| Cellulose is the most abundant organic biomass on earth,with biocompatibility,biodegradability,high specific strength and modulus.Cellulose carbon aerogel is light,porous and versatile,with adjustable cell structure.It can not only be used as a sustainable nano material and carrier,but also has a simple preparation process and low cost,heat insulation,catalysis,conductivity,fire resistance and other application fields,widely used in adsorption separation,drug sustained release,tissue engineering,conductive materials,capacitors and energy storage,anti-electromagnetic shielding interference,etc.In this thesis,sisal cellulose is used as the raw material to study the preparation and functionalization methods of cellulose carbon aerogel,and optimize the adsorption process applied to the separation of oil and water and the separation and extraction of metals such as selenium and lithium.The specific research contents are as follows:?1?Preparation of sisal cellulose carbon aerogels and its oil-water separation performance.The sisal leaves were used as raw materials to extract cellulose from sisal leaves by alkali treatment and bleaching treatment.The cellulose is constructed as a cellulose aerogel by freeze-drying techniques and then carbonized to obtain sisal cellulose carbon aerogels?CAs?.The adsorption performance test,hydrophobic performance test,chemical stability test and recycling performance of CAs on oil and organic solvents were studied.The results show that the adsorption capacity of CAs is 90-188 g·g-1,with good chemical stability and excellent cycle performance,which can effectively solve the water pollution caused by oil and organic reagent leakage.?2?Preparation of nano-Cu O-supported carbon aerogel composites and their performance in oil-water separation.Cellulose was extracted from sisal leaves as raw material,and nano-copper particles were loaded on the surface of cellulose by the reaction of copper acetate solution and hydrazine hydrate to obtain nano-copper-modified cellulose composite material.Then the nano-Cu O modified carbon aerogel composites?Cu O@CAs?were then prepared by oxidation,carbonization and freeze drying techniques.With the modification of nano-Cu O,the surface roughness of Cu O@CAs was increased,thus its superhydrophobic property was improved and the water contact angle was as high as 158°±2°.The results show that Cu O@CAs has excellent chemical stability and certain demulsification ability,and the filtration recovery rate of oil is as high as 92.3%.?3?Preparation of LDHs modified carbon aerogel composites and study on selenium extraction performance.The cellulose was extracted from sisal leaves,and the carbon aerogels were obtained by freeze-drying and carbonization.The surface of the carbon aerogels was coated with aluminum sol as precursor,and then the magnesium-aluminum layered double hydroxides?LDHs?were modified on the surface of the carbon aerogels by in-situ growth technique,and the product LDHs@CAs were obtained after calcination.The effects of p H,selenium concentration,adsorption time,competitive ions and adsorption dose on the adsorption performance of LDHs@CAs were investigated.The results showed that selenium was more easily adsorbed on LDHs@CAs under acidic conditions,and the maximum adsorption capacity of selenium ions on LDHs@CAs was as high as 73.6 mg·g-1.In addition,the adsorption of selenium ions on LDHs@CAs is mainly concentrated in the first 100 minutes.Therefore,LDHs@CAs with excellent adsorption performance has a good application prospect in the recovery of rare element selenium.?4?Preparation of sodium trititanate whisker modified carbon aerogel composites and study on its lithium extraction performance.The cellulose was extracted from sisal leaves,and then the carbon aerogels were obtained through the freeze-drying and carbonization step.The surface of the carbon aerogels coated with the titanium sol was prepared,and the final product sodium trititanate whisker-modified carbon aerogels?Na2Ti3O7@CAs?were obtained by calcination and acid treatment.The results show that Na2Ti3O7@CAs has abundant pore size and large specific surface area,and its maximum adsorption capacity for lithium ions can reach 40.35 mg·g-1.The saturated Na2Ti3O7@CAs can be efficiently regenerated by 0.5mol·L-1 HCl solutions and reused for lithium ions adsorption separation. |
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