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1.
Biofilms wasted from biotrickling filters was dried and used as biosorbent for Cd(II) removal from aqueous solutions. The adsorption condition and effect, adsorption isotherms and kinetics of Cd(II) removal were investigated, and the effects of competitive metal ions on Cd(II) removal were also examined. Results showed that the dry waste biofilms reached the maximum adsorption capacity of 42 mg/g of Cd(II) at 25 °C for 120 min when the initial concentration of Cd(II) and their pH were 50 mg/L and 6.0, respectively. Under these conditions, the removal efficiency of Cd(II) reached to 89.3% when the biosorbent dosage was 2.0 g/L. The Langmuir isotherm model correlated with the isotherm data better than the Freundlich isotherm model, and the pseudo-second-order model fitted the kinetic data better than the pseudo-first-order model. These results indicated that the adsorption was monolayer accompanied with chemical adsorption. In the presence of other metal ions, divalent metal ions of Ca and Zn inhibited the performance of Cd(II) biosorption significantly, while Na(I), K(I) and Fe(III) which had a higher or lower valence than Ca(II) affected slightly when containing 50 mg/L Cd(II), 0.5 g/L adsorbent dosage and pH 6.0. The analyses of scanning electron microscopy and Fourier transform infrared spectroscopy illuminated that the biosorbent had porous structures and the amide group was the majorly responsible for Cd(II) removal. Dry biofilms were novel sorbents for effective removal Cd(II), and it could be reused and recycled if necessary.  相似文献   

2.
In this study, sepiolite-nano zero valent iron composite was synthesized and applied for its potential adsorption to remove phosphates from aqueous solution. This composite was characterized by different techniques. For optimization of independent parameters (pH = 3–9; initial phosphate concentration = 5–100 mg/L; adsorbent dosage = 0.2–1 g/L; and contact time = 5–100 min), response surface methodology based on central composite design was used. Adsorption isotherms and kinetic models were done under optimum conditions. The results indicated that maximum adsorption efficiency of 99.43 and 92% for synthetic solution and real surface water sample, respectively, were achieved at optimum conditions of pH 4.5, initial phosphate concentration of 25 mg/L, adsorbent dosage of 0.8 g/L, and 46.26 min contact time. The interaction between adsorbent and adsorbate is better described with the Freundlich isotherm (R 2 = 0.9537), and the kinetic of adsorption process followed pseudo-second-order model. Electrostatic interaction was the major mechanisms of the removal of phosphates from aqueous solution. The findings of this study showed that there is an effective adsorbent for removal of phosphates from aqueous solutions.  相似文献   

3.
Thermally carbonization biochar produced from a traditional Chinese herbal medicine waste (Astragalus mongholicus residue) was investigated for its performance in ciprofloxacin adsorption. Batch sorption experiments were conducted, and scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller surface area analyses were employed to characterize the biochar. The results demonstrated that thermal activation process improves the adsorbent characteristics. Biochar produced at 800 °C had the best adsorption capacity, a better pore structure and the largest surface areas. The adsorption process fit well to a pseudo-second-order kinetics model. The adsorption isothermal model results revealed that the adsorption process of ciprofloxacin is described better by the Freundlich isotherm and the type of adsorption is a chemical process. The maximum adsorption of ciprofloxacin occurred at pH 7. The present research demonstrated that A. mongholicus biochar might be an attractive and cost-effective adsorbent with good adsorption performance for removing ciprofloxacin from water solution.  相似文献   

4.
In this research, the stems of Onopordom Heteracanthom which is a kind of weed were converted to biochar particles, and their characteristics were investigated. The morphology and purity of these particles were examined by SEM and EDX techniques, respectively. Specific surface area was obtained as 5.73 m2 g?1 by BET method. The biochar particles obtained from Onopordom Heteracanthom were evaluated as an adsorbent to remove Cr(VI) from aqueous environments. The effect of some parameters such as initial concentration of Cr(VI), dosage of adsorbent, and pH were investigated on the adsorption capacity of Cr(VI) onto the adsorbent. The equilibrium data were analyzed by various isotherm models. The results revealed that in this process, the adsorption isotherm and kinetics have more conformity with Langmuir isotherm and pseudo-second-order kinetics, respectively. The multi-linearity of the Weber and Morris adsorption kinetic model indicates that the intra-particle diffusion is not merely the rate-controlling step for the whole adsorption process.  相似文献   

