Adsorption behavior of copper ions using crown ether-modified konjac glucomannan

A novel supramolecular polysaccharide composite [KGM + DB18C6] was prepared from konjac glucomannan (KGM) and dibenzo-18-crown-6 (DB18C6) using ceric ammonium nitrate as initiator. The products were characterized by FTIR, TG, DSC, UV–Vis, XRD, solid-state 13C NMR, and SEM. Due to the introduction of crown ether, [KGM + DB18C6] showed good adsorption performance for Cu2+ in aqueous, and the maximum adsorption capacity was 194 mg/g under the optimal adsorption condition. The adsorption kinetics of [KGM + DB18C6] on Cu2+ could be described by the pseudo-second-order kinetic model. The adsorption isotherms of [KGM + DB18C6] on Cu2+ followed the dual-site Langmuir-Freundlich model. In addition, high recoveries of Cu2+ (from 82.65 to 88.47%), and low relative standard deviation (below 5.00%) were obtained by applying the product in real samples, indicating that [KGM + DB18C6] was a good absorbent for removing Cu2+ in wastewater.