Study of biosorption of copper and silver by marine bacterial exopolysaccharides

Abstract

Metal bioremediation was studied by biosorption of analytical grade copper Cu(II) and silver Ag(I) by an exopolysaccharide (EPS) produced by marine bacteria from French Polynesia. Colorimetric analysis showed that EPS was composed of neutral sugars, uronic acids, acetate and especially high sulfate amount (29%). Metal biosorption experiments were conducted in batch process. Results showed that the maximum sorption capacities calculated according to Langmuir model were 400 mg g-1 EPS (6.29 mmol g-1) and 256 mg g -1 EPS (2.38 mmol g -1 ) for Cu(II) and Ag(I), respectively. The influence of pH, biosorbent concentration, ionic strength on EPS biosorption capacities was investigated.