5.
Nonlinear kinetic analysis of phenol adsorption onto peat soil   总被引：1，自引：0，他引：1  
Phenolic compounds are considered as a serious organic pollutant containing in many industrial effluents particularly vulnerable when the plant discharge is disposed on land. In the present study, the phenol removal potential of peat soil as adsorption media was investigated as the adsorption process are gaining popular for polishing treatment of toxic materials in industrial wastewater. Batch experiments were performed in the laboratory to determine the adsorption isotherms of initial concentrations for 5, 8, 10, 15, and 20 mg/L and predetermined quantity of peat soil with size ranges between 425 and 200 μm poured into different containers. The effects of various parameters like initial phenol concentration, adsorbent quantity, pH, and contact time were also investigated. From experimental results, it was found that 42 % of phenol removal took place with optimized initial phenol concentration of 10 mg/L, adsorbent dose of 200 g/L, solution pH 6.0 for the equilibrium contact time of 6 h. The result exhibits that pseudo-first-order (R 2 = 0.99) and Langmuir isotherm models are fitted reasonably (R 2 = 0.91). Adams–Bohart, Thomas, Yoon–Nelson, and Wolborska models were also investigated to the column experimental data of different bed heights to predict the breakthrough curves and to determine the kinetic coefficient of the models using nonlinear regression analysis. It was found that the Thomas model is the best fitted model to predict the experimental breakthrough curves with the highest coefficient of determination, R 2 = 0.99 and lowest root mean square error and mean absolute performance error values.  相似文献   

6.
Hexavalent chromium has been proved to be the reason of several health hazards. This study aimed at evaluating the application of pomegranate seeds powder for chromium adsorption (VI) from aqueous solution. Chromium adsorption percentage (VI) increased with increasing the adsorbent dosage. Chromium adsorption capacity (VI), at pH = 2 and 10 mg/L initial metal concentration, decreased from 3.313 to 1.6 mg/g through increasing dosage of adsorbent from 0.2 to 0.6 g/100 ml. The adsorption rate increased through increase in chromium initial concentration (VI). However, there was a removal percentage reduction of chromium (VI). Chromium adsorption kinetics by different models (pseudo-first-order, modified pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion, Boyd kinetic) was investigated as well. Studies on adsorption kinetic indicated that the experimental data were matched by pseudo-second-order model (R 2 = 0.999) better. Obtained results demonstrated the pomegranate seeds can be used as an effective biomaterial and biosorbent for hexavalent chromium adsorption from aqueous solutions.  相似文献   

7.
In this study, the feasibility of using a low-cost adsorbent mixture composed of leonardite (L) and clinoptilolite (C) was evaluated by batch adsorption method using different parameters such as mixing ratio, contact time, pH, temperature, and adsorbent amount for the removal of Zn (II) ions from an aqueous solution. The adsorbents were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Additionally, leonardite–clinoptilolite mixture was analyzed by scanning electron microscopy coupled with energy dispersive X-ray. The Zn (II) adsorption along with an unprecedented adsorption capacity of 454.55 mg g?1 for unmodified natural sorbents was obtained by mixing leonardite and clinoptilolite (LC) without any pretreatment at a ratio of 3:1, using 0.1 g of sorbent at a pH 6, for 2 h of contact time. The experimental data showed a good fit for the Langmuir isotherm model. The thermodynamic parameters revealed that the present adsorption process was spontaneous and exothermic in nature (25–50 °C). The kinetic results of the adsorption showed that the Zn (II) adsorption onto the LC follows pseudo-second-order model. The resultant LC mixture has an excellent adsorption capacity of a Zn (II) aqueous solution, and data obtained may form the basis for utilization of LC as an unpretreated low-cost adsorbent for treatment of metalliferous industrial wastewater.  相似文献   

