Preparation And Properties Of Tio₂ Supported Cellulose/sio₂ Composite Photocatalytic Materials

Cellulose aerogel is a porous,very low-density solid material that,due to its special internal space structure,gives it excellent physical properties,especially excellent adsorption properties.The aerogel material has a porosity of more than 95%and a density of only 0.12 to 0.23 mg·cm^-3,so it has wide applications in many fields such as catalysis,adsorption,and heat insulation.Cellulose aerogels are limited in their application in wet environments due to their poor hydrophobicity and strength.Therefore,cellulose aerogel reinforcement and hydrophobic modification need to be solved.TiO₂ photocatalysis technology is an emerging water treatment technology.It is widely used in solar energy conversion and photocatalytic treatment environment due to its non-toxic and environmentally friendly properties.In this article,the aerogel is modified,and the aerogel is used as the carrier to support the photocatalyst.It is used in the treatment of oily wastewater,which makes full use of the advantages of high porosity,low density and high adsorption rate of cellulose aerogel.Catalysis has broad application prospects in the treatment of floating oil pollution in water.The preparation of cellulose/SiO₂ composite aerogel material is based on waste paper cellulose,and the cellulose is hydrophobically modified with methyltrimethoxysilane（MTMS）as the silicon source,ethanol and dimethyl sulfoxide are used as solvents.The cellulose/SiO₂ composite hydrogel was prepared by sol-gel method,and then aged to form cellulose/SiO₂ composite solid gel.Finally,freeze-dried to obtain cellulose/SiO₂ composite aerogel（CSA）with good performance in all aspects.The hydrophobicity and oil absorption properties of the composite aerogel were studied by different cellulose content,different hydrolysis pH and different solvent ratios,and the hydrophobic principle was analyzed.The obtained aerogels were prepared by scanning electron microscopy（SEM）,X-ray diffraction（XRD）,infrared analysis（FT-IR）,specific surface area analysis（BET）,contact angle measuring instrument and thermogravimetric analysis（TGA）.The results show that the material consists of macropores,mesopores and micropores.The lowest density is 0.107 g·cm^-3,which has good hydrophobic properties.The static hydrophobic contact angle can reach 148.5°.The mechanical properties are good and can reach 50%.After compression,100%recovery,the material has good adsorption performance,through the adsorption performance of gasoline,diesel,pump oil,crude oil,found that adsorption 60 s can reach saturation,adsorption oil can reach 12.7 times its own quality,thermal stability is improved.The TiO₂ photocatalysts doped with rare earth metal La were prepared by sol-gel method.The photocatalytic materials were microscopically analyzed by X-ray diffraction（XRD）,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The effect of calcination temperature,catalyst addition amount,catalyst crystal form and catalyst particle size on its catalytic performance was studied.La-TiO₂ was loaded into cellulose/SiO₂ composite aerogel by impregnation method to obtain La-TiO₂-supported cellulose/SiO₂ composite aerogel material（La-Ti-CSA）,which was studied for oil absorption in water with natural light.For the degradation ability of oil,gasoline,diesel,pump oil and crude oil were selected to study the oil absorption capacity of oil absorption.Taking crude oil as an example to study its photodecomposition ability uwith natural light,the purpose of adsorption-degradation was achieved.The migration path of carriers was studied by UV-vis DRS and electrochemical workstation.The catalytic degradation mechanism was obtained.The metal La extended the visible absorption band edge of TiO₂ and made the absorption spectrum In the infrared direction,the doping of La changes the band structure of TiO₂,reduces the carrier resistance（impedance reduction）,and effectively separates the hole-electron pair,which greatly increases the photocatalytic activity of TiO₂.It absorbs in the visible light region and can utilize more light energy,which improves the utilization efficiency of light.The La-Ti-CSA obtained by the research can float on the water surface,can absorb and collect the thin oil layer encountered by the water surface,and decompose the oil stain through the photocatalyst without secondary pollution and environmental protection.