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

Water Pollution Research Laboratory, Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi-221 005, India E-mail : hasanitbhu@yahoo.co.in Manuscript received I 11 July 2003, revised 11 May 2004, accepted 22 July 2004 A novel biosorbent maize bran has been successfully utilised for the removal of cadmium(ll) from wastewater. The maximum removal of cadmium(ll) bus 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 hove been Investigated. Dynamics of the sorption process were studied and the values of rate constant of adsorption, rote constant of interparticle diffusion and moss transfer coefficient were calculated. Various thermodynamic parameters such as ΔGº , ΔHº and ΔSº 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