Adsorptive Removal of Cd2+ and Zn2 From Aqueous System by BSG

Abstract

The potential utilization of Brewer’s Spent Grain (BSG) was investigated in the removal of Cadmium and Zinc from aqueous system. Batch sorption process assessment of the effects of process variables showed that pH, initial metal ion concentration and dosage amount affect the sorption and uptake of Cd and Zn ions by BSG. Analysis of the sorption process using different kinetic models showed that the pseudo first order kinetic models gave poor descriptions of the process for Zn  was r² = 0.5268 but a good one for Cd at r² = 0.9618 while the pseudo second order kinetic model gave a good description of the process for both metal ions  (r²>0.98). The Pseudo second order rate constant obtained for Zn (1.0812mgg^-1min^-1) is than that for Cd (0.17mgg^-1min^-1).Equilibrium isotherm analysis of the sorption process data showed that the Langmuir isotherm gave a better description of the process than the Freundlich for Cd while both Freundlich and Langmuir fitted very well for Zn sorption by BSG. The results of the studies indicate that the metal ions were favourably adsorbed onto the adsorbent with a removal efficiency of 94.46% for Zn and 77.81% for Cd.

Keywords: Brewer’s Spent Grain, cadmium, zinc, sorption, Isotherm, Kinetics.