A thermally activated double oxidants advanced oxidation system for gaseous H2S removal: Mechanism and kinetics

A thermally activated double oxidants (Oxone/H2O2) advanced oxidation system is used for gaseous H2S removal. Several fundamental issues for H2S removal, e.g., process parameters, products, synergy activation mechanism of free radicals, desulfurization mechanism and kinetics were systematically explored. Compared with single oxidant activation systems, double oxidants activation system shows higher free radical yields and H2S removal efficiencies. Temperature demonstrates a critical role in producing free radicals and removing H2S. With the raise of Oxone concentration (0 to 0.6 moL/L), the H2S removal efficiency is first increased greatly, and then is slightly increased. A double change is discovered for removing H2S when H2O2 concentration or activating temperature is increased continuously (optimization values are 0.8 moL/L and 338 K, respectively). Removal efficiency of H2S is increased through raising pH value and liquid-gas ratio, while is declined via raising H2S content. Sulfate and elemental sulfur are determined to be the main final products, and no by-products are formed. Oxidation by & BULL;OH and SO4-& BULL; is confirmed to be the primary pathways for removing H2S. Kinetic study discovers that the H2S removal process belongs to a pseudo-first-order reaction and complies with two kinds of kinetic characteristics (i.e., fast reaction and medium reaction) depending on different experimental operating conditions.

Automated summary

A thermally activated double oxidants (Oxone/H2O2) advanced oxidation system was used for gaseous H2S removal. Several fundamental issues for H2S removal were systematically explored, and it was found that the double oxidants activation system showed higher free radical yields and H2S removal efficiencies. Temperature played a critical role in producing free radicals and removing H2S.