Mo3S132− Intercalated Layered Double Hydroxide: Highly Selective Removal of Heavy Metals and Simultaneous Reduction of Ag+ Ions to Metallic Ag0 Ribbons

Abstract We demonstrate a new material by intercalating Mo 3 S 13 2− into Mg/Al layered double hydroxide ( abbr . Mo 3 S 13 ‐LDH), exhibiting excellent capture capability for toxic Hg 2+ and noble metal silver (Ag). The as‐prepared Mo 3 S 13 ‐LDH displays ultra‐high selectivity of Ag + , Hg 2+ and Cu 2+ in the presence of various competitive ions, with the order of Ag + >Hg 2+ >Cu 2+ >Pb 2+ ≥Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ . For Ag + and Hg 2+ , extremely fast adsorption rates (≈90 % within 10 min, >99 % in 1 h) are observed. Much high selectivity is present for Ag + and Cu 2+ , especially for trace amounts of Ag + (≈1 ppm), achieving a large separation factor (SF Ag/Cu ) of ≈8000 at the large Cu/Ag ratio of 520. The overwhelming adsorption capacities for Ag + ( q m Ag =1073 mg g −1 ) and Hg 2+ ( q m Hg =594 mg g −1 ) place the Mo 3 S 13 ‐LDH at the top of performing sorbent materials. Most importantly, Mo 3 S 13 ‐LDH captures Ag + via two paths: a) formation of Ag 2 S due to Ag‐S complexation and precipitation, and b) reduction of Ag + to metallic silver (Ag 0 ). The Mo 3 S 13 ‐LDH is a promising material to extract low‐grade silver from copper‐rich minerals and trap highly toxic Hg 2+ from polluted water.