ENVIRONMENTAL EFFECTIVENESS OF RECOVERING AU(III) IONS FROM INDUSTRIAL WASTEWATER USING FUNCTIONAL SORBENTS

This study compared the sorption properties of the functional sorbents NT-EXG, KrK-EXG, and KrTK-EXG for treating aqueous and process solutions containing Au(III) ions and recovering gold as a secondary resource. The study evaluated maximum and dynamic sorption capacities, the effect of pH, and sorbent stability over repeated adsorption–desorption cycles. KrTK-EXG exhibited maximum and dynamic sorption capacities of 148.5 and 66.8 mg/g, respectively, and performed well at pH 6.0–6.5. It retained 94.2% of its initial sorption activity after five adsorption–desorption cycles. Operation at near-neutral pH can reduce the use of strong acids, the risk of corrosion, and the generation of secondary waste. Au(III) uptake is attributed to coordination and electrostatic interactions with oxygen-, nitrogen-, and sulfur-containing functional groups in the sorbent. The results indicate that KrTK-EXG is a promising sorbent for treating gold-bearing industrial wastewater and process solutions, recovering gold, and reducing the anthropogenic metal load on water resources.