COMPUTATIONAL SCREENING OF ZEOLITIC MATERIALS FOR CO2 AND H2S SEPARATION

This work presents theoretical molecular computations performed for CO2 and H2S adsorption evaluation on several zeolite molecular structures using density functional theory (DFT). Therefore this work analyzes the feasibility of the studied zeolites, for CO2 and H2S adsorption, to take the adsorption energy as a criterion for adsorption capacities and using transition state theory as a tool for predicting which sorbents are favored after both thermodynamic and kinetic computations. The calculated values predicted that MEL zeolite is the molecular structure that most favors the adsorption of CO2 and H2S. In addition, analysis using frontier orbital theory predicted that the CO2 and H2S adsorption mechanism was performed with zeolites acting as Lewis acids or electron acceptors. For CO2, the interaction took place between one oxygen atom of the CO2 gas and a silicon atom from the zeolite. The interaction mechanism with H2S predicted that it took place between one sulfur atom as a Lewis base and a zeolite silicon atom. It was concluded that this porous material screening, which is based on quantum electronic structure calculations, could be used for CO2 and H2S removal from fluid mixtures mostly found in the oil and gas industry.