Papers by Keyword: Cu(II)

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Authors: De Ling Chi, Kai Zhao, Fei Fei Zhang, Zong Hua Wang
Abstract: An electrochemical sensor for the detection of Cu (II) ion is described by using poly (vinyl alcohol) (PVA) and carboxylic multi-walled carbon nanotubes (c-MWNT) modified glassy carbon electrode (GCE) by anodic stripping voltammetry (ASV). PVA/c-MWNT film greatly improves the sensitivity of determining Cu (II). The striping peak currents change linearly with the concentration of Cu (II) from 1.0×10-8 to 8.0×10-5 mol/L for an accumulation time of 200 s, correlation coefficient r = 0.9980. The detection limit is as low as 5.0×10-9 mol/L. The high sensitivity, selectivity, and stability of the PVA/c-MWNT film demonstrated its practical application.
Authors: Jun Ren, Ya Qiong Zhao, Dong Dong Gou, Ling Tao, Mei Wei Zhang
Abstract: Adsorption of Cu(Ⅱ) onto natural attapulgite was investigated with respect to temperature, initial concentration and contact time. The adsorption process can be well described by the pseudo-second-order kinetic model, and the equilibrium adsorption isotherm was closely fitted with the Freundlich model. Enthalpy change(△H0), entropy change(△S0) and Gibbs free energy change(△G0) were calculated from the temperature dependent sorption data, and the results indicated that the sorption of Cu(Ⅱ) on attapulgite was a spontaneous process, and the sorption was endothermic.
Authors: Yan Yu, Feng Yuan Huang
Abstract: In the present paper, the ability of carboxymethylcellulose sulfate (CMC-S) for Cu(II) removal was studied. The influence of factors, such as the pH value, the initial copper concentrations, and the contact time, were investigated in detail. Atomic absorption spectrophotometer was applied to determined the concentration of Cu(II). The results showed that the adsorption process was strongly dependent on the pH value and the initial copper concentration. The optimum pH value was in the range of 6-7. The theoretical adsorption capacities for Cu(II) was 127.7 mg/g. The equilibrium data was well fitted to the Langmuir isotherm model at 25°C, which can be explained as a monolayer adsorption.
Authors: Li Li Yu, Lin Yao
Abstract: In this study, we describe a novel adsorbent, thiourea impregnated gelatin microspheres(TIGM) which were synthesized from thiourea impregnated gelatin by inverse suspension polymerization with glutaraldehyde as crosslinker. With the aim to investigate the absorption kinetics of Cu(II) on TIGM, the absorption equilibrium, the effects of temperature on the absorption was fully discussed. It was found that this adsorbent is effective for the removal of Cu(II) from aqueous solutions. Results of the experiments presented that the thiourea was uniformly dispersed in microspheres mainly through chemical bonds, and the adsorption isotherms of Cu(II) on TIGM fits well both with the classical Freundlich equation and the Langmuir equation. It was also suggested that the adsorption rate of Cu (II) was faster at higher temperature, and the amount of the adsorption also increases with the increasing of temperature. According to the research, the maximal adsorption capacity is obtained when pH is 5 to 9, and the adsorption kinetics of Cu(II) onto TIGM could be described by pseudo-first-order rate mode.
Authors: Zheng Jun Gong, Cong Cong Tang, Cai Yun Sun, Lu Tang, Jun Chen
Abstract: A natural peanut shell was used as adsorbent for removal of Cu(Ⅱ) from aqueous solution. Optimum conditions for the elimination of Cu(Ⅱ) from aqueous solution were established by means of a batch adsorption technique. The applicability of the Langmuir and Freundlich adsorption isotherms for the present system was tested. The Langmuir adsorption capacity Qmax (mg/g) is 39.68 and the equilibrium constant b is 0.00776. The Freundlich adsorption capacity k is 0.978 and adsorption intensity n is 1.65. The goodness of fitness was obtained with the Langmuir and Freundlich adsorption isotherms from the equilibrium adsorption data.
Authors: Chun Mei Niu, Shao Ying Li, Dong Huang
Abstract: Crosslinked Carboxymethyl Konjac Glucomannan(CMKGM) with substitution degrees ofcarboxymethyl group(DS)0.265, 0.457 and 0.586 were prepared through reaction of monochloroacetic acid, konjac glucomannan(KGM) and epichlorohydrin and used to adsorb Cu(II) from the aqueous solutions of copper nitrate. The effects of pH, adsorbent dose, initial concentration of Cu(II), adsorption time and temperature on adsorption capacity were investigated. The results showed that adsorption capacity increased with an increasing DS of the carboxymethyl groups. Equilibrium adsorption time was 20 min or so and was independent on DS. The adsorption followed Langmuir isotherm equation. Ligand ion adsorption between carboxymethyl group and Cu(II) was thought to be predominate in the process of adsorption according to the relationship between DS and thermodynamic parameters. CMKGM can be used as cheaper and more effective adsorbents.
