Ultrahigh and selective adsorption of Au(III) by rich sulfur and nitrogen-bearing cellulose microspheres and their applications in gold recovery from gold slag leaching solution

Abstract

• A novel adsorbent with high-density functional groups was prepared. • NS-CM exhibited ultrahigh capacity of 4656.9 mg/g in batch experiments. • The column adsorption capacity of NS-CM reached a significant breakthrough. • NS-CM can effectively recover trace Au(III) from gold slag leaching solution. • The adsorption mechanism was ion exchange, coordination and oxidation-reduction. In this work, we combined a powerful radiation grafting method that yields high-density functional groups containing rich sulfur and nitrogen with microcrystalline cellulose microspheres (MCCs) to achieve a novel functionalized cellulose microsphere (NS-CM) as a Au(III) adsorbent. It was found that high-density functional groups containing around 37.4 wt% sulfur and nitrogen in total on the NS-CM exhibited a maximum capacity of 4656.9 mg/g in batch experiments, which is the highest level recorded in comparison with other reported literatures. Meanwhile, the column adsorption capacity of NS-CM reached 3110 g/L in simulated acidic waste effluent, which is a significant breakthrough in Au(III) uptake. Finally, the NS-CM could selectively capture trace Au(III) from the actual gold slag leaching solution with an excellent adsorption efficiency of 95.17%. A well-designed adsorbent (NS-CM) with ultrahigh adsorption ability and excellent selectivity provided a very efficient, sustainable, and industrially feasible way for Au(III) to be recovered in leaching solution of gold slag, electronic waste, and other prospective sources.