Capture of H2S and SO2 from trace sulfur containing gas mixture by functionalized UiO-66(Zr) materials: A molecular simulation study

With the advantage of high selectivity, moisture stability, thermostability, acid gas resistance, high sorption capacity, and low-cost regenerability, serials of UiO-66(Zr) metal-organic frameworks (MOFs) are considered as promising materials in gas adsorption and purification applications. In this work, we carried out molecular simulations to study the adsorption and membrane separation performance of non-modified UiO-66(Zr) and its functionalized derivatives in sulfur capture from binary sulfur containing gas mixtures. Our results indicate that UiO-66-(COOH)2 and UiO-66-COOH show better adsorption performance in H2S and SO2 capture than other functionalized derivatives. The isosteric heat of adsorption at infinite dilution and radial distribution functions display the existence of strong interactions between hydrophilic functional groups and H2S and SO2. The joint effect of hydrophilism and strong polarity of functional groups promotes the adsorption of H2S and SO2. Both UiO-66-(COOH)2 and UiO-66-COOH are also expected to be ideal membrane candidates for H2S separation because of superior permeation selectivity and permeability.