Biosorption of copper by calcium alginate from excess activated sludge

To evaluate the potential use of the bacterial alginate extracted from excess activated sludge as a sustainable copper bioadsorbent, dried alginate-Ca made from municipal excess activated sludge was characterized by atomic force microscopy, and tested in a batch system. The alginate-Ca yield from the activated sludge was 103 +/- 15 mg g(-1). The maximum Cu2+ uptake was 41.96 mg g(-1). Accumulation of Cu2+ reached equilibrium within 50 min and followed the Langmuir adsorption isotherm. The solution pH and initial Cu2+ concentration were critical for Cu2+ biosorption. The sludge alginate-Ca bioadsorbent could be regenerated by 100 mmol L(-1) HCl with 82% Cu2+ recovery. Calcium alginate from excess activated sludge was proved to be a good bioadsorbent for heavy metal elimination.