Study of chemistry of CR(VI)/Cr(III) biosorption from batch solutions and electroplating industrial effluent using cyanobacteria spirulina platensis

Abstract

The biosorption of Cr(III)-Cr(VI) from aqueous solutions on dry Spirulina platensis biomass was tested under laboratory conditions as a function of pH, initial metal ion concentration, biomass dosage, time and temperature. Optimum adsorption pH values of Cr(III) and Cr(VI) were determined as 3.0 and 2.0, respectively. The Langmuir adsorption isotherm model fit well the sorption equilibrium of the experimental data obtained for Cr(III), while Freundlich isotherm fit better data obtained for Cr(VI). The kinetic data were best described using the pseudo second-order kinetic model (R2> 0.99). The adsorption process was exothermic and the values of thermodynamic parameters of the process were calculated. Spirulina platensis biomass was also used as a biosorbent for the removal of Cr(VI) from electroplating industry effluent as a function of biosorbent dosage and contact time.