Synchronous catalysis of sulfite oxidation and abatement of Hg2+ in wet desulfurization using one-pot synthesized Co-TUD-1/S

Cobalt-based catalysts can promote sulfite oxidation to recover the valuable byproducts formed during wet magnesia desulfurization. However, Hg(II) in the desulfurization slurry degrades the quality of reclaimed products and poses considerable environmental risk. Here, a bifunctional sulfur-doped catalyst/adsorbent, Co-TUD-1/S, is prepared through one-pot synthesis, in which the sulfur site is designed for trapping aqueous Hg 2+ . The catalytic rate of Co-TUD-1/S for MgSO 3 is 0.083 mmol/L/S, which is 10.4 times of that under non-catalytic condition, the removal efficiency of Hg 2+ is higher than 90%. The isothermal models and kinetic models for the adsorption of Hg 2+ are well-fitted to the Langmuir model and pseudo-second-order model, respectively, and the maximum adsorption capacity of experimental data is 96 mg/g. The characterization results confirm that Co 3 O 4 is functioned as the active catalysis site, and the formation of S–Hg bonds plays a crucial role in Hg 2+ capture. Density functional theory calculations reveal that the Co site is more likely to combine with sulfite rather than Hg 2+ , which reduces the interference of absorbed Hg 2+ on the catalytic activity of Co. Specialization and cooperation between the catalysis site of –Co and adsorption site of –S are realized. The results reveal that the use of Co-TUD-1/S is a feasible strategy for improving wet desulfurization efficiency.