Selective Adsorption of AuIII from Aqueous Solution Using 2,5‑Dimercapto‑1,3,4‑thiadiazole Modified Persimmon Tannin

Abstract

A one-pot synthesized persimmon tannin (PT)-based novel biosorbent modified with 2,5-dimercapto-1,3,4-thiadiazole (DMTD) was prepared for the selective adsorption of Au III from aqueous mixtures. The synthesized biosorbent was designated as DMTD-PT and characterized using elemental analysis, zeta potential, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The batch adsorption experiments in a model electronic waste leachate revealed that both DMTD-PT and PT had poor affinity for coexisting base metal ions, however, DMTD-PT and PT adsorbed 97.7 and 32.7%, respectively, of Au III with an initial Au .A kinetic study in combination with XPS and FTIR analyses of fresh and spent DMTD-PT further revealed that the potential biosorption mechanism can be attributed to the collaboration of electrostatic interactions and coordination.