8.
In this work, a low-cost lignocellulosic adsorbent with high biosorption capacity is proposed, suitable for the efficient removal of hexavalent chromium from water and wastewater media. The adsorbent was produced by autohydrolyzing Scots Pine (Pinus Sylvestris) sawdust. The effect of the autohydrolysis conditions, i.e., pretreatment time and temperature, on hexavalent chromium biosorption was investigated using energy-dispersive X-ray spectroscopy (EDS) and UV–visible spectrophotometry. The Freundlich, Langmuir, Sips, Radke-Prausnitz, Modified Radke-Prausnitz, Tóth, UNILAN, Temkin and Dubinin-Radushkevich adsorption capacities and the rate constant values for pseudo-first- and pseudo-second-order kinetics indicated that the autohydrolyzed material exhibits significantly enhanced hexavalent chromium adsorption properties comparing with the untreated sawdust. The Freundlich’s adsorption capacity K F increased from 2.276 to 8.928 (mg g?1)(L mg?1)1/n , and the amount of hexavalent chromium adsorbed at saturation (Langmuir constant q m) increased from 87.4 to 345.9 mg g?1, indicating that autohydrolysis treatment at 240 °C for 50 min optimizes the adsorption behavior of the lignocellulosic material.  相似文献   

9.
The functionalized nano-clay composite adsorbent was prepared, and its properties were characterized using FT-IR, XRD and SEM techniques. The synthesized nano-clay composite was studied with regard to its capacity to remove ibuprofen under different adsorption conditions such as varying pH levels (5–9), initial ibuprofen concentrations (3, 5 and 10 mg L?1), contact time, and the amount of adsorbent (0.125, 0.25, 0.5 and 1 g). In order to evaluate the nanocomposite adsorption capacity, the adsorption results were assessed using nine isotherm models. The results showed that the optimum adsorption pH was 6 and that an increase or decrease in the pH reduced the adsorption capacity. The adsorption process was fast and reached equilibrium after 120 min. The maximum efficacy of ibuprofen removal was approximately 95.2%, with 1 g of adsorbent, 10 mg L?1 initial concentration of ibuprofen, 120 min contact time and pH = 6. The optimal adsorption isotherm models were the Freundlich, Fritz–Schlunder, Redlich–Peterson, Radke–Prausnitz, Sip, Toth and Khan models. In addition, four adsorption kinetic models were employed for adsorption system evaluation under a variety of experimental conditions. The kinetic data illustrated that the process is very fast, and the reaction followed the Elovich kinetic model. Therefore, this nano-clay composite can be used as an effective adsorbent for the removal of ibuprofen from aqueous solutions, such as water and wastewater.  相似文献   

10.
Bimetallic Fe/Ni nanoparticles were synthesized and used for the removal of profenofos organophosphorus pesticide from aqueous solution. These novel bimetallic nanoparticles (Fe/Ni) were characterized by scanning electron microscopy, energy-dispersive X-ray analysis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The effect of the parameters of initial pesticide concentration, pH of the solution, adsorbent dosage, temperature, and contact time on adsorption was investigated. The adsorbent exhibited high efficiency for profenofos adsorption, and equilibrium was achieved in 8 min. The Langmuir, Freundlich, and Temkin isotherm models were used to determine equilibrium. The Langmuir model showed the best fit with the experimental data (R 2 = 0.9988). Pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were tested to determine absorption kinetics. The pseudo-second-order model provided the best correlation with the results (R 2 = 0.99936). The changes in the thermodynamic parameters of Gibb’s free energy, enthalpy, and entropy of the adsorption process were also evaluated. Thermodynamic parameters indicate that profenofos adsorption using Fe/Ni nanoparticles is a spontaneous and endothermic process. The value of the activation energy (E a = 109.57 kJ/mol) confirms the nature of the chemisorption of profenofos onto Fe/Ni adsorbent.  相似文献   

11.
Metal-complex dyes are widely used in textile industry, but harmful to the environment and human health due to aromatic structure and heavy metal ions. The objective of this work was to evaluate the adsorption potential of bamboo biochar for the removal of metal-complex dye acid black 172 from solutions. Freundlich model was more suitable for the adsorption process of bamboo biochar than Langmuir isotherm, indicating multilayer adsorption of acid black 172 on a heterogeneous bamboo biochar surface. Adsorption kinetics analysis of pseudo-second-order and Weber–Morris models revealed that intraparticle transport was not the only rate-limiting step. The bamboo biochar exhibited a good adsorption performance even at high ionic strength. Analysis based on the artificial neural network indicated that the temperature with a relative importance of 29 % appeared to be the most influential parameter in the adsorption process for dye removal, followed by time, ionic strength, pH and dye concentration.  相似文献   

