Synthesis And Properties Of Modified Chitosan/Graphene Oxide Composites

Recently,the adsorption methods have been widely used as an effective technique for the treatment of dye wastewater.Various treatments are developed with the purpose of dye pollution including adsorption,membrane separation,ozonation,flotation,sedimentation,electrolysis.Among these methods,adsorption is the most widely used one method owing to its ease of high efficiency,economic feasibility and simply operating.The adsorption capability is closely related to adsorption material.Natural biomasses have attracted considerable attention for adsorbent due to biodegradability,biocompatibility and renewability.Chitosan is an abundant polysaccharide in the nature.Owing to possessing numerous chelating groups including hydroxyl and highly reactive amino groups,chitosan has been extensively applied as a high-efficiency adsorbent to eliminate dyes and metal ions.Graphene oxide(GO)has reactive oxygen functional groups in the form of epoxy,hydroxyl,and carboxyl groups in its surface and edge plane,which makes it become a high-performance adsorbent.Besides,melamine is grafted into chitosan skeleton,which can generate a novel hybrid material with increased efficiency for adsorption.In this paper,formaldehyde cross-linked chitosan/graphene oxide(CSFGO)composites were prepared by lyophilization.Utilizing FTIR,XRD,SEM,TG and XPS,we characterized and analyzed the morphologies,microstructures and chemical components of the material.The CSFGO was used as the adsorbent for methyl orange,and the effects of the graphene oxide content,the adsorption time and the initial concentration of dye on the adsorption properties of the composites were studied.In addition,the CSFGO composites were pyrolyzed to produce CSG electrode materials.Then,CSG electrode materials were characterized by electrochemical characterization,and CSