Fe2+/heat-coactivated PMS oxidation-absorption system for H2S removal from gas phase

A Fe2+/heat-coactivated PMS (peroxymonosulfate) oxidation-absorption system for H2S removal from gas phase in a gas/liquid impinging stream reactor was proposed. The feasibility of the technology, process parameters, free radicals. products, and mechanism of H2S removal in the developed coactivated system were systematically studied. Results demonstrated that in removal process of H2S, the free radicals such as SO4-center dot and (OH)-O-center dot that are produced by Fe2+/heat coactivation of PMS and thermal activation of PMS play a major role, and the SO4-center dot and (OH)-O-center dot that are produced by Fe2+ activation of PMS plays a supplementary role. The free radicals yield by the synergistic activation between Fe2+ and heat is far greater than that of the individual activation (i.e., Fe2+ or heat). Product analysis showed that elemental sulfur and sulfate were the major oxidation products of H2S removal using the Fe2+/heat co-activation system. H2S removal in the coactivation system was greatly promoted by increasing concentration of PMS and liquid-gas ratio, while it was weakened by raising concentration of H2S and addition of SO2, NO or CO. Increasing Fe2+ concentration, solution pH value and thermal activation temperature induces a double influence on the removal of H2S. Finally, the after-treatment scheme of the removal products in the developed system is also discussed.