The Preparation Of Cellulose Triacetate Ultrafiltration Membrane And Modified Research

In recent years, ultrafiltration （UF） has extensively used in the field of bio-separationbecause of its distinct advantages, such as negligible phase change involved, low operatingpressure, ambient or relatively low operating temperature and so on. However, because ofthe serious fouling caused by adsorption and deposition of bio-macromolecules on themembrane surface and inside the membrane pores, the efficiency and application ofultrafiltration is largely limited. Therefore, hydrophilic membranes have become thepreferred choice to avoid protein fouling.Here we use the basic material of cellulose triacetate （CTA） to produce the UFmembrane by the phase transformation technique. We also discuss some of factors inproducing proeess such as the kind of organie solvent，the concentration of polymer，theadditives, which all can influence the membrane’separation character. The result revealsthat CTA ultrafiltration membrane has good filtering performance when NMP is chosen assolvent, and the polymer concentration is10%as well as the concentration of PEG is2.5wt%.Cellulose triacetate （CTA） ultrafiltration membranes were prepared via phaseinversion technique using hydrophilic TEMPO-Oxidized Cellulose Nanofibrils （TOCNs） asmodifying agent. The permeation performance of the prepared membranes was evaluated interms of pure water flux （PWF Ji）, protein rejection （Rm） and flux recovery ratio （FRR）.Mem brane surface morphology and cross-sectional structures were characterized byatomic-force microscopy （AFM） and scanning electron microscopy （SEM）, respectively.XRD was performed in order to investigate the interactions between membrane components.Meanwhile, the effects of TOCNs concentration on hydrophilicity of the membrane surfaceand mechanical properties were also examined. The experimental results indicated thatCTA/TOCNs composite membranes exhibit significant differences in surface properties andintrinsict properties due to the addition of TOCNs.In order to improve the hydrophilic and flux of CTA membranes, hydrophilicinorganic nanoparticles were also used as additive. CTA/Al₂O₃membranes with a series ofdifferent content of inorganic nanoparticles were prepared by immersion precipitation phaseinversion process. The objective of this work was to study the influence of the Al₂O₃addition and the Mw of PEG on the membrane structure and membrane properties including permeation performance, antifouling property, surface hydrophilic, mechanicalproperties and so on.Now the membrane separation technology has emerged as an attractive and effectivetechnique in the treatment of wastewater and groundwater containing toxic metal ions,since it offers concentration and separation of metals or valuable chemicals without achange of state and without the use of chemicals or thermal. In this work, the preparationmethod and adsorption behavior of xanthated cotton fiber were investigated. The xanthatedcotton fiber can be prepared with two steps, at first, it is alkalized, and then xanthated. Asthe xanthated cotton fiber was unstable, it was oxidized to sulphur in the moist air anddecomposed to CS2in the acidic medium. But its complex compounds with heavy metalions were stable. The xanthated cotton fiber can be used to absorb a lot of heavy metal ions,such as Cu（Ⅱ）, Zn（Ⅱ）, Ni（Ⅱ）, Cd（Ⅱ）. The xanthated cotton fiber is a useful adsorption agentand be used to concentrate trace heavy metal ions in analytical chemistry.