Chromium (VI) Adsorption and its Kinetic Studies Using Industrial Spent Biomass

Biosorption is mass transfer phenomenon by which a substance can be transferred from liquid phase to the surface of a solid. The substance becomes bound, by physical and/or chemical interactions. Availability of large surface area, surface reactivity, high sorption capacity and low cost makes it feasible over other traditional methods of treatment. In this study important sorption parameters were investigated as a function of time, pH, initial chromium (VI) concentration, temperature and biomass dosage. Kinetics and equilibrium data were obtained from batch experiments. The biosorption kinetics were checked for both first order and second order models and it was found that the sorption process followed the pseudo-second order kinetics. Adsorption equilibria was checked for Langmuir, Freundlich, Redlich-Peterson and Tempkin models and the process was well described by Freundlich isotherm (R²=0.9992), Redlich-Petersen isotherm (R²=0.961) and Tempkin Isotherm (R²=0.9592) models as compared to Langmuir Isotherm (R²=0.5702) model. The maximum adsorption capacity of the biomass was 14.2 mg/g at a temperature of 298K and pH of 2.0. The scanning electron micrograph revealed the surface texture and morphology of multilayer adsorption. Surface and pore size analysis through BET revealed that industrial spent has a specific surface area of 4.8477 m²/g and pore diameter 56.865oA. The present work reveals that spent biomass can be effectively used for Chromium (VI) removal at low concentrations.