Lignin-polyethylene composite adsorbents for gold capture

We report in this paper the synthesis of lignin-polyethylene composite pellet adsorbents and their adsorption performances toward the capturing of Au(III) species from aqueous solutions. In this adsorbent design, lignin (L) as an abundantly available and low-cost biopolymer is used as the active adsorbing material, while polyethylene (PE) serves as the inert binder maintaining the structural/mechanical integrity of the adsorbents. Systematic characterizations have been undertaken on the composite adsorbents to determine their performances, including the effect of pellet composition, adsorbent dosage, pH, and co-existing ions on the adsorption, as well as the adsorption kinetics, isotherm, and reusability. The highly selective gold capture in the presence of co-existing ions has also been demonstrated with the composite adsorbent L40-PE60. This work shows the strong potential of the lignin-polyethylene composite adsorbents for the low cost and easy processing of industrial gold capturing in gold mining processes. • Lignin-polyethylene composites were developed for efficient Au(III) capture in gold mining. • L40-PE60 composite excelled with high selectivity and rapid gold adsorption. • pH sensitivity was observed with optimal performance under acidic conditions. • Potential for eco-friendly, cost-effective gold recovery in industrial processes.