Preparation And Performance Study Of Cellulose Acetate-based Polyionic Liquid Membrane

With the rapid development of industrialization,environmental pollution has become more and more serious,especially water pollution.The emission of oily wastewater and dye wastewater,not only greatly affect the survival of aquatic organisms,but also seriously threats to human health.Membrane water treatment technology is an effective method used to treat sewage.However,the composition of the sewage is very complicated,the single-function membrane has great limitation in the sewage treatment.Therefore,it is very significance to develop multifunctional water treatment membrane.In this paper,functional groups of ionic liquids with good chemical stability and low flammability were grafted into the molecules of cellulose acetate to obtain polymer-based polyionic liquids,which were then prepared into membrane.FTIR,NMR,XPS,TG,SEM,and Zeta potential were used to characterize the structure and properties of the membrane products,and the adsorption properties,antibacterial properties,and oil-water emulsion separation properties of the samples were investigated.Specific research contents are as follows:?1?First of all,cellulose acetate was dissolved in DMF and acetylated with bromoacetyl bromide at low temperature to obtain cellulose bromoacetoacetate?CA-Br?.CA-Br was dissolved in DMF and reacted with 1-methylimidazole and ammonium fluoborate,then,the[CAmim][BF4]was obtained.The CA/[CAmim][BF₄]blend membranes?CA-PIL membranes?were prepared via the non-solvent induced phase separation?NIPS?process.The thermal stability and water flux of the CA-PIL membranes were reduced,while the pressure resistance and BSA rejection rate were improved with the introduction of ionic liquid functional groups.?2?The adsorption effect of CA-PIL membrane on Congo red dye was investigated,and the isothermal adsorption models and kinetic models were used to describe the adsorption process.Furthermore,the adsorption mechanism was studied.The results showed the maximum equilibrium adsorption capacity was 82.36 mg/g,Freundlich model and Quasi-second-order kinetic model can well describe the adsorption process of Congo red by CA-PIL membrane.?3?The introduced ionic liquid functional group can be considered as a quaternary ammonium salt group.Therefore,the antibacterial performance of the CA-PIL membrane was also investigated in this paper.The research results showed that the bacterial inhibition rates of E.coli and S.aureus were 83.23%-94.81%and 96.86%-100%,respectively.The antibacterial effect on S.aureus was better.?4?Based on the electronegativity and hydrophilicity of the membrane surface,the separation effect of the CA-PIL membrane on the vacuum pump oil/water emulsion was investigated.The research results showed that the separation efficiency can reach to 95.42%,and it displayed a certain oil-water emulsion separation ability.