Biosorption of Cu²⁺, Pb²⁺ and Cr⁶⁺ by a novel exopolysaccharide from Arthrobacter ps-5

The biosorption behaviors and mechanisms for Cu²⁺, Pb ²⁺ and Cr⁶⁺ by a novel exopolysaccharide (EPS) from Arthrobacter ps-5 have been studied in the paper. The influences of EPS concentration, solution pH and ionic strength on adsorption property were investigated. The EPS showed strong biosorption capability, up to 169.15 mg/g of Cu²⁺, 216.09 mg/g of Pb²⁺ and 84.47 mg/g of Cr ⁶⁺, respectively. With the additional concentration of Ca ²⁺ and K⁺ increased, the biosorption ability on Cu ²⁺, Pb²⁺ and Cr⁶⁺ decreased significantly and followed the order of K⁺ < Ca²⁺. Infrared spectrometry analysis demonstrated that the groups of O-H, C=O, C-O-C and C=O-C of the EPS involved in metal biosorption process were the main functional groups for binding metal ions.