Removal of Cr(VI) from Water Using Attapulgite/Chitosan Composites

2013 ◽  
Vol 781-784 ◽  
pp. 2233-2236
Author(s):  
Yong Chen ◽  
Shi Yu Wang ◽  
Hui Xu

In this work attapulgite and chitosan were employed to prepare composites as eco-friendly adsorbent. Study on the adsorption efficiency of the adsorbent for Cr (VI) in aqueous solution was carried out. External factors such as the amount of attapulgite in the composites, initial concentration of Cr (VI), adsorption time and adsorbent dosage how to influence the adsorption efficiency of composites were investigated. The results showed that 0.63g adsorbent can reach maximum adsorption rate, which the mass ratio of attapulgite and chitosan is 0.8:1, the initial concentration of copper ions is 100mg / L and absorption time is 30min. Isotherm data fitted well to the Langmuir isotherm model.

2012 ◽  
Vol 499 ◽  
pp. 419-422
Author(s):  
Yong Chen ◽  
Hui Xu ◽  
Jin Bao Sun ◽  
Chang Long Zhang

In this work attapulgite and chitosan were employed to prepare composites as eco-friendly adsorbent. Study on the removal efficiency of the adsorbent for copper ions in aqueous solution was carried out. External factors such as the amount of attapulgite in the composites, temperature, initial concentration of copper ions, adsorption time and adsorbent dosage how to influence the removal efficiency of composites were investigated. The results showed that at room temperature, 0.37g adsorbent can reach maximum adsorption rate, which the mass ratio of attapulgite and chitosan is 1:1, the initial concentration of copper ions is 50mg / L and absorption time is 2h.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3150
Author(s):  
Mengwei Xu ◽  
Chao Huang ◽  
Jing Lu ◽  
Zihan Wu ◽  
Xianxin Zhu ◽  
...  

Magnetic MXene composite Fe3O4@Ti3C2 was successfully prepared and employed as 17α-ethinylestradiol (EE2) adsorbent from water solution. The response surface methodology was employed to investigate the interactive effects of adsorption parameters (adsorption time, pH of the solution, initial concentration, and the adsorbent dose) and optimize these parameters for obtaining maximum adsorption efficiency of EE2. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Optimization of the process variables for maximum adsorption of EE2 by Fe3O4@Ti3C2 was performed using the quadratic model. The model predicted maximum adsorption of 97.08% under the optimum conditions of the independent variables (adsorption time 6.7 h, pH of the solution 6.4, initial EE2 concentration 0.98 mg L−1, and the adsorbent dose 88.9 mg L−1) was very close to the experimental value (95.34%). pH showed the highest level of significance with the percent contribution (63.86%) as compared to other factors. The interactive influences of pH and initial concentration on EE2 adsorption efficiency were significant (p < 0.05). The goodness of fit of the model was checked by the coefficient of determination (R2) between the experimental and predicted values of the response variable. The response surface methodology successfully reflects the impact of various factors and optimized the process variables for EE2 adsorption. The kinetic adsorption data for EE2 fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Therefore, Fe3O4@Ti3C2 composite present the outstanding capacity to be employed in the remediation of EE2 contaminated wastewaters.


2021 ◽  
Vol 13 (23) ◽  
pp. 13264
Author(s):  
A. A. Oyekanmi ◽  
Akil Ahmad ◽  
Siti Hamidah Mohd Setapar ◽  
Mohammed B. Alshammari ◽  
Mohammad Jawaid ◽  
...  

