Facile preparation of L-cysteine–modified cellulose microspheres as a low-cost adsorbent for selective and efficient adsorption of Au(III) from the aqueous solution

A facile method to synthesize adsorbent based on cellulose modified by amino acid was developed. The novel L-cysteine–functionalized adsorbent for Au(III) recovery was synthesized via radiation grafting technique. Glycidyl methacrylate (GMA) was grafted on the surface of microcrystalline cellulose microsphere (MCC); next, ring-opening reaction was performed to immobilize L-cysteine. The adsorption abilities of the adsorbent (CysR) were tested. Batch experiments suggested that the maximum adsorption capacity of Au(III) is 714.28 mg/g calculated by Langmuir model. The adsorption kinetic data was followed by pseudo-second-order model. CysR showed excellent selectivity for Au(III) even the concentration of competing ions was all ten times than that of Au(III). The column experiments revealed that Au(III) could be efficiently adsorbed by CysR competition with equal amounts of Ni(II) and Zn(II). Moreover, XPS analysis demonstrated that the adsorbed Au(III) was reduced to Au(I) and Au(0). The adsorption performance certified that CysR was a promising adsorbent for Au(III) recovery.