as the initial breakthrough, Hg capture, and oxidation occurred. The samples were analyzed by X-ray photoelectron spectroscopy to determine changes in the abundance and forms of sulfur, chlorine, oxygen, and nitrogen moieties as a result of interactions of flue gas components on the activated carbon surface during the sorption process. The data are best explained by a competition between the bound hydrogen chloride (HCl) and increasing sulfur [S(VI)] for a basic carbon binding site. Because loss of HCl is also coincident with Hg breakthrough or loss of the divalent Hg ion (Hg2+), the competition of Hg2+ with S(VI) on the basic carbon site is also implied. Thus, the role of the acid gases in Hg capture and release can be explained.  相似文献   

15.
Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg2+ to Hg0 was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg2+ with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg2+ sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of contaminated sites are discussed.  相似文献   

16.
17.
This study was undertaken to evaluate the biosorption potential of a natural, low-cost biosorbent, Rambai leaves (Baccaurea motleyana), to remove trace amounts of Hg(II) from aqueous solutions. It was found that the amount of Hg(II) biosorption by Rambai leaves increased with initial metal ion concentration, contact time, and solution pH but decreased as the amount of biosorbent increased. The maximum biosorption capacity was 121.95 mg/g for an initial concentration range of 5 to 120 ppb. Overall, kinetic studies showed that the Hg(II) biosorption process followed pseudo-second-order kinetics based on pseudo-first-order and intraparticle diffusion models. Isotherm data revealed that the biosorption process followed both Freundlich and Langmuir isotherms. The value of separation factor, R(L), from the Langmuir equation and rate of biosorption, n, from the Freundlich model also indicated favorable adsorption.  相似文献   

18.
In this present study, the biosorption of Cr(VI) and Zn(II) ions from synthetic aqueous solution on defatted J atropha oil cake (DJOC) was investigated. The effect of various process parameters such as the initial pH, adsorbent dosage, initial metal ion concentration and contact time has been studied in batch-stirred experiments. Maximum removal of Cr(VI) and Zn(II) ions in aqueous solution was observed at pH 2.0 and pH. 5.0, respectively. The removal efficiency of Cr(VI) and Zn(II) ions from the aqueous solution was found to be 72.56 and 79.81 %, respectively, for initial metal ion concentration of 500 mg/L at 6 g/L dosage concentration. The biosorbent was characterized by Fourier transform infrared, scanning electron microscopy and zero point charge. Equilibrium data were fitted to the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models and the best fit is found to be with the Freundlich isotherm for both Cr(VI) and Zn(II) metal ions. The kinetic data obtained at different metal ion concentration have been analysed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models and were found to follow the pseudo-second-order kinetic model. The values of mass transfer diffusion coefficients (D e) were determined by Boyd model and compared with literature values. Various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were analysed using the equilibrium constant values (K e) obtained from experimental data at different temperatures. The results showed that biosorption of Cr(VI) and Zn(II) ions onto the DJOC system is more spontaneous and exothermic in nature. The results indicate that DJOC was shown to be a promising adsorbent for the removal of Cr(VI) and Zn(II) ions from aqueous solution.  相似文献   

19.
The effective disposal of redundant elephant dung (ED) is important for environmental protection and utilization of resource. The aim of this study was to remove a toxic-azo dye, Reactive Red (RR) 120, using this relatively cheap material as a new adsorbent. The FTIR–ATR spectra of ED powders before and after the sorption of RR 120 and zero point charge (pHzpc) of ED were determined. The sorption capacity of ED for removing of RR 120 were carried out as functions of particle size, adsorbent dose, pH, temperature, ionic strength, initial dye concentration, and contact time. Sorption isotherm, kinetic, activation energy, thermodynamic, and desorption parameters of RR 120 on ED were studied. The sorption process was found to be dependent on particle size, adsorbent dose, pH, temperature, ionic strength, initial dye concentration, and contact time. FTIR–ATR spectroscopy indicated that amine and amide groups have significant role on the sorption of RR 120 on ED. The pHzpc of ED was found to be 7.3. Sorption kinetic of RR 120 on ED was well described by sigmoidal Logistic model. The Langmuir isotherm was well fitted to the equilibrium data. The maximum sorption capacity was 95.71 mg?g?1. The sorption of RR 120 on ED was mainly physical and exothermic according to results of DR isotherm, Arrhenius equation, thermodynamic, and desorption studies. The thermodynamic parameters showed that this process was feasible and spontaneous. This study showed that ED as a low-cost adsorbent had a great potential for the removal of RR 120 as an alternative eco-friendly process.  相似文献   

20.
The aim of this investigation was to obtain the hybrid material precursor to the naturally and abundantly available sericite, a mica-based clay; the materials were further employed in the remediation of arsenic from aqueous solutions. The study was intended to provide a cost-effective and environmentally benign treatment technology. The hybrid organo-modified sericite was obtained using hexadecyltrimethylammonium bromide (HDTMA) and alkyldimethylbenzylammonium chloride (AMBA) organic surfactants by introducing regulated doses of HDTMA or AMBA. The materials were characterized using infrared and X-ray diffraction analytical data, whereas the surface morphology was discussed by taking its SEM images. These materials were employed to assess the pre-concentration and speciation of As(III) and As(V) from aqueous solutions. The batch reactor data showed that increasing the sorptive concentration (from 1.0 to 15.0 mg/L) and pH (i.e., pH 2.0 to 10.0) caused the percent uptake of As(III) and As(V) to decrease significantly. The kinetic data showed that a sharp initial uptake of arsenic reached its equilibrium state within about 50 min of contact time, and the sorption kinetics followed a pseudo-second-order rate law both for As(III) and As(V) sorption. A 1,000 times increase in the background electrolyte concentration, i.e., NaNO3, caused a significant decrease in As(III) removal, whereas As(V) was almost unaffected, which inferred that As(III) was adsorbed, mainly by the van der Waals or even by the electrostatic attraction, whereas As(V) was adsorbed chemically and formed “inner-sphere” complexes at the solid/solution interface. The equilibrium state modeling studies indicated that the sorption data fitted well the Freundlich and Langmuir adsorption isotherms. Henceforth, the removal capacity was calculated under these equilibrium conditions. It was noted that organo-modified sericite possessed a significantly higher removal capacity compared to its virgin sericite. Between these two organo-modified sericite, the HDTMA-modified sericite possessed a higher removal capacity compared to the AMBA-modified sericite.  相似文献   

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