This investigation reports on the biosorption mechanism of Congo Red dyes (CR) in aqueous solution using acid-treated durian peels, prepared for this study. The biosorbent nature was characterized using the Scanning Electron Microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and Brunaure-Emmet-Teller (BET). The effect of process parameters within operational range of pH (2–9), contact time (10–200 min), initial concentration (25–400 mg g−1) and temperature (25–65 °C) for the optimum removal of CR dyes was investigated using central composite design (CCD) under response surface methodology (RSM), and revealed that the optimum condition of biosorption was achieved around a pH of 5.5, contact time of 105 min at initial concentration of 212.5 mg L−1 within 45 °C temperature, which corresponds to 95.2% percent removal of CR. The experimental data fitted better to the second order polynomial model, with a correlation coefficient R2 value of 0.9917 and the Langmuir isotherm model with biosorption capacity of 107.52 mg g−1. Gibbs free energy indicated that the adsorption of CR dyes was spontaneous. The mechanism of the adsorption of CR dyes revealed that the biosorption of CR dyes investigated under different operational conditions show that under acidic pH, the adsorption efficiency of the acid treated durian peels is enhanced for the adsorption of CR dye molecules.


2007 ◽  
Vol 124-126 ◽  
pp. 1781-1784 ◽  
Author(s):  
Yongju Jung ◽  
Jei Won Yeon ◽  
Ji Man Kim ◽  
Hyung Ik Lee ◽  
Seok Kim ◽  
...  

In this study, we modified the surface of nanoporous carbons with carboxymethylated polyethyleneimine (CM-PEI) of a high charge density in order to increase the Pt loading on the nanoporous carbons in an aqueous solution. We carried out equilibrium adsorption tests of Pt(IV) on the pure nanoporous carbon and the CM-PEI-coated carbons and evaluated the adsorption isotherm on the CM-PEI-coated carbon using various isotherm models. It was found that the adsorption of Pt(IV) onto the CM-PEI-coated carbons obeys the Langmuir isotherm model.


2012 ◽  
Vol 535-537 ◽  
pp. 2365-2369 ◽  
Author(s):  
Ji Lei Wang ◽  
Ming Hui Li ◽  
Li Gang Wei ◽  
Ying Chong Ma ◽  
Kun Lan Li ◽  
...  

Biodegradable cellulose/collagen beads were successfully prepared by coagulating a blend of cellulose and collagen using 1–butyl–3–methylimidazolium chloride ([C4mim]Cl). The copper ions (Cu(II)) adsorption from aqueous solutions using the prepared beads were investigated at 15 °C as a function of initial concentrations, adsorbents types and adsorption time. The results show that Cu(II) adsorption amount increases with increasing initial concentration. Cellulose/collagen beads can absorb more Cu(II) than cellulose beads and the adsorption equilibrium can be achieved at 30 min. The maxinum adsorption amount of the cellulose/collagen beads (1/1, wt/wt) is estimated to be 0.51 mmol/g. The 90% absorbed Cu(II) on the composite beads can be desorbed by treating with 1 mol/L HCl solution for 180 min.


2014 ◽  
Vol 931-932 ◽  
pp. 178-182
Author(s):  
Nusavadee Pojananukij ◽  
Kitirote Wantala ◽  
Sutasinee Neramittagapong ◽  
Arthit Neramittagapong

The adsorption efficiency of As (V) ions from an aqueous solution was investigated. The adsorption experiments were carried out in a batch reactor. The effects of operating parameters; i.e. the absorbent dose (g/L), the pH, the adsorption temperature (°C), the As (V) initial concentration (ppb), and type of adsorbents, on the adsorption efficiencies were studied. A PlackettBurman experimental design was used to screen for the important factors that influence As (V) adsorption. It has been found that the most important effect on the As (V) adsorption capacity was the type of adsorbent. The factor importance could be written in descending order as follows: the type of adsorbents, the adsorbent dose, the As (V) initial concentration, the adsorption temperature, and the pH.


2012 ◽  
Vol 588-589 ◽  
pp. 47-50
Author(s):  
Ze Sheng Cheng ◽  
Zhen Wang ◽  
Yu Liu ◽  
Na Na Bo