12.
Atomic layer deposition (ALD) thin film coating was applied to improve the hydrophilia of biochar derived from black willow. 2 (2Al, 0.82 wt% Al2O3), 5 (5Al, 1.40 wt% Al2O3), and 10 (10Al, 2.36 wt% Al2O3) cycles of alumina ALD were applied. The biochars were characterized by inductively coupled plasma–atomic emission spectroscopy, nitrogen adsorption and desorption, scanning electron microscopy, and Fourier transform infrared spectroscopy. The adsorbents were utilized for the removal of methylene blue (MB) from an aqueous solution to evaluate their adsorption capacities. The 5Al biochar showed the highest adsorption capacity, compared to the uncoated biochar and other Al2O3 coated biochars, due to its improved hydrophilia. The amount of MB adsorbed onto the 5Al biochar was almost three times that adsorbed onto the uncoated biochar during the first hour of adsorption experiments. Adsorption isotherms were modeled with the Langmuir and Freundlich isotherms. The data fit well with the Langmuir isotherm, and the maximum adsorption capacities were found to be 26.8 and 35.0 mg/g at 25 °C for the uncoated biochar and 5Al biochar, respectively. The adsorbed MB amount per square meter achieved 1.3 mg/m2 onto the 5Al biochar, and it was twice the amount on the uncoated biochar. The experimental data were analyzed by pseudo-first-order and pseudo-second-order kinetics models of adsorption. The pseudo-second-order model better describes adsorption kinetic data for the uncoated biochar and 5Al biochar than the pseudo-first-order model does.  相似文献   

13.
In this research, ordered mesoporous silica, including MCM-41, was synthesized via sol–gel process and a propyl methacrylate-modified ordered mesoporous silica (MPS-MCM-41) was successfully synthesized via a postsynthesis grafting process. Then both MCM-41 and MPS-MCM-41 were characterized using FTIR, XRD, SEM and BET techniques. The synthesized materials were utilized as adsorbent for removal of diazinon pesticide from aqueous solutions. The effects of pH, contact time, adsorbent dose, initial concentration and temperature have been evaluated using removal efficiencies. Also, the kinetic, thermodynamic and isotherm models of diazinon adsorption were studied for the both MCM-41 and MPS-MCM-41. The results showed that the maximum adsorption capacities are 142 and 254 mg g?1 for the MCM-41 and MPS-MCM-41, respectively, at the initial concentration of 50 mg L?1, temperature of 298 K and adsorbent dose of 0.1 g L?1. The highest percentages of diazinon removal are 56.4 and 87.2 (at adsorbent dose of 2 g L?1 and the temperature of 318 K) for the MCM-41 and MPS-MCM-41, respectively. The Freundlich and Langmuir models are more compatible for describing equilibrium data of the diazinon adsorption capacity on the MCM-41 and MPS-MCM-41, respectively. Thermodynamic study indicated that the adsorption process of diazinon onto MCM-41 and MPS-MCM-41 is exothermic and has a spontaneous nature. The higher adsorption capacity and higher spontaneous nature of MPS-MCM-41 in comparison with MCM-41 might be due to the presence of the both hydrogen bonding and hydrophobic interaction between surface functional groups of MPS-MCM-41 (hydroxyl and propyl methacrylate) and diazinon functional groups.  相似文献   

14.
In the present study, adsorption of lead (II) ions from aqueous solution by alluvial soil of Bhagirathi River was investigated under batch mode. The influence of solution pH, sorbent dose, initial lead (II) concentration, contact time, stirring rate and temperature on the removal process were investigated. The lead adsorption was favored with maximum adsorption at pH 6.0. Sorption equilibrium time was observed in 60 min. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir, Dubinin–Radushkevich and Temkin adsorption isotherm models. The kinetics of lead (II) ion was discussed by pseudo first-order, pseudo second-order, intra-particle diffusion, and surface mass transfer models. It was shown that the adsorption of lead ions could be described by the pseudo second-order kinetic model. The activation energy of the adsorption process (E a) was found to be ?38.33 kJ mol?1 using the Arrhenius equation, indicating exothermic nature of lead adsorption onto alluvial soil. Thermodynamic parameters, such as Gibbs free energy (?G 0), the enthalpy (?H 0), and the entropy change of sorption (?S 0) have also been evaluated and it has been found that the adsorption process was spontaneous, feasible, and exothermic in nature. The results indicated that alluvial soil of Bhagirathi River can be used as an effective and low cost adsorbent to remove lead ions from aqueous solutions.  相似文献   

