期刊
ENVIRONMENTAL SCIENCE & TECHNOLOGY
卷 55, 期 6, 页码 3988-3995出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.est.0c07884
关键词
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资金
- National Key R&D Program of China [2017YFC0210500]
- National Natural Science Foundation of China [21806105, U1662132]
A novel short-process hydrolysis method was developed for on-site production of HC-H2S, achieving near-perfect efficiency and selectivity for heavy metals removal in acidic effluents. The process showed no apparent residual poisoning, with CO2 having a negligible effect on CS2 hydrolysis. Pilot-scale experiments successfully demonstrated the practical effects of this method for heavy metal removal.
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 (Ksp) 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.
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