Alkali lignin, Modification, Quaternary ammonium salt, Cr(Ⅵ), Anion adsorbent Abstract. LIA(lignin ionic adsorbent) was synthesized by modified alkali lignin after reaction with epichlorohydrin and dimethylamine or diethylamine by using the modifying agents of N-methylmorpholine (NMM) in the presence of organic medium of N,N-dimethylformamide(DMF). The LIA was characterized by FTIR spectroscopy and elements analysis, the yield of products and the adsorbent capabilities for Cr(Ⅵ) from aqueous solution were also exploited. The factors that might influent the adsorption performance were investigated, such as adsorption time, reagent dosage and the initial concentration of Cr(Ⅵ). It was found that the efficiency of Cr(Ⅵ) removal were better when the amount of the sorbent was increased. But the removal efficiency was reduced as the initial concentration of Cr(Ⅵ) increased. The contrast result of the two synthesis processes also proved the yields of sample 3 (modified alkali lignin using diethylamine) was higher than sample 2 (modified alkali lignin using dimethylamine). And the adsorption capabilities of sample 3 were also better than sample 2.


2012 ◽  
Vol 549 ◽  
pp. 318-321 ◽  
Author(s):  
Yong Hong Wu ◽  
Qi Yu ◽  
Hong Da Xu ◽  
Zhi Yong Liu ◽  
Ming Zhu Sun ◽  
...  

The adsorption behavior of methyl orange aqueous solution was investigated on husk-based activated carbon. The effects of key factors, i.e., degassing pretreatment, adsorption time, temperature, adsorbent dosage and initial concentration, on the adsorption efficiency were measured. The kinetic adsorption curves and adsorption isotherms were fitted with theoretical model. The results show that the removal efficiency of methyl orange could be significantly improved by degassing pretreatment, prolonging the time, lowering temperature or reducing the initial concentration. In the context, adsorption equilibrium will be achieved up 90min. Furthermore, adsorption rate will be enhanced by the increase of the amount of activated carbon. In conclusion, adsorption isotherm and adsorption kinetics can be fitted well with Freundlich equation and pseudo-first Lagergren model, respectively.


2020 ◽  
Author(s):  
Can Du ◽  
Jinsheng Wang ◽  
Xin Liu ◽  
Juanting Niu

&lt;p&gt;In this paper, six typical adsorption materials (activated carbon, kaolin, montmorillonite, bentonite, zeolite, and attapulgite) were used to investigate the effects of adsorption time, initial concentration, pH, and temperature on the adsorption of cesium (Cs) contained in wastewater. A combination of kinetics and isotherms was used. The results revealed that, for the same adsorption time, the adsorption efficiencies of the six materials for Cs were as follows: zeolite&gt;attapulgite&gt;bentonite&gt;montmorillonite&gt;activated carbon&gt;kaolin. The adsorption rate of zeolite to Cs ions was almost independent of the initial concentration and temperature. The removal effect of other materials improved in alkaline environments at 30&amp;#8451;. Attapulgite, montmorillonite, activated carbon, and kaolin could be used for the removal of Cs at low initial concentrations. The adsorptive processes utilized by the six adsorption materials were the result of a combination of various adsorption mechanisms. Among the six typical adsorption materials, zeolite, attapulgite, and bentonite had clear removal effects and could be used in practical application in which radioactive wastewater containing Cs needs to be disposed of. Our results suggest that zeolite is the best adsorption material for this purpose.&lt;/p&gt;


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
César Augusto Canciam ◽  
Nehemias Curvelo Pereira

Fruit consumption and processing result in considerable volumes of residual biomass. Transformation of this biomass into biosorbents offers an alternative for its reuse and disposal. As the green coconut shell is a waste often discarded in landfills and dumps, generating gases and leachate, two biosorbents were developed from the epicarp and mesocarp of green coconut to adsorb fluoride ions in aqueous solution. The kinetic experiments showed that sorption of fluoride ions reached equilibrium at 300 min for both epicarp and mesocarp at temperatures of 25°C, 35°C, and 45°C. The removal efficiency of fluoride ions varied from 66.25% (at 25°C) to 77.50% (at 45°C) for the epicarp and from 90% (at 25°C) to 97.50% (at 45°C) for the mesocarp. The thermodynamic parameters of the adsorption process showed that adsorption is a spontaneous, endothermic process for both biosorbents. The adsorption was classified as chemical, with the Langmuir isotherm model best suited to the adsorption isotherms data.


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