Preparation Of Double-network Graphene Oxide/cellulose Aerogel And Its Adsorption Properties For Water Pollutants

Textile printing and dyeing wastewater has the characteristics of deep color,high alkalinity and high content of organic pollutants.It is a kind of industrial wastewater that is difficult to treat.Graphene oxide(GO)is a new type of two-dimensional carbon nanomaterial.It contains abundant oxygen-containing functional groups,delocalized ?electrons endowed by a special six-membered ring structure and a huge specific surface area.This unique structure makes GO exhibiting excellent physical and chemical properties,and strong adsorption capacity for pollutants containing conjugated systems in water.However,GO is prone to agglomeration when dispersed in an aqueous solution,resulting in a significant decrease in its specific surface area,thereby affecting the adsorption performance.In addition,the size of GO is small and the sheet layer is more flexible.It is difficult to complete the separation,recovery and reuse of GO,using traditional methods such as filtration and centrifugation.This exhibits the problem of secondary pollution,which limits its large-scale application in the field of adsorption.Therefore,in this paper,using the high specific surface area and excellent physical and chemical properties of GO,we introduced cellulose molecules to overlap the GO sheet into a three-dimensional framework structure,while increasing active sites and constructing graphene oxide/cellulose(GO/CA)materials with high adsorption performance and three-dimensional double network structure.The main research work could be summarized as follows:(1)Graphite oxide was prepared by the improved Hummers method,and the GO dispersion was obtained by ultrasonic treatment.Using GO as the substrate,introducing cellulose molecules,comparing and optimizing the distribution ratios of the composite materials,selecting the best conditions,and preparing graphite oxide and cellulose with a mass ratio of 1:5,1:10 and 1:15 GO/CA framework material through the sol-gel method.(2)The introduction of cellulose molecules prevents the stacking and agglomeration of GO sheets and acts as a supporting structure to promote the formation of a three-dimensional porous structure of GO.The crystal structure of the aerogel was observed by X-ray diffraction(XRD)and Raman spectroscopy,and the functional group changes of the composite material were observed by X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FT-IR),and using automatic specific surface area and porosity analyzer to detect and analyze specific surface area and pore size.The results showed that GO and cellulose molecules were successfully recombined and assembled into a three-dimensional structure through hydrogen bonding.At the same time,cellulose molecules introduce a large number of active groups,which is beneficial to provide adsorption sites for the adsorption process.(3)We compared the adsorption performance of GO,cellulose aerogel and GO/CA framework materials on cationic dyes(methylene blue,rhodamine B,crystal violet,methyl orange)and aromatic organic pollutants bisphenol A(BPA)by Ultraviolet spectrophotometer(UV).The results show that when the mass ratio of graphite oxide to cellulose is 1:10,GO/CA has the most excellent adsorption performance.The equilibrium adsorption capacity for crystal violet is as high as 199.79 mg/g,and the equilibrium adsorption capacity for BPA can reach 298.43 mg/g.It is found that GO/CA2 exhibits the most excellent adsorption performance.In addition,this article also explored the influence of different external conditions(adsorption time,initial p H value of the pollutant solution)on the adsorption performance of GO/CA.We also used adsorption kinetics and adsorption isotherm models to fit the experimental data to reveal the interaction mechanism between GO/CA framework materials and water pollutants.