Achieving Large-Capability Adsorption of Hg(0) in Wet Scrubbing by Defect-Rich Colloidal Copper Sulfides under High-SO(2) Atmosphere

This paper reports on a novel method to remove Hg(0) in the wet scrubbing process using defect-rich colloidal copper sulfides for reducing mercury emissions from non-ferrous smelting flue gas. Unexpectedly, it migrated the negative effect of SO(2) on mercury removal performance, while also enhancing Hg(0) adsorption. Colloidal copper sulfides demonstrated the superior Hg(0) adsorption rate of 306.9 μg·g(−1)·min(−1) under 6% SO(2) + 6% O(2) atmosphere with a removal efficiency of 99.1%, and the highest-ever Hg(0) adsorption capacity of 736.5 mg·g(−1), which was 277% higher than all other reported metal sulfides. The Cu and S sites transformation results reveal that SO(2) could transform the tri-coordinate S sites into S(2)(2−) on copper sulfides surfaces, while O(2) regenerated Cu(2+) via the oxidation of Cu(+). The S(2)(2−) and Cu(2+) sites enhanced Hg(0) oxidation, and the Hg(2+) could strongly bind with tri-coordinate S sites. This study provides an effective strategy to achieve large-capability adsorption of Hg(0) from non-ferrous smelting flue gas.