Study On The Preparation And Properties Of Sugarcane Cellulose Composite Aerogel

At present,petrochemical resources in various countries around the world are becoming more and more scarce,and environmental problems are also worsening.In this context,the development of recyclable and environmentally friendly biomass-based functional materials from a wide range of biomass resources has great theoretical significance and practical application value.Cellulose aerogels are the third generation of new porous materials,which not only contain the advantages of low density,high porosity and high specific surface area of traditional aerogels,but also inherit the characteristics of good biocompatibility and biodegradability of cellulose.Sugarcane contains a large amount of cellulose,with high orientation and hierarchical porous structure,which is an ideal raw material for the preparation of aerogels.In this project,sugarcane cellulose aerogels with high mesoporosity and excellent mechanical properties were mainly prepared by green and simple process methods.By functionalized modification,hydrophobic cellulose aerogels can be obtained.On this basis,the in-situ modification of sugarcane cellulose aerogels by MOFs can not only make up for their respective shortcomings,but also give play to their unique advantages and give new functions to composite aerogels.Relevant studies have shown that this aerogel has broad application potential in oil-water separation and catalytic degradation of organic dyes.（1）Highly mesoporous and compressible sugarcane cellulose aerogels were prepared by a simple and environmentally friendly top-down method.TEMPO/Na Cl O/Na Cl O₂oxidation under neutral conditions produces cellulose nanofibers through repulsion between carboxyl groups,while preserving the intact macrostructure of sugarcane.This orderly arrangement and highly mesoporous fiber network structure is freeze-dried to obtain anisotropic aerogels with high porosity（98.8%）and high compressive strength（0.53 MPa at 80%strain）.The specific surface area was further improved to 32.94 m²/g.Subsequently,silanization modification was carried out by chemical meteorological deposition（CAD）to obtain hydrophobic sugarcane cellulose aerogels with water contact angle as high as 145.73°,which can effectively adsorb oil and organic solvents（22.8-40.2 g/g）.In addition,porous aerogels maintain high oil absorption during multiple squeeze absorption.This new sugarcane cellulose aerogel offers potential possibilities for subsequent applications in efficient oil-water separation.（2）Based on the prepared high mesoporous and high compressive strength sugarcane cellulose aerogel,the in-situ modification of sugarcane cellulose by MOFs can not only effectively solve the problem of cellulose easy agglomeration,but also make up for the shortcomings of ZIF-67 powder with catalytic performance that are difficult to recover and poor stability,and a sugarcane cellulose composite aerogel with uniform loading ZIF-67 nanoparticles was constructed.The carboxyl group on the surface of sugarcane cellulose microfibrils is conducive to the interfacial coordination of polyvalent metal ions,thereby promoting the nucleation and growth of ZIF-67 in the cell wall of sugarcane fiber.The specific surface area of ZIF-67/sugarcane cellulose composite aerogel reached 217 m²/g,which has high pore accessibility and abundant active sites.It has excellent adsorption and catalytic degradation ability for organic pollutants in water,and the removal rate of methylene blue reaches 96.99%.In addition,ZIF-67@SNCA exhibits good recyclability and maintains a degradation rate of more than 90%after 5 adsorption-desorption cycles.The reaction mechanism of ZIF-67/sugarcane cellulose complex aerogel-activated PMS to degrade organic pollution was also discussed:mainly through the transition metal cobalt-activated PMS to produce oxidative active free radicals SO4^·-and^·OH.The research results provide a theoretical basis and technical support for the application of cellulose resources in water environment control and treatment.