Molecular Simulation Study On Natural Gas Desulfurization Performance Of Metal-Organic Frameworks And Oil/Water Separation Mechanisms In Surfactant Solution

Metal-Organic Frameworks (MOFs) have emerged as a new family of nanoporous materials. Compared with other conventional adsorbents, MOFs have many unique structural features, making them a research focus in many fields such as gas storage, separation, catalysis and bio-medicines. In addition, as a series of surface active compounds, surfactants not only can greatly decrease the surface tension of aqueous solutions, but also enhance their solubilization, dispersion and wetting abilities. In contrast to experimental techniques, computational chemistry can be utilized to rapidly explore the structure-property relationships of materials and reveal the microscopic mechanisms related to macroscopic behaviors, thus providing theoretical foundation further studies. Therefore, computational chemistry method was used in this thesis to study the performance of MOFs for natural gas desulfurization and the mechanisms of oil drops detached from the hydrophobic solid surface in the surfactant solution. The contents of this paper mainly includes:1. Adsorption-based separation and purification performance of UiO-66(Zr)-(COOH)2 material for natural gas, which has a good physicochemical properties. Compared to the mixture simulation results, ideal adsorbed solution theory (IAST) can be used to well describe the adsorption behavior of H2S/CH4 in the material. At the same time, the results show that the MOF has a good ability for H2S/CH4 separation, and is superior to the existing several typical MOF materials, making them exhibit potential applications in industrial desulfurization of natural gas.2. H2S/CH4 separation performance of pure UiO-66(Zr)-(COOH)2 membrane and mixed matrix membranes (MMMs) containing this MOF. The results show that both the pure MOF membrane and the MMMs can be regarded as promising candidates with good selectity/permeability for H2S/CH4 systems.3. Mechanisms of oil drop detached from the hydrophobic solid surface in the surfactant solution. By changing the type and chain length of surfactants as well as the interactions between head/tail and oil/water molecules, the results reveal that there exist three different mechanisms of the oil drop detached from the hydrophobic solid surface, which agree well with the experimental observations.