Functional Modification And Adsorption Properties Of Electrospun CA Nanofiber Membrane

Cellulose acetate（CA）was used as raw material to design nanofiber membrane structure.Cellulose acetate nanofiber membrane（CANM）was prepared by electrospinning.After three-step modification and grafting modification,CANM was endowed with specific functional groups.Finally,two new adsorbents,carboxyl modified cellulose acetate electrospun nanofiber membrane（CANM-COOH）and amino modified cellulose acetate electrospun nanofiber membrane（CANM-NH₂）,were obtained.The main research contents are as follows:1.Using CA as raw material and acetone/DMAc/water（7:2:1）as mixed solvent,the optimum spinning conditions of CANM were obtained by orthogonal experiment:the concentration of spinning solution was 10wt%,the spinning voltage was 18 k V,the extrusion speed was 0.2 m L/h,and the receiving distance was 18 cm.SEM,FTIR,TG,DSC and other performance testing methods were used to characterize CANM before and after modification.CANM-COOH was prepared by deacetylation,sodium periodate oxidation and sodium chlorite oxidation,and its carboxyl content was 1.074mmol/g.CANM-NH₂ was obtained by deacetylation,oxidation by Na IO₄ and surface grafting modification,and the amino grafting rate was 9.951%.2.The effects of p H value,initial concentration,contact time and temperature on the adsorption of Cu²⁺and MB by CANM-COOH were studied.Experimental results show that Langmuir isothermal adsorption model,quasi-first-order kinetic model and quasi-second-order kinetic model are all suitable for studying the adsorption behavior of Cu²⁺by CANM-COOH,and the maximum adsorption capacity of Cu²⁺by CANM-COOH is 76.39 mg/g,with both physical adsorption and chemical adsorption.In the whole process of adsorption of MB by CANM-COOH,Langmuir isothermal adsorption model and quasi-second-order kinetic model are most suitable for studying the adsorption behavior of MB by CANM-COOH.The maximum adsorption capacity of MB by CANM-COOH is 311.52 mg/g,and the adsorption process is mainly chemical adsorption.CANM-COOH adsorbed Cu²⁺for five times,and the adsorption efficiency remained above 83%.The adsorption efficiency of MB remained above 78.78%after five cycles of adsorption.3.The effects of p H value,initial concentration,adsorption time and temperature on the adsorption of Cu²⁺and CR by CANM-NH₂ were studied.The experimental results show that Freundlich isothermal adsorption model and quasi-second-order kinetic model are most suitable for studying the adsorption behavior of Cu²⁺by CANM-NH₂.The theoretical maximum adsorption capacity of Cu²⁺by CANM-NH₂ is 80.06mg/g,and the adsorption process is mainly chemical adsorption.In the whole process of adsorption of CR by CANM-NH₂,Temkin isothermal adsorption model and Elovich kinetic model are most suitable for studying the adsorption behavior of CR by CANM-NH₂.The theoretical maximum adsorption capacity of CANM-NH₂ for CR is 558.65mg/g,and the mechanism is chemical adsorption with low adsorption rate.The adsorption efficiency of Cu²⁺remained above 85%after five cycles of adsorption.The adsorption efficiency of CR was still 63%after 4 cycles of adsorption.