Preparation And Properties Of Nanocellulose Aerogel From Spent Culture Substrate Of Auricularia

The rapid development of printing and packaging industrialization has produced a large number of printing and dyeing wastewater,it brings the serious environmental pollution.As the most valuable renewable resource with wide range of natural sources and low price in nature,cellulose is a friendly material for the preparation of functional aerogel adsorbent and provides the method to treat dye adsorption and removal.Agaric fungus residue is a kind of agricultural waste derived from wood,straw and other natural materials.It could be prepared the nano-cellulose aerogel by dissolution and regeneration,which provides good application potential for wastewater treatment.In this study,waste fungus residue(WFR)from Zhashui county city was used as raw material to prepare fungus residue nanocrystalline cellulose(FRNCC)by sulfuric acid(H2SO4)hydrolysis method.Combined with chemical cross-linking and silane modification technology,the ultra-light hydrophobic hydrophilic hydrogel was prepared.The adsorption effect of nano-cellulose aerogel on dyes and oil droplets were studied.The waste fungus residue was pretreaed with benzol and ethanol,NaOH alkaline washing and NaClO2 bleaching,the excess dissolved impurities,hemicellulose,lignin and other amorphous region structures were removed,and the crystallinity increased.The fungus residue cellulose(FRC)was treated under the temperature of 45℃ for 120 min with the 45%H2SO4 concentration,the slender needle-like nano-cellulose with crystallinity of 65.03%,yield of 67.25 wt%and diameter of 12 nm was obtained.After acidolysis,the small molecule glycosidic bond of cellulose was broken,the size became smaller,and crystallization zone was released,leading to the crystallinity and thermal stability improved.The 1-butyl 3-methylimidazolium chloride(BmimCl)ionic liquid was used as nano-cellulose dissolution system and N,N-methylene acrylamide(MBA)as crosslinking agent,the ultra-light aerogel with density of 34.41 mg/cm3-54.18 mg/cm3 and porosity of 97.83%-96.59%were obtained after freeze-drying.It showed the good adsorption capacity for the dye methylene blue(MB),the maximal adsorption capacity of aerogel with 10 wt%FRNCC can reach 36.297 mg/g.The adsorption of MB by fungus residue nano-cellulose aerogel is driven by the interaction between dye cationic groups and nano-cellulose anionic carboxyl groups and was the uniformly monolayer adsorption.Using methyltrimethoxy silane(MTMS)as modifier,hydrophobic hydrophilic hydrogels were prepared by liquid phase modification technology.The water contact angle was up to 105.8°,the adsorption capacity of oil and organic solvent could be improved obviously,and the adsorption capacty of aerogel to oil solvent was 22-28.The hydrophobic molecular chain of siloxane generated by MTMS hydrolysis reacted with hydroxyl group on the surface of cellulose to form the hydrophobic silanols,which could achieve oil-water separation effect.In conclusion,in this paper,nano-cellulose aerogel with good adsorption performance was obtained by dissolution-regeneration of waste fungus residue,which can achieve oil-water separation effect after modification.It provides the theoretical basis and technical support for the realization of resource utilization of agricultural by-products and adsorption removal of printing and dyeing wastewater.