Authors: Noorul Farhana Md Ariff, Megat Ahmad Kamal Megat Hanafiah, Wan Saime Wan Ngah
Abstract: In this study, cross-linked chitosan coated bentonite (CCB) beads were prepared as a potential adsorbent to adsorb Cu(II) from aqueous solution. As adsorption capacity was affected by several conditions such as initial Cu(II) concentrations, stirring period and temperature, these parameters were important to be investigated. Three different concentrations of Cu(II) were used in the kinetic study, which were 10, 25 and 50 mg/L. The experimental data was found fitted well with the pseudo-second-order model, an indication that chemisorption was the rate controlling mechanism. Isotherm study was done at different temperatures with concentration of Cu(II) was varied from 10 to 200 mg/L. The maximum monolayer adsorption of Cu(II) on CCB beads based on Langmuir isotherm model at 300, 310 and 320 K were 114.94, 119.05 and 77.52 mg/g, respectively. Therefore, adsorption of Cu(II) was preferred at lower temperatures. This work proved CCB beads as an effective adsorbent for fast removal of Cu(II) from wastewater solutions.
Authors: Hong Mei Deng, Yong Heng Cheng, Xiang Yang Chang, Jian Gong, Cui Qin Wu, Tao Liu
Abstract: Cedar sawdust (Cedrus deodara), an agricultural by-product abundant in China, was used as an adsorbent for the removal of Cu(II) from aqueous solutions. The extent of adsorption was investigated as a function of pH, contact time, adsorbate concentration and reaction temperature. The Cu(II) removal was pH-dependent, reaching a maximum at pH 5. The adsorption process followed pseudo-second-order kinetics and equilibrium was reached at 60 min. The rate constantly increased with the increase of temperature, indicating the endothermic nature of adsorption. The equilibrium adsorption capacity of Cu(II) determined from the Langmuir equation was 64.52 mg/g at 25°C. The equilibrium data fitted very well to the Freundlich isotherm model as compared to the Langmuir isotherm. The negative ΔGo values at various temperatures confirm that the adsorption processes are spontaneous. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) analysis of cedar sawdust, before and after adsorption of Cu(II), suggested that the main mechanisms involved in the removal of Cu(II) might be the ionic exchange and complexation.
Authors: Ling Xian Luo, Tai Zhi Zhang, Lv Bao Tong
Abstract: The objective of this study is to assess the potential applicability of an extracellular biopolymer (PA-2) produced by Pseudomonas alcaligenes as biosorbent remove the Cu(II) ions from environmental and industrial wastewater. The effects such as pH, Cu(II) initial concentration and sorbate-sorbent contact time and agitating speed on the adsorption capacities of PA-2 were studied. Biosorption equilibriums were rapidly established in about 60 min and the adsorption kinetics followed the pseudo-second order kinetic model. Biosorption equilibrium datas were better described by Langmuir isotherm model. The maximum Cu(II) adsorption capacity determined from Langmuir isotherm were 81.36 mg /g PA-2. The carboxyl and hydroxyl groups of the PA-2 were involved in chemical interaction with the Cu(II) ions depicted by Fourier transform infrared spectroscopic (FTIR) results. The present study indicated that PA-2 may be used as an inexpensive, effective and easily cultivable biosorbent for the removal of Cu(II) ions from environmental and industrial wastewater.
Authors: Yan Li Mao, Rui Qun Liu, Shi Tian Luo, Peng Xiang Xu, Le Du, Kui Zhang
Abstract: In the present study we reported the feasibility of extracellular biopolymer(PF01) produced by Pseudomonas fluorescence as an alternative biosorbent to remove Cu(II) ions from environmental wastewater. The ability of PF01 to remove the Cu(II) ions was investigated by using batch biosorption procedure. The effects such as pH, dosage of biosorbent, Cu(II) initial concentration and sorbate–sorbent contact time on the adsorption were studied. The pseudo-second order kinetics and Langmuir isotherm models were noted be fit to the experimental data. The maximum Cu(II) adsorption capacity was 78.99 mg/g at pH 5.0 , at 28°C. The carboxyl , hydroxyl and amino groups of the PF01 were involved in chemical interaction with the Cu(II) ions depicted by Fourier transform infrared spectroscopic (FTIR). The study points to the potential of new use of extracellular biopolymer PF01 as an effective biosorbent for the removal of Cu(II) from environmental wastewater.
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