Detoxification of copper bearing effluents using low cost biosorbent maize bran

Abstract

Maize bran a low cost biosorbent has been used for the removal of Cu (II) from wastewater. The effect of various parameters, such as contact time, adsorbate concentration, pH of the medium and temperature have been studied. The conditions for the optimum removal of Cu (II) (90.0%) were found at pH of 6.5, initial Cu (II) concentration, 40.0 mg/L and temperature 20°C. Dynamics of the sorption process were studied and the values of rate constant of adsorption, rate constant of intraparticle diffusion and the mass transfer coefficient were calculated. Mass transfer of Cu (II) from the bulk to the solid phase, namely maize bran has also been studied at different temperatures. Different thermodynamic parameters, such as ΔG°, ΔH° and ΔS° have also been evaluated and it has been found that the reaction was spontaneous and exothermic in nature. The applicability of Langmuir isotherm suggests the formation of monolayer coverage of adsorbate on the surface of the adsorbent. A generalised empirical model is proposed for the kinetics at different initial concentration. © 2004 - Kalpana Corporation.