Construction And Separation Property Of Novel Mesoporous Silica Material/Polymer Mixed Matrix Membrane

Membrane separation technology is considered to be a key technology for sustainable development and green development because of its high efficiency,energy saving and environmental protection.The mixed matrix membrane?MMM?is dispersed in the polymer matrix by nano-scale inorganic filler.It combines excellent permeability and selectivity of inorganic membrane and the processability of the polymer membrane to achieve synergistic separation property,increasing the permeability and selectivity of MMM.In this thesis,several novel mesoporous SiO₂ nanomaterials are used as inorganic fillers to construct mesoporous SiO₂/polymer mixed matrix membranes to improve permeability and selectivity of gas separation and liquid separation.In this paper,anionic surfactant as template and tetraethyl orthosilicate as silicon source prepare mesoporous SiO₂ nanomaterials by the collaborative self-assembly,at different conditions of assisting structure directing agent,reaction temperature and reaction stirring speed,Characterized by FT-IR,SEM,BET and circular dichroism.,etc.The result shows that novel mesoporous SiO₂ nanomaterials with different morphology,specific surface area and chirality can be prepared at 0/10/20/30°C.The novel mesoporous SiO₂/PI mixed matrix membrane and SBA-15/PI mixed matrix membrane were prepared by in-situ polymerization method,Characterized by the TEM,FT-IR,Zeta potential and CO₂/N₂ permeation selectivity test.The result shows that the N₂permeation depends mainly on the amount of mesoporous SiO₂ material and its mesoporous channels;the CO₂ permeation is mainly determined by the hydrophilicity and polarity caused by the specific surface area of the mesoporous SiO₂ material,the dispersibility in the membrane,and the chiral mesoporous channel characteristics.When adding 5 wt%20°C-SiO₂,the mixed matrix membrane has the highest separation factor of 24.36,which was 17.13 times of the pure PI membrane.The novel mesoporous SiO₂ material/PVDF mixed matrix membrane and SBA-15/PVDF mixed matrix membrane are prepared by blending method,characterized by the SEM,TGA and water contact angles,water flux and anti-contamination performance tests,and DL-tryptophan separation test.The result shows that the thermal stability of the novel mesoporous SiO₂/PVDF mixed matrix membrane is improved,the porosity and average pore size increased,the hydrophilicity obviously increased,the water flux is significantly improved,and it has a certain separation effect for DL-tryptophan.When adding 5 wt%20°C-SiO₂,the mixed matrix membrane has the best modification effect.The pure water flux can reach 515.20 L·m^-2·h^-1,which is 6.45 times of pure PVDF membrane,and the rejection rate is 71.91%,the flux recovery rate is 80.93%,and the DL-tryptophan separation rate is13.89%.