Isotherms and Kinetics Studies of Biosorption Nickel (Ii) and Chromium (Vi) From Aqueous Solution by Dried Activated Sludge Publisher



Malakootian M¹ ; Ghadiri SK² ; Yousefi N² ; Fatehizadeh A³
Source: International Journal of Environmental Health Engineering Published:2012

Abstract

Aims: The aim of this study is the recovery of municipal refuse and using it as a biosorbent for Nickel (II) and Chromium (VI) (Ni2+and Cr6+)removal from aqueous solutions. Materials and Methods: Activated sludge was obtained from the wastewater treatment plant in a dairy industry. All experiments were performed in the batch system and effective parameters such as the pH, adsorbent dosage, and the initial concentration and contact time of Ni2+and Cr6+were investigated. The adsorption isotherms and kinetics were evaluated to describe the metal uptake and dynamic reactions. Results: The results of this study showed that with an increasing adsorbent dose and contact time, Ni2+and Cr6+removal efficiency increased. The maximum adsorption of Ni2+and Cr6+was obtained in pH 6 and 2, respectively. Meanwhile, with increasing Ni2+and Cr6+concentration, the removal efficiency decreased. The results best fitted the Langmuir isotherm and the maximum absorption capacity of Ni2+and Cr6+onto dry activated sludge (DAS) were 2.17 and 2.23 mg/g, respectively. Analysis of the adsorption kinetics showed that the intraparticle diffusion kinetic had been good and presented Ni2+and Cr6+uptake onto DAS, and the intraparticle diffusion rate constant of Ni2+and Cr6+ were 0.044 and 0.042 (mg/g min0.5), respectively. Conclusions: According to the results, dry activated sludge is suggested as a low cost and available adsorbent for removing Ni2+and Cr6+from aqueous solutions. © 2012 Medknow. All Rights Reserved.