Spectroscopic investigation, cage occupancy, and gas storage capacity of hydroquinone clathrates formed with H2S-N2 and COS-N2 binary gas mixtures

Abstract

The objective of this investigation was to determine whether hydroquinone (HQ) can form clathrate compounds with two sulfides (hydrogen sulfide (H2S) and carbonyl sulfide (COS)) at their diluted concentrations. Hydroquinone samples obtained at ambient temperature and at two pressures (40 and 80 bar) for binary gas mixtures consisting of H2S-N2 and COS-N2, were analyzed using solid-state 13C NMR and Raman spectroscopy. An elemental analyzer was also used to obtain quantitative information regarding the kind and amount of gas captured in the solid samples. Results show that H2S can be concentrated within the solid clathrate from H2S-containing gas, while COS is little captured after reaction with the COS-containing gas. This suggests that the HQ clathrate can be used to remove H2S, and that selective separation can be achieved when two sulfides of H2S and COS coexist. On the basis of the calculated cage occupancies of the gas components in the solid clathrate, the enclathration preference of the gas components used in this research was found to be the order of H2S>N2>COS.