15.
This work aimed to investigate the adsorption characteristics, both kinetically and thermodynamically, of Cu(II) and Pb(II) removal from aqueous solutions onto mixed-waste activated carbon, as well as to study the competitive behavior found in mixed heavy metal solution systems. This study shows that activated carbon prepared from mixed waste is an effective adsorbent for the removal of Cu(II) and Pb(II) from aqueous solutions, with the aim of detoxifying industrial effluents before their safe disposal onto water surfaces. The adsorption process was characterized in terms of kinetic and thermodynamic studies. In addition, the influence of presence of Cu(II) and Pb(II) in a competitive system was investigated. The results showed that the maximum adsorption capacities were gained at a pH of 6 with a contact time of 180 min, a metal solution concentration of 300 ppm, and an adsorbent dose of 0.3 g/L. The adsorption process was found to follow a pseudo-first-order kinetic model. Thermodynamic parameters such as ΔG o, ΔH o, and ΔS o showed that the sorption process was spontaneous and endothermic in nature. A competitive study demonstrated the applicability of mixed-waste activated carbon to adsorb Cu(II) and Pb(II) from a solution of mixed metals. In addition, the adsorption capacity was found to be as effective as other adsorbents reported in the literature. The developed adsorptive removal procedure was applied for treatment of real wastewater samples and showed high removal efficiency.  相似文献   

16.
Sewage treatment station in oilfield needs a new process to meet the desired requirements. A new process was proposed to meet the discharge standards, which consisted of the following sub-processes: electrochemical treatment → coagulation treatment → integrated biochemical treatment of moving bed biofilm reactor and membrane bio-reactor → combined treatment process of macroporous adsorption resin. Electrochemical treatment included 5 electrolytic cells, total volume of which was 10 L. The PFS was chosen as the coagulants in the coagulation treatment, and the removal rate of COD could reach 66% when the dosage of PFS was 500 mg/L. The biochemical treatment consisted of anoxic tank, aerobic tank and membrane zone, and the removal rate of COD was about 55–70% when HRT was 12 h. SD300 resin was chosen as the best adsorbent in the treatment using macroporous adsorption resin. In addition, the effluent COD after coagulation treatment process becomes about 180 mg/L, the effluent COD after biological treatment becomes about 50 mg/L, and the last effluent COD with the macroporous adsorption resin becomes about 20 mg/L. The three-dimensional fluorescence spectrum was used to analyze the differences in types of organic matters in water samples between the raw water and the treated one. The results demonstrated that the new process meets the needs of wastewater treatment.  相似文献   

17.
This study assesses the ability of two low-cost adsorbents made from waste of Rapanea ferruginea treated with ethanol (WRf) and its H2SO4-treated analog (WRf/H2SO4) for the removal of two cationic dyes methylene blue (MB) and crystal violet (CV) from aqueous solutions. The adsorbent was characterized by scanning electron microscopy, Fourier transform infrared spectrometry, thermogravimetric analysis, point of zero charge (pHpzc), specific surface, and functional groups. The adsorption of dye onto the adsorbents was studied as a function of pH solution (2–12), contact time (up to 120 min) and initial concentration (20–120 mg/L), and temperature (25, 35, and 55 °C). The influence of these parameters on adsorption capacity was studied using the batch process. The response surface methodology (RSM) was used in the experimental design, modeling of the process, and optimizing of the variables and was optimized by the response involving Box–Behnken factorial design (15 runs). The results show that the data correlated well with the Sips isotherm. The maximum adsorption capacities of MB and CV onto WRf were found to be 69 and 106 mg/g, and onto WRf/H2SO4, the adsorption capacities were 33 and 125 mg/g, respectively. The kinetic data revealed that adsorption of cationic dyes onto the adsorbents closely follows the pseudo-second-order kinetic model. Regression analysis showed good fit of the experimental data to the second-order polynomial model, with coefficient of determination (R2) values for MB (R2?=?0.9685) and MB (R2?=?0.9832) for WRf and CV (R2?=?0.9685) and CV (R2?=?0.9832) for WRf/H2SO4 indicated that regression analysis is able to give a good prediction of response for the adsorption process in the range studied. The results revealed that waste from R. ferruginea is potentially an efficient and low-cost adsorbent for adsorption of MB and CV.  相似文献   

