Selective H2S/CO2 Separation by Metal–Organic Frameworks Based on Chemical-Physical Adsorption

The removal of hydrogen sulfide (H2S) is essential in various industry applications such as purification of syngas for avoiding its corrosion and toxicity to catalysts. The design of adsorbents that can bear corrosion of H2S and overcome the competitive adsorption from carbon dioxide (CO2) is a challenge. To obtain insight into the stability and adsorption mechanism of metal–organic frameworks (MOFs) during the H2S separation process, 11 MOF-based materials were employed for H2S capture from CO2. Density functional theory, molecular dynamic studies, and dynamic separation experiments were used to investigate selective H2S/CO2 separation. Most of these MOFs showed one-off high capacity and selectivity to H2S. Complete reversible physical adsorption was proven on Mg-MOF-74, MIL-101(Cr), UiO-66, ZIF-8, and Ce-BTC. Incomplete reversible adsorption occurred on UiO-66(NH2). Disposable chemical reaction happened on HKUST-1, Cu-BDC(ted)0.5, Zn-MOF-74, MIL-100(Fe) gel, and MOF-5. Using breakthrough experiments, UiO-66, Mg-MOF-74, and MIL-101(Cr) were screened out to present promising performance on the H2S capture. The present study is useful to identify and design suitable MOF materials for high-performance H2S capture and separation.