Oxidative removal of gaseous hydrogen sulfide by a dual ions-dual oxidants coupling activation system

Abstract

A gaseous hydrogen sulfide (H2S) oxidative removal technology by a dual ions-dual oxidants coupling activation system (i.e., Cu2+/Fe2+/persulfate(PS)/H2O2 coactivation system) was put forward. The fundamental issues, mainly including H2S removal performance, process parameters optimization, products, free radicals, synergy mechanism and desulfurization mechanism were studied systematically in a bubble column reactor. The study indicates that compared with Fenton system and non-coupling activation systems, the new dual ions-dual oxidants coupling coactivation system shows much higher free radical yield and H2S removal efficiency owing to significant synergistic activation effect. Higher concentrations of Cu2+ or Fe2+ greatly increase the H2S removal efficiency. With the increase of PS concentration, H2O2 concentration or reagent pH value, the H2S removal efficiency is first enhanced, and afterwards slightly declined. The H2S removal efficiency is declined via increasing operating temperature, gas flow rate and contents of H2S, SO2, NO and CO, and is almost not affected by content of Hg0. Sulfate, CuS and elemental sulfur are determined to be the products of H2S removal, and no by-products are produced after the reaction. Oxidation via ·OH and SO4-· plays a crucial role in H2S removal, which is proved to be the primary pathways of H2S removal. Finally, the recovery strategy of the products is discussed preliminarily.