18.
The main objective of this study is to investigate the possibility of powdered eggshell used as an adsorbent material for removal of humic acid from peat water. The influences of contact time, dose of eggshells, pH, and temperature were the factors considered in the removal processes of humic acid from peat water. In addition, adsorption isotherms of humic acid onto the powdered eggshell were also evaluated with the Langmuir and Freundlich approximations. Our results showed that the equilibrium of the process was eventually established after 60 min of the contact time, and also found that using 5 g of the powdered eggshell nearly 95 % of humic acid has been successfully removed from the peat water. The removal of humic acid gave better result when it was conducted at low pH, and it was almost unaffected the temperatures variation. The data was well fitted to Freundlich isotherm with the correlation coefficient of not <0.999, and could uptake the humic acid about 126.58 mg/g at pH 4.01, estimated from the Langmuir model. The kinetic experimental data proportionally correlated with the pseudo-second-order kinetic model with a rate constant in the range of 0.016–0.112 g mg?1 min?1, while intra-particle-diffusion were the main rate determining step in the humic acid removal process. The powdered eggshell investigated in this study, thus, exhibited as a high potential adsorbent for the removal of humic acid from peat water.  相似文献   

19.
A novel polyurethane foam/organobentonite/iron oxide nanocomposite adsorbent was successfully prepared via in situ polymerization of toluene diisocyanate and polyol in presence of 5 wt% organobentonite/iron oxide. The obtained nanocomposite was characterized in detail, and the results revealed that the clay layers are exfoliated and/or intercalated in the polymer matrix forming a nanocomposite structure. The application of the prepared nanocomposite for adsorption of cadmium ions from aqueous solution was tested as a function of various experimental parameters using batch procedures. Adsorptive removal of Cd(II) onto the nanocomposite attained maximum at adsorbent content 1.5 g/L, pH 6, and the equilibrium was established within 60 min. Kinetic studies showed that the experimental data fit very well to pseudo-second-order model, and the adsorption process proceeds through three steps. It was found that external liquid film and intraparticle diffusion steps deeply affect the rate of Cd2+ ions adsorption onto the synthesized nanocomposite. Langmuir isotherm model fitted the adsorption data better than Freundlich with a maximum adsorption capacity (q m) for Cd(II) equal to 78 mg/g under the specified experimental conditions. The synthesized nanocomposite afforded effective extraction for Cd2+ ions from natural water samples and excellent reusability feature. This study declares the potential efficiency of a new clay/polymer nanocomposite as alternative for wastewater remediation.  相似文献   

20.
Abundantly available agricultural waste materials (banana bunch, sorghum stem and casuarinas fruit) are processed with negligible cost and are found to be highly suitable as biosorbents for chromium(VI) removal from aqueous environment due to high surface area and functional groups of adsorbents. The equilibrium data have been analyzed for the adsorbate–adsorbate/adsorbent interactions and found to be fitted to the data in the order, Hill–de Boer ≥ Fowler–Guggenheim ? Frumkin > Kiselev. To determine the characteristic parameters for process design, mass transfer studies have been carried out using two-parameter isotherm models (Harkins–Jura, Halsey, Smith, El-Awady and Flory–Huggins) and three-parameter isotherm models (Redlich–Peterson and Sips) which are applied to the experimental data. The fitness of the isotherms describes that both mono- and multilayer adsorptions occur in the present studied three biosorbents in preference to the latter. The mechanism of adsorption has been studied using diffusion kinetic models (viz. liquid film diffusion, Dunwald–Wagner intra-particle diffusion model and moving boundary model) and described the possibility of diffusion in the order of banana bunch–stem powder > sorghum stem powder > casuarinas fruit powder in terms of diffusion coefficients. In essence of all the results, the selected adsorbents can be used as a potential adsorbent for the removal of Cr(VI) from aqueous solutions.  相似文献   

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