Biosorption of Copper (II) from Aqueous Solutions with Rape Straw

Abstract

Adsorption of Cu²⁺ by rape straw under acidic conditions was investigated in this paper. Influences of pH (2.2–6.2), rape straw concentration (5.0–15.0 g total solid (TS)/L), and initial Cu²⁺ concentration (40.0–200.0 mg/L) on the adsorption of Cu²⁺ by rape straw were evaluated. The maximum adsorption capacity of Cu²⁺ could reach 7.3 mg/g with a removal efficiency of 90% under the optimal conditions of 64.0 mg/L Cu²⁺, 7.5 g TS/L of rape straw and pH 5.0. Results indicated that both Langmuir and Freundlich adsorption models were able to adequately describe the biosorption equilibrium of Cu²⁺ onto rape straw. Kinetics analysis results showed that the process followed the pseudo–second-order adsorption kinetics.

Keywords:

• acid mine drainage
• adsorption
• isotherm equation
• kinetics
• rape straw

Acknowledgments

The authors wish to thank the NSFC (40902019 and 40872047) and National Key Basic Research Program of China (2007CB815603).