Preparation, Characterization And Application On A Novel Separation Membrane-α-Cellulose Membrane

Nowadays, a novel method for preparing cellulose fibre is developed in the world. It directly dissolves pure cellulose, not using conventional chemical converting methods, and keeps the cellulose native characteristics. Based on the idea of directly dissolving cellulose, which has been successfully achieved in the textile industry, the preparation of cellulose membrane using N-methylmorpholine N-oxide as solvent and the physical, chemical, and permeation performance of the prepared cellulose membrane were studied in this thesis.First, the factors influencing the structure and performance of the prepared cellulose membrane such as solvent, the temperature and concentration of casting solution, the temperature and composition of coagulation bath were investigated by theoretic analysis and experimenting. And the novel technique of preparing membrane by directly dissolving cellulose was realized. The prepared cellulose membrane keeps the chemical structure of native cellulose and presents particular space structure. It has the crystallinity close to native cellulose, far more than that of the conventional cellulose membranes using different methods prepared. It has excellent mechanical performance, heat resistance and chemical resistance. It can keep stabilization at 150癈 and endure the influence of 5wt.% H2SO4 or 18wt.%NaOH solution.In this thesis, the permeation and separation characteristics of a gas through "dry" and "water-swollen" cellulose membranes were examined. The results show that there are differences in transport properties between the udry" and "water-swollen" cellulose membranes. The "water-swollen" cellulose membrane presented high permeation rates for acidic gases. And the permeability of CO2 was as high as 120barrer; the separation factors of CO2 over N2, CPi* and H2 are 50, 30, and 15 respectively. The function of water on the cellulose membrane was also revealed by comparatively studying the gas permeability of water, cellulose acetate membrane, benzoylated cellulose membrane and polysulfone membrane both in "dry" and "wet" states. Moreover, in the thesis, the liquid permeability of the prepared cellulose membrane was investigated and the effect of swelling on the liquid permeability of the prepared cellulose membrane was studied in some details.Based on the results, the removal of 862 from SO2/N2 mixture using the prepared "water-swollen" cellulose membrane was also investigated.