Biosorption of Pb(II) and Zn(II) by Extracellular Polymeric Substance (Eps) of Rhizobium Radiobacter: Equilibrium, Kinetics and Reuse Studies

Abstract

Abstract The extracellular polymeric substance (EPS) produced from Rhizobium radiobacter F2, designated as EPS F2 , was investigated as a biosorbent for the removal of Pb(II) and Zn(II) from aqueous solution. The optimum biosorption pH values were 5.0 for Pb(II) and 6.0 for Zn(II). Kinetics study revealed that the biosorption followed pseudo-first-order model well, and the equilibrium data fit the Langmuir model better. The adsorbed metal ions could be effectively desorbed by HCl. Desrobed EPSF2 regained 80% of the initial biosorption capacity after five cycles of biosorption-desorption-elution. These results demonstrated that EPS F2 could be a promising alternative for Pb(II) and Zn(II) removal from aqueous solution.