Lowcost bio-sorbent 'maize bran' for the removal of cadmium from wastewater

Abstract

A novel biosorbent maize bran has been successfully utilised for the removal of cadmium(II) from wastewater. The maximum removal of cadmium(II) has been found to be 94.5% at pH 8.6, initial CdII concentration 1.25 mg L-1 and temperature 20°C. The effect of different parameters such as contact time, adsorbate concentration, pH of the medium and temperature have been investigated. Dynamics of the sorption process were studied and the values of rate constant of adsorption, rate constant of intraparticle diffusion and mass transfer coefficient were calculated. Various thermodynamic parameters such as ΔG°, ΔH° and ΔS° have also been evaluated and critically discussed. It has been concluded that the reaction was spontaneous and exothermic in nature. The applicability of Langmuir isotherm suggests the formation of monolayer coverage of the adsorbate on the surface of adsorbents.