Production of H₂S with a Novel Short-Process for the Removal of Heavy Metals in Acidic Effluents from Smelting Flue-Gas Scrubbing Systems

Abstract

Direct sulfidation using a high concentration of H2S (HC-H2S) has shown potential for heavy metals removal in various acidic effluents. However, the lack of a smooth method for producing HC-H2S is a critical challenge. Herein, a novel short-process hydrolysis method was developed for the on-site production of HC-H2S. Near-perfect 100% efficiency and selectivity were obtained via CS2 hydrolysis over the ZrO2-based catalyst. Meanwhile, no apparent residual sulfur/sulfate poisoning was detected, which guaranteed long-term operation. The coexistence of CO2 in the products had a negligible effect on the complete hydrolysis of CS2. H2S production followed a sequential hydrolysis pathway, with the reactions for CS2 adsorption and dissociation being the rate-determining steps. The energy balance indicated that HC-H2S production was a mildly exothermic reaction, and the heat energy could be maintained at self-balance with approximately 80% heat recovery. The batch sulfidation efficiencies for As­(III), Hg­(II), Pb­(II), and Cd­(II) removal were over 99.9%, following the solubilities (K sp) of the corresponding metal sulfides. CO2 in the mixed gas produced by CS2 hydrolysis did not affect heavy metals sulfidation due to the presence of abundant H+. Finally, a pilot-scale experiment successfully demonstrated the practical effects. Therefore, this novel on-site HC-H2S production method adequately achieved heavy metals removal requirements in acidic effluents.

Self-assembling fluorescent hydrogel for highly efficient water purification and photothermal conversion

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Boosting the growth and aggregation of sulfide nanoparticlesviaregulating heterogeneous nucleation for enhanced sedimentation

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Mechanism Study of Organic Sulfur Hydrogenation over Pt- and Pd-Loaded Alumina-Based Catalysts

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