scholarly journals Adsorbing low concentrations of Cr(VI) onto CeO2@ZSM-5 and the adsorption kinetics, isotherms and thermodynamics

2018 ◽  
Vol 77 (9) ◽  
pp. 2327-2340 ◽  
Author(s):  
Jianrui Niu ◽  
Xiuxiu Jia ◽  
Yaqing Zhao ◽  
Yanfang Liu ◽  
Weizhang Zhong ◽  
...  
Keyword(s):  
Adsorption Kinetics ◽  
Photoelectron Spectroscopy ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
X Ray ◽  
Low Concentrations ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order ◽  
Isotherms And Thermodynamics ◽  
Kinetics Of

Abstract The CeO2@ZSM-5 was prepared by the dipping method. We used ZSM-5 and CeO2 as the carrier and load components, respectively. The aim was to reduce the low concentration of Cr(VI) in simulated wastewater (the concentration of Cr(VI) ranged from 0.2 to 1 mg/L). The characteristics of ZSM-5 and CeO2@ZSM-5 samples were determined by X-ray powder diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET). Characterization results showed that the particle size, BET surface area and pore volume for CeO2@ZSM-5 was around 0.783 nm, 421.307 m2/g and 0.313 m3/g, respectively. In addition, the optimum conditions were obtained by the orthogonal test, and the details were as follows: optimal pH, adsorbent dose, initial concentration of Cr(VI) and equilibrium time were 3, 5 g/L, 0.6 mg/L and 70 min respectively. The removal of Cr(VI) was 99.56% in these conditions. The pseudo-second-order model best described the adsorption kinetics of Cr(VI) onto CeO2@ZSM-5. Isotherm data were treated according to Langmuir, Freundlich and Temkin isotherm models. The results showed that the Freundlich adsorption isotherm model fitted best in the temperature range studied. Adsorption capacity increased with temperature, showing the endothermic nature of Cr(VI) adsorption. The desorption results showed the best recovery of Cr(VI) using 0.1 M HCl.

scholarly journals Enhanced removal of hexavalent chromium by different acid-modified biochar derived from corn straw: behavior and mechanism

2020 ◽  
Vol 81 (10) ◽  
pp. 2270-2280
Author(s):  
Yonggang Xu ◽  
Tianxia Bai ◽  
Yubo Yan ◽  
Yunfeng Zhao ◽  
Ling Yuan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrogen Ion ◽  
Corn Straw ◽  
Order Model ◽  
Freundlich Model ◽  
X Ray ◽  
Modified Biochar ◽  
Before And After ◽  
Pseudo Second Order ◽  
Kinetics Of

Abstract It is of great significance to remove Cr(VI) from water as a result of its high toxicity. Biochar from corn straw was modified by different acids (HNO3, H2SO4 and H3PO4) to remove Cr(VI) from aqueous solution. To estimate the removal mechanisms of Cr(VI) by the acid-modified biochars, batch experiments were performed in the light of contact time, Cr(VI) concentration, and pH, and the characteristics of acid-modified biochars before and after Cr(VI) adsorption were investigated by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of Cr(VI) by acid-modified biochars were consistent with the pseudo-second-order model, and the adsorption isotherm obeyed the Freundlich model. Furthermore, the acid- modified biochars could supply more oxygen-containing functional groups (-COOH and -OH) as electron donor (e−) and hydrogen ion (H+) to enhance the reduction of Cr(VI) to Cr(III), resulting in enhanced removal of Cr(VI). HNO3-modified biochar exhibited the highest removal efficiency of Cr(VI). In general, the acid modifition of biochar was an effective method to increase the removal of Cr(VI).

scholarly journals Orthophosphoric Acid Activated Babul Seed Carbon as an Adsorbent for the Removal of Methylene Blue

2008 ◽  
Vol 5 (4) ◽  
pp. 742-753 ◽  
Author(s):  
M. Sujatha ◽  
A. Geetha ◽  
P. Sivakumar ◽  
P. N. Palanisamy
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Orthophosphoric Acid ◽  
Chemical Activation ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Blue Dye ◽  
Equilibrium Data ◽  
Pseudo Second Order

An Experimental and theoretical study has been conducted on the adsorption of methylene blue dye using activated carbon prepared from babul seed by chemical activation with orthophosphoric acid. BET surface area of the activated carbon was determined as 1060 m2/g. Adsorption kinetics, equilibrium and thermodynamics were investigated as a function of initial dye concentration, temperature and pH. First order Lagergren, pseudo-second order and Elovich kinetic models were used to test the adsorption kinetics. Results were analyzed by the Langmuir, Freundlich and Temkin isotherm models. Based on regression coefficient, the equilibrium data found fitted well to the Langmuir equilibrium model than other models. The characteristics of the prepared activated carbon were found comparable to the commercial activated carbon. It is found that the babul seed activated carbon is very effective for the removal of colouring matter.

scholarly journals Fabrication of Amino Functionalized Magnetic Expanded Graphite Nanohybrids for Application in Removal of Ag(I) from Aqueous Solution

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Ying-Xia Ma ◽  
Yong-Xin Ruan ◽  
Dan Xing ◽  
Xue-Yan Du ◽  
Pei-Qing La
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Expanded Graphite ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
One Pot ◽  
X Ray ◽  
Pseudo Second Order

Ethylenediamine functionalized magnetic expanded graphite decorated with Fe3O4 nanoparticles (MEG-NH2) was fabricated by one-pot solvothermal method. The as-prepared MEG-NH2 nanohybrids were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Zeta potential analyzer. The effects of Fe3O4 content in MEG-NH2 nanohybrids, pH, initial concentration, contact time, and dosage on adsorption properties of the MEG-NH2 nanohybrids for Ag(I) from aqueous solution were investigated by batch experiments. The pseudo-first-order and the pseudo-second-order kinetic models were utilized to study adsorption kinetics. The experimental data was also analyzed with Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models. The results show that Ag(I) was reduced to silver in the process of the adsorption by MEG-NH2 nanohybrids; the experimental data was better fitted to pseudo-second-order model and Langmuir isotherm model which revealed that the adsorption process was a chemical adsorption by the formation of silver on the surface of MEG-NH2 nanohybrids.

scholarly journals Fly Ash Coated with Magnetic Materials: Improved Adsorbent for Cu (II) Removal from Wastewater

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Maria Harja ◽  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Dumitru Daniel Herea ◽  
...  
Keyword(s):  
Fly Ash ◽  
Adsorption Capacity ◽  
Copper Ions ◽  
Synthetic Wastewater ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Copper Adsorption ◽  
X Ray

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.

scholarly journals Biosorption and Diffusion Modeling of Pb(II) by Malt Bagasse

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Klaiani B. Fontana ◽  
Giane Gonçalves Lenzi ◽  
Erica R. L. R. Watanabe ◽  
Ervin Kaminski Lenzi ◽  
Juliana A. M. T. Pietrobelli ◽  
...  
Keyword(s):  
Sorption Process ◽  
Isotherm Models ◽  
Diffusion Modeling ◽  
Biosorption Capacity ◽  
Kinetic And Thermodynamic Parameters ◽  
Pseudo Second Order ◽  
Ph Optimization ◽  
Kinetics Of ◽  
And Diffusion

The removal of Pb(II) from water by biosorption processes onto malt bagasse was investigated and the kinetic and thermodynamic parameters were obtained; additionally a diffusion modeling was proposed. The characterization of malt bagasse was performed by FTIR and SEM/EDS. The experiments were conducted in batch system and an experimental design based response surface methodology was applied for agitation speed and pH optimization. The kinetics of biosorption followed pseudo-second-order model and the temperature of the process affected the biosorption capacity. Isotherm models of Langmuir, Freundlich, and Elovich were applied and the Langmuir model showed better fit and the estimated biosorption capacity was 29.1 mg g−1. The negative values obtained for ΔG° and positive values of ΔH° confirm, respectively, the spontaneous and endothermic nature of the process. The diffusion modeling was performed based on experiments in the absence of agitation to investigate the influence of the biosorbent on the sorption process of Pb(II) ions.

Efficient adsorption of chlorpyrifos onto modified activated carbon by gamma irradiation; a plausible adsorption mechanism

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky
Keyword(s):  
Gamma Irradiation ◽  
Area Measurement ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Pseudo First Order ◽  
Kinetics Of

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.

Study on the Formaldehyde Adsorption Kinetics of Dry Waters

2014 ◽  
Vol 809-810 ◽  
pp. 907-911
Author(s):  
Jun Long Wang ◽  
Jie Hou ◽  
Ting Jiang ◽  
Yong Jun He ◽  
Yao Dong Liang
Keyword(s):  
Adsorption Kinetics ◽  
High Speed ◽  
Adsorption Process ◽  
Average Diameter ◽  
Adsorption Rate ◽  
Absorption Kinetics ◽  
Order Model ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Formaldehyde Adsorption

Dry waters with an average diameter of 82 μm were prepared by a high speed mixed route. The formaldehyde absorption kinetics of dry waters was investigated by simulating indoor formaldehyde pollution in glass chamber. The results showed that pseudo-second order model could be used to simulate the adsorption process; the adsorption rate was highest in the initial 60 minutes; when the adsorption lasted for 180 minutes, the adsorption reached equilibrium.

scholarly journals Highly Efficient Adsorption of Aqueous Pb(II) with Mesoporous Metal-Organic Framework-5: An Equilibrium and Kinetic Study

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
José María Rivera ◽  
Susana Rincón ◽  
Cherif Ben Youssef ◽  
Alejandro Zepeda
Keyword(s):  
Kinetic Study ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Isotherm Models ◽  
Ionic Exchange ◽  
Order Kinetic ◽  
X Ray ◽  
Metal Organic ◽  
Mesoporous Metal ◽  
Organic Framework

Mesoporous metal-organic framework-5 (MOF-5), with the composition Zn4O(BDC)3, showed a high capacity for the adsorptive removal of Pb(II) from 100% aqueous media. After the adsorption process, changes in both morphology and composition were detected using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) system, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. The experimental evidence showed that Zn(II) liberation from MOF-5 structure was provoked by the water effect demonstrating that Pb(II) removal is not due to ionic exchange with Zn. A kinetic study showed that Pb(II) removal was carried out in 30 min with a behavior of pseudo-second-order kinetic model. The experimental data on Pb(II) adsorption were adequately fit by both the Langmuir and BET isotherm models with maximum adsorption capacities of 658.5 and 412.7 mg/g, respectively, at pH 5 and 45°C. The results of this work demonstrate that the use of MOF-5 has great potential for applications in environmental protection, especially regarding the removal of the lead present in industrial wastewaters and tap waters.

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