Removal of hazardous hexavalent chromium from aqueous solution using divinylbenzene copolymer resin

This paper presents the removal of hazardous hexavalent chromium from liquid waste streams using divinylbenzene copolymer resin Amberlite IRA 96. Important sorption parameters such as contact time, pH, resin dosage and initial metal concentration were studied at 30 degrees C. The kinetic study was conducted using pseudo-first and pseudo-second-order kinetics at 30 degrees C. The sorption process was found to be pH dependent. Maximum removal was obtained at pH 2 under optimized conditions. The sorption process was rapid and 99 % of the removal was achieved in first 30 min. The equilibrium data were fitted to both Langmuir and Freundlich models. The better regression coefficient (R-2) in Freundlich model suggests the multilayer sorption process. The value of Gibbs free energy for sorption process was found to be -12.394 kJmol(-1). The negative value indicated the spontaneity of the sorption process. Scanning electron microscope and energy dispersive X-ray spectroscopy studies were conducted to find the role of surface morphology during sorption process. The Fourier transform infrared study was conducted to identify the functional groups responsible for interaction between the resin and chromium. Desorption and regeneration studies were also carried out.