Ultrahigh efficient and selective adsorption of Au(III) from water by novel Chitosan-coated MoS2 biosorbents: Performance and mechanisms

[Display omitted] •Different mass ratios chitosan/MoS2 biosorbents used for the first time to recover gold ions from solution.•CS-MoS2 complex exhibited ultrahigh sorption capacity up to 3108.79 mg/g only in 300 min.•The three biosorbents possess superior selectivity and reusability.•Adsorption mechanism of CS-MoS2-1, 2, 3 for Au(III) is electrostatic attraction and complexation. The design and synthesis of high-performance materials for the recovery of gold are of paramount importance to alleviate its high consumption and protect the environment. Herein, three different ratios biosorbents (CS-MoS2-1, 2, 3) were successfully synthesized by embeding MoS2 into the crosslinking chitosan to recover gold ions from solution. These materials not only inherit the excellent properties of chitosan, but also possess the sulfur-rich surface of MoS2, making that the maximum adsorption capacity of CS-MoS2-1, 2 and 3 were 2012.46, 2611.32 and 3108.79 mg/g, respectively. Besides, these biosorbents show outstanding selectivity for gold ions in the presence of coexisting ions, and demonstrate attractive reusability after four cycles. Adsorption mechanism of the three biosorbents to Au(III) was mainly electrostatic attraction and coordination. With the easy synthesis, environmental-friendly and ultra-efficient performance, CS-MoS2-1, 2, 3 are expected to be a promising candidate for Au(III) adsorption from aqueous media.