Characterization of Acidosasa edulis shoot shell and its biosorption of copper ions from aqueous solution

The Acidosasa edulis shoot shell (AESS) was used to remove Cu2+ from water for the first time. The biosorbent was characterized by acid–base titration, point zero charge determination, SEM, XRD and FTIR. The effects of operation parameters were studied. Kinetics data were best described by pseudo-second-order model. The equilibrium data of biosorption were best described by Langmuir isotherm model. The calculated thermodynamic parameters indicated that the biosorption was endothermic and spontaneous. Mechanism analysis indicated that biosorption of Cu2+ mainly occurred in the amorphous region of AESS. Phenolic sites and carboxyl sites in the amorphous region of AESS were mainly responsible for the biosorption. Phenolic sites formed complex with Cu2+, while carboxyl sites exchanged H+ with Cu2+ by ion-exchange mechanism. The results revealed that AESS could be used as an effective and low-cost biosorbent for Cu2+ removal from aqueous solutions.