Adsorption and reduction behavior and mechanism of Au(III) on reductive cellulose-based aerogel

Abstract

A reductive cellulose-based aerogel (VTCA) was fabricated from cellulose by introducing valonea tannin through cross-linking reaction. VTCA owned high porosity of more than 96% with the average pore size of 30–50 µm, and it exhibited good adsorption performance for Au(III) at a wide pH values range (1−8) with the max adsorption capacity of 243.1 mg g−1. VTCA showed good adsorption performance for Au(III) under the interference of various co-existing ions. The adsorption obeyed the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, and temperature rise was favorable for adsorption. The adsorption-reduction mechanisms mainly involved electrostatic interaction, chelation adsorption and reduction. Au(III) could be effectively adsorbed onto the surface of VTCA by electrostatic attraction and chelation, and then reduced in situ to Au0 by phenolic hydroxyl on tannic structure. This study provides a new adsorbent with the advantages of convenient preparation and high efficiency, and it has great application prospects in the enrichment and recovery of precious metals in waste liquid and the treatment of oxidized pollutants.