Electrochemically enhanced liquid-phase catalysis for simultaneous purification of phosphine, hydrogen sulfide and hydrogen cyanide: Interactions and synergistic mechanisms

Abstract

The growth of modern industry has resulted in the unregulated release of an increasing number of industrial tail gases (especially toxic and hazardous gases), putting significant strain on the environment and human health. In this paper, a simple and effective electrochemically enhanced liquid-phase catalysis approach was proposed for simultaneous removal of PH3, H2S, and HCN from industrial tail gases. Pd(II) and Cu(II) were used as the liquid-phase catalyst. Under the synergistic effect of electrochemical reactions and liquid-phase catalysis, PH3, H2S, and HCN were finally oxidized to PO43-, elemental sulfur, SO42-, CO2, and N2. HO·, H2O2, and HO2·generated in the electrochemical process had a strong oxidative ability. Influencing parameters such as the catalyst types, electrochemical conditions (electrode voltage, electrode current, etc.), access sequence and mono/bi-component catalyst were investigated. The law of interaction among PH3, H2S and HCN components in the purification process was analyzed in detail. At a constant voltage of 3 V, the optimal purification effect was achieved when Pd/Cu catalyst was used, PH3, H2S and HCN purification rates were approximately 84 %, 100 % and 95 %. Furthermore, the system is more stable when mimicking the removal of PH3, H2S, and HCN from tail gas. This study proposes a practical strategy for removing poisonous and hazardous industrial waste gases at the same time. It significantly reduces hazardous exhaust emissions and enables cleaner industrial processes.