Preparation And Performance Study Of Several Novel Cellulose-Based Carbon Aerogel

With the improvement of industrialization,more and more oily wastewater was discharged from human activities such as food,petroleum,textiles,and pharmaceuticals.The oily wastewater contains a large number of complex organic compounds with high biological toxicity and poor biodegradability,posing a serious threat to human health and ecosystems.Among many oil/water separation methods,the adsorption of oil pollutants by porous materials such as carbon aerogel is one of the most concerned technologies at present.In this paper,a variety of cellulose-based carbon aerogel were prepared by using low-cost and widely sourced cellulose as raw materials,and their oil/water separation ability was studied in detail.The specific research contents are as follows:（1）With hardwood pulp as raw material,NMMO·H₂O and DES mixed solvent（DNS）as solvent,regenerated cellulose-based carbon aerogel（DRC_xA）were prepared by sol-gel method.The prepared DRC_xA has excellent oil/water separation performance,and its adsorption capacity for different oils and organic solvents can reach 17.0-50.1times of its own mass.In addition,the carbon aerogel can be recovered by combustion and distillation.Its adsorption amount remains unchanged after 10 cycles,showing good reusability.（2）By controlling the dissolution time of hardwood pulp in DNS to control the proportion of linear natural cellulose and lamellar regenerated cellulose in samples,natural cellulose/regenerated cellulose-based carbon aerogel（NM/R_xCA）was successfully prepared.The results showed that the NM/RCA after dissoluting 5 min had low density(9.3 mg cm^-3),high porosity（98.1%）,and high specific surface area(768.89 m² g^-1).In addition,the stress and height can still maintain 85.9%and 80.5%of their initial values after 100 cycles of 80%strain compression.NM/RCA was superhydrophobic（water contact angle,WCA=151.2°）and can remain relatively stable under harsh conditions.NM/RCA can effectively separate oil and organic solvent from oil/water mixtures,and the sorption capacity can reach 65.1-133.2 g g^-1.After 25distillation cycles,it can still maintain 91.89%of the initial adsorption capacity.Moreover,continuous oil/water separation can be carried out through equipment such as pumps,with a flux of 11718.8 m^-2h^-1 and a separation efficiency of 99.91%.（3）By using tubular kapok fibres（KF）instead of linear hardwood pulp,kapok/regenerated cellulose-based carbon aerogel（KR_xCA）was successfully prepared.The results showed that when regenerated cellulose accounted for 10%of the total mass,the density of the prepared KR₁₀CA was as low as 3.8 mg cm^-3,and the porosity was as high as 98.9%.The adsorption capacity for different oils and organic solvents was137.5-371.7 g g^-1.After 100 50%strain compression cycles,the stress and height of the aerogel are almost unchanged.Continuous oil/water separation is carried out through equipment such as pumps,with a flux of 21972.7 L m^-2 h^-1 and a separation efficiency of 99.95%.In addition,KR₁₀CA-800 has excellent conductivity and can be used as a pressure sensor after carbonization at 800℃,.After 1000 cycles,it shows good current response stability.