Preparation Of Triacetate Reverse Osmosis Membrane And Its Antibacterial Modification Research

Reverse osmosis is widely used in the fields of seawater desalination,brackish water desalination and sewage treatment due to its advantage of low energy consumption,high desalination and high yield of water.As the first polymer materials which was used to manufacture reverse osmosis membrane,cellulose acetate(CA)is still possession of a certain market area of reverse osmosis membrane because of its high desalination rate,non-toxic and great chlorine resistance.CA molecule is made of ?-anhydroglucose units and linked by C-O-C polymer linear structure,that makes it be degradated easily by the microorganisms in complex water condition.Therefore,it is necessary and valuable to research and development of antibacterial cellulose acetate reverse osmosis mebrane.In this paper,we used three different way to modify the cellulose triacetate membrane and hoping to endue it with antibacterial functional.First of all,different paranmeters which had great influence on the membrane performance were adjusted to obtain the best ones for fabricating reverse osmosis with high performance.Then,blending method and layer-by-layer(LBL)self-assembly technology were used to modify CTA reverse osmosis membrane to make it antibacterial.Fourier transform infrared spcctroscopy(FTIR).X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM)were used to characterize the elemental composition,chemical structure and morphology of the membrane products.Membrane performance tests(Flux-Retcention)tests showed that the addition of chitosan does not exceed 1.00 wt%,the blend membrane can maintain a high rejection rate,while the antibacterial test showed that E.coli and S.aureus Antibacterial rates were 72.5%and 51%,but membrane modified by LBL technology have no antibacterial activity duo to weak binding of antibacterial components.In view of the insufficient of physical ways,this study further modified CTA menmbrane by controlling the quantitative hydrolysis and etherification reaction to graft quaternary ammonium antibacterial on the surface of membrane.Chemical bonds firmly bond makes modified membrane products to maintain long-term,efficient and stable antibacterial activity at the same time,due to antibacterial groups will not shed film caused by the performance degradation and membrane damage.The chemical structure,composition and membrane properties of the modified membrane products were analyzed by different characterization methods.The results showed that compared with the physical method,the cellulose acetate reverse osmosis membranes obtained by chemical grafting were better in maintaining high antibacterial activity.At the same time,the modified membrane remained high salt rejection and flux,proving that membrane performance was not affected.So as to cellulose triacetate reverse osmosis membrane functional modification provides a theoretical basis and technical means.