H2S catalytic removal at low temperature over Cu- and Mg- activated carbon honeycombs

A series of monometallic and bimetallic Cu/Mg oxide-based structured catalytic sorbents were synthesized by impregnation of extruded activated carbon honeycombs and tested for the purification of simulated biogas from H2S at room temperature. Dynamic H2S (100ppmv) removal tests were run at short contact time under moist conditions in the presence of O2 to compare sulfur capture capacities and to investigate kinetic aspects of the oxidation reactions involved in the mechanism at varying the composition of the active phase. Fresh, exhausted and thermally regenerated honeycomb catalytic sorbents were characterized by N2-adsorption, PSD, XPS, TG-MS to shed light on the specific nature of S-species formed upon catalytic oxidation, the maximum capacity and the efficacy of a simple thermal regeneration treatment at 600 °C. Under moist conditions, the surface chemistry resulted dominated by the basic nature of MgO, and bimetallic CuMg catalytic sorbents show fast H2S removal rates and large S-capacity coupled to easy and complete regenerability.