Preparation And Properties Of Functionalized Polyacrylonitrile Fiber

In this paper,polyacrylonitrile fiber(PAN)was used to obtain high-performance pre-oxidized polyacrylonitrile fiber(oPAN)by high-temperature calcination in air or nitrogen atmosphere,and then a series of functional polyacrylonitrile fibers were prepared by hydrothermal method.oPAN fiber,chitosan and citric acid were used to prepare carboxylated polyacrylonitrile-based carbon nanofibers(oPAN@C)by one-step hydrothermal method,in which chitosan was used as a biomass carbon source to introduce a hydrophilic functionalized carbon layer.Due to the negative-charged carboxyl functional group on the surface of the material,oPAN@C exhibits extremely high responsiveness to cationic contaminants.In the adsorption experiments,the maximum adsorption capacity for MB and Pb²⁺by oPAN@C was 153.37 mg·g^-1 and 143.27mg·g^-1,respectively.The oPAN@C retains high removal efficiency after 5 cycles and has good recyclability.The protonated zirconium-based metal organic framework/polyacrylonitrile composite(U-PAN)was synthesized in situ by hydrothermal method using oPAN fiber as a carrier.The zeta potential on the surface of U-PAN material is related to the amount of acetic acid:the more the acetic acid added,the stronger the positive charge of the material,which produce the stronger adsorption of anionic dye.Dye adsorption experiments showed that the adsorption process followed a pseudo-second-order model.In the anion-cation mixed dyes adsorption experiment,U-PAN showed excellent selective adsorption ability for anionic dyes.Aminated polyacrylonitrile fibers(N-PAN)were first prepared by hydrothermal reaction of PAN with ethylenediamine,and the urease is effectively immobilized on N-PAN by Schiff base reaction with assist of the cross-linking agent glutaraldehyde.Fiber samples with different urease loadings were successfully obtained.The immobilized urease fibers(Ur-PAN)exhibited excellent removal performance for urea.According to the Langmuir model fitting data,the maximum removal capacity of Ur-PAN for urea solution was as high as 440.52 mg·g^-1.In the urea/L-phenylalanine mixed solution experiment,the urea removal amounts of the three immobilized materials Ur-PAN were 95.66,96.01 and 98.66 mg·g^-1,respectively,while for the L-phenylalanine was only 1.23,1.01 and 1.74 mg·g^-1,respectively.Thus,Ur-PAN has good enzymatic activity and stability.