Effect of Humidity on the Sorption of H2S from Multicomponent Acid Gas Streams on Silica-Supported Sterically Hindered and Unhindered Amines

• DOI: 10.1021/acssuschemeng.0c02012
• Publication Date: 2020-06-30T20:14:41Z
• Authors: Claudia N. Okonkwo; Hanjun Fang; David S. Sholl; Johannes E. Leisen; Christopher W. Jones
• Keywords: Physisorption

The sorption of H2S on a silica-supported sterically hindered secondary amine and supported unhindered tertiary is investigated using fixed bed breakthrough experiments. In situ Fourier transform infrared spectroscopy computational analysis are used to elucidate the structure surface species formed during humid sorption. Additionally, cyclic stability amine-functionalized silica sorbent assessed NMR spectroscopy, N2 physisorption, elemental analysis. For all sorbents under dry conditions, physisorption amines led low capacities, but strongly chemisorbed formed, which leads an increase in capacity. These findings by density functional theory (DFT) calculations, support formation stable HS– presence H2O. As result bound species, require temperature swing sorption–desorption cycles for efficient regeneration conditions studied, with swings gas failing effectively desorb H2S. competitive H2S/CO2 mixed (CH4/CO2/H2S/H2O), selectivity over CO2 demonstrated from kinetic factors, reaction barriers playing major role conditions. Overall, framework organic moieties maintained both after extended exposure. results this work confirm positive effect humidity capacity amines.