Preparation And Properties Of Functionalized Regenerated Cellulose/GO Composite Aerogels

In this work,cellulose biomass-bamboo powder was used as the raw material,and ionic liquid[Emim]OAc was used as the solvent to form cellulose solution.Cellulose aerogel（CE）and cellulose/graphene oxide composite aerogel（CG）were prepared by adding a certain amount of graphene oxide（GO）into the cellulose solution.Given the abundant hydroxyl and reactive functional groups on the surface of GO and cellulose,CE and CG aerogels were ideal precursors for chemical modification,resulting in a series of derivatives with specific properties.Bamboo powder was pretreated with alkali and dissolved in ionic liquid[Emim]OAc to form a uniform cellulose solution.CE aerogels with different cellulose contents and CG composite aerogels with different GO contents were successfully prepared by solution mixing-regeneration and freeze-drying processes.CE aerogel has lower density and excellent mechanical properties,and its specific surface area was as high as 209 m²/g.The CG composite aerogel showed a network structure and a three-dimensional porous structure.In adsorption experiments,the maximum adsorption capacities of CG4.5 composite aerogel for MB and TC was as high as245.1 mg/g and 80.0 mg/g,respectively.After six cycles,it still showed good removal ability.Manganese dioxide-supported CE aerogel（MCE）and CG aerogel（MCG）were prepared by in-situ redox reaction between cellulose and GO components of CE and CG aerogels and KMn O₄.The Mn O₂ nanoparticles on the surface of MCE and MCG aerogels have three-dimensional petal-shaped spherical nanostructures,which provide fast transport channels and rich active sites for the diffusion and removal of MB.In adsorption experiments,MCE and MCG aerogels significantly increased the adsorption capacity of MB.The maximum adsorption capacity was 108.3 mg/g and80.5 mg/g,respectively,and the removal efficiency was as high as 96.66%.After multiple consecutive adsorption-desorption cycles,the removal efficiency of MCE aerogel did not decrease significantly and the structure was intact.CE and CG aerogels were functionalized with 1,4-butyl sultone as a modifier under mild reaction conditions to prepare sulfo-functional aerogels（SCE and SCG）.SCG4.5 aerogel has a very high surface area（170 m²/g）,and its adsorption capacity for MB and TC has been greatly improved.The maximum adsorption capacities were as high as 421.94 mg/g and 163.40 mg/g,respectively.For simulated wastewater containing MB and TC,the removal efficiency of the new SCG aerogel adsorbent was as high as 99.56%and 99.98%.Furthermore,its adsorption capacity was not apparently deteriorated after seven cycles for MB and ten cycles for TC while the original structural integrity was almost maintained.