Chemical Modification Of Cellulose Membrane And Study On The Gas Permeability Of Modified Membrane

Sulfur dioxide is always being one of the most dangerous polluting gases, while existing processing methods all endure disadvantages such as poor desulfurization efficiency and difficult sulfur-contained castoff disposal. Therefore, many scientists are developing new technologies that are more efficient, less costly and more environment-friendly, among which membrane separation technology has been expected as the most promising desulfurization method. In this article different modified cellulose membranes that possess high sulfur dioxide permeability and excellent mechanical performance were achieved through a-cellulose membrane modification.At first a gas permeability test system that can measure the intrinsic gas permeability of different membrane materials was developed and applied in the measurements of gas permeation performance of original dry a-cellulose membrane. The results show that the dry a-cellulose membrane possesses very little gas permeability (about 0.003 barrer).The gas permeation performance of a-cellulose membrane that contained dimethyl sulfoxide (DMSO) was evaluated. It was proven that after being DMSO contained the sulfur dioxide permeability of a-cellulose membrane would show obvious increase, and when it contained saturated DMSO its sulfur dioxidepermeability could be as high as 6800 barren While with DMSO losing its sulfur dioxide permeability would decrease quickly, and this value would decrease to 580 barrer after three days.The a-cellulose membranes were chemically modified through Michael addition reaction by being immersed into three different solutions including emulsion, ethanol solution and DMSO solution that contained phenyl vinyl sulfoxide and sodium hydroxide. The results show all chemical modifications brought little change to the membrane morphology and it still possesses a homogeneously dense structure. Compared with the original a-cellulose membranes, after being chemically modified its sulfur dioxide permeability would increase greatly ,the membrane modified by emulsion had a maximum value as high as 13000 barrer. What is more, the results show that the sulfur dioxide permeability of modified cellulose membrane was very steady in a test period more than one week.Different from the other two modified cellulose membrane, the sulfur dioxide permeability of emulsion modified cellulose membrane would decrease with the increase of permeation pressure difference that was consistent with the dual-adsorption and dual -movement theory. This was tentatively explained by that the emulsion modification could bring the a-cellulose membrane a higher modification degree.