Selective removal of Au(III) from wastewater by pyridine-modified chitosan.

A pyridine-modified chitosan (PMCS) adsorbent with excellent adsorption performance and specific selectivity for Au(III) in wastewater was prepared. FTIR, SEM, XPS and XRD were used to study its adsorption performance, and various models were used to fit and analyze the experimental adsorption data. The maximum adsorption capacity of PMCS for Au(III) is 549.41 mg/g (298 K, pH = 4). The data analysis results prove that the PSO and Langmuir models best describe the adsorption process. Adsorption experiments in the presence of multiple ions proved that PMCS is selective for the adsorption of Au(III). The adsorption and desorption experiments showed that the adsorption rate of PMCS could still reach 94.77% after three cycles. In summary, PMCS was demonstrated to be a high-quality material for the adsorption of Au(III) from wastewater due to its excellent adsorption performance, specific selectivity and reusability.