Highly selective separation of H2S and CO2 using a H2S-imprinted polymers loaded on a polyoxometalate@Zr-based metal–organic framework with a core–shell structure at ambient temperature

Abstract

The removal of H₂S is extremely important for industrial development owing to its corrosiveness, toxicity and unpleasant odor. In industrial gas streams, however, the existence of CO₂ affects the removal efficiency of H₂S. To improve the removal of H₂S and recovery of sulphur resources at ambient temperature, we designed novel core–shell-structured H₂S imprinted polymers (PMo₁₂@UiO-66@H₂S-MIPs) based on the surface of UiO-66 modified by phosphomolybdic acid hydrate. Using H₂O as a substitution template for H₂S avoids the toxicity and instability issues of H₂S. The polymerization conditions, including the mole ratio of templates/functional monomers/cross-linkers, the amount of porogens, and the polymerization time, were optimized in detail. PMo₁₂@UiO-66@H₂S-MIPs exhibited high adsorption capacity for H₂S at ambient temperature even in the presence of water steam and showed excellent separation for H₂S/CO₂. Air purge regenerated PMo₁₂@UiO-66@H₂S-MIPs at 180 °C and O₃ treatment at room temperature can maintain their stable desulfurization ability for at least 6 cycles. The H₂S was transformed into sulphur after adsorption, and PMo₁₂ played the redox role in the desulfurization process. This work broadens the horizon for H₂S removal, separation and resource utilization.