| The economic and social development makes water shortage and pollution increasingly serious in the world.In recent years,the removal of pollutants in water has attracted extensive attention.Cellulose-based composite aerogel has unique advantages in the removal of pollutants in water due to its lightweight,stable physical and chemical properties,easy regeneration,and natural degradation.However,hydroxyl is the main active group for the cellulose surface limiting its application,and the adsorption capacity needs to be improved.This thesis with carboxyl nano cellulose as the research object,with the cellulose derivatives,functional polymers,and inorganic nanoparticles montmorillonite composite,through a simple solution blend and freeze-drying technology preparation,has good mechanical properties and adsorption performance of fiber composite aerogel,studying the characteristics of its application in the field of sewage disposal.(1)Three kinds of cellulose-based aerogels,CMC/O,CMC/CNF-C,and CMC/CNFs,were prepared by using CNFs,CNF-C and CMC as raw materials,and polyethylene glycol diglycidyl ether(PEGDE)as a crosslinking agent.The experimental results show that CMC/O and CMC/CNF-C have better adsorption properties for MB than CMC/CNFs under the same experimental conditions,indicating that the interaction between cellulose and its derivatives and methylene blue dye molecules is mainly electrostatic attraction.The results of adsorption model fitting show that the adsorption process of CMC/CNF-C for MB conforms to the quasisecond-order kinetics model and Langmuir isotherm model,and the adsorption is monomer and chemisorption.(2)Cellulose-based composite aerogel(CEHP)modified by HPEI was prepared using CNF-C as a matrix,PEGDE as a crosslinking agent,and hyperbranched polyethyleneimine(HPEI)as a modifier.Compared with the unmodified cellulose aerogel,the addition of HPEI can improve the CR adsorption capacity of the composite aerogel,and the adsorption capacity can reach 2122 mg/g.The adsorption process conforms to the quasi-second-order kinetics model and Langmuir isotherm model.In addition,the concentration of cellulose solution had a great influence on the formation of aerogel pores,resulting in the adsorption performance of the aerogel prepared with the concentration of 0.8% CNF-C solution(CEHP-0.8)was significantly lower than that of the aerogel prepared with the concentration of 0.4% CNF-C solution(CEHP-0.4).It indicates that the solid content of aerogels should be controlled in a low concentration range.(3)CMP cellulose composite aerogel was prepared from CNF-C,MMT,and PEI.MMT was mixed into the cellulose skeleton structure as a reinforcing agent,and PEI was combined with cellulose through an amidation reaction.The synergistic effect of hydrogen bond and chemical bond gave good mechanical properties to CMP aerogel.At the same time,the addition of PEI adjusted the surface charge distribution of cellulose material and improved the adsorption performance of CMP aerogel for Congo red dye.When the addition of PEI was 30%,the best adsorption capacity reached 3114 mg/g.The adsorption process of congo red dye by CMP-30 composite aerogel is more consistent with the quasi-second-order kinetic model and Langmuir isotherm model,indicating that the adsorption is monomolecular chemisorption.In addition,after hydrophobicity treatment of CMP-30 aerogel with octylchlorosilane,the hydrophilic and lipophilic properties of the aerogel were transformed into hydrophobic and lipophilic properties. |
