Selective Removal Of Nitrophenol And Green Conversion Of CO₂ By Biquaternary Ammonium Functionalized Fiber

With the rapid development of economy and the continuous promotion of industrialization,while improving people's lives,the discharge of a large number of organic pollutants causes water pollution,and the emission of greenhouse gas carbon dioxide causes air pollution,which not only seriously affects the ecological balance,but also brings harm to human health.The development of new materials to achieve the selective removal of organic pollutants in water and the recovery and utilization of greenhouse gases have attracted wide attention of scholars and become a reseach hotspot.In this thesis,using Polyacrylonitrile fiber as carrier,biquaternary ammonium functionalized fibers were designed and synthesized for selective removal of nitrophenol in water and green catalytic conversion of carbon dioxide.The tertiary amine functionalized fiber PANPF,was prepared by immobilizing N,N-dimethylpropylene-1,3-diamine onto Polyacrylonitrile fiber.On this basis,two kinds of mono-quaternary functionalized fibers and four kinds of biquaternary ammonium functionalized fibers with different carbon chain length were prepared.The successful preparation of the functionalized fiber was proved by FTIR,EA,XRD,XPS,SEM,TGA and mechanical strength.The adsorption properties of six kinds of functionalized fibers were investigated by using 4-nitrophenol as a model compound,and it was determined that the biquaternary ammonium functionalized fiber with C3 chain length had the best adsorption performance.The selective adsorption properties of PANBQAS-3F for different compounds were studied systematically,and the adsorption selectivity of functional fibers was regulated by adjusting the p H value of the solution.On this basis,a possible adsorption mechanism was proposed.Then 2,4-dinitrophenol with the best adsorption performance was used as a model compound to explore the effects of weight gain,dosage,p H,time,temperature and concentration on the adsorption properties of PANBQAS-3F fiber,and the adsorption kinetics,isotherm and thermodynamics were studied systematically.In addition,the flow chemistry and recycling performance of functional fiber PANBQAS-3F were investigated.The results showed that the removal efficiency of functional fiber was more than 99%after ten times of reuse.The biquaternary ammonium functional fiber PANBQAS-3F with the best adsorption performance was used to catalyze the cyclization of carbon dioxide and epoxides.The reaction conditions were optimized.The results showed that the yield was as high as99%when the amount of PANBQAS-3F fiber catalyst was 0.5 mol%,the reaction temperature was 80 ~oC and the reaction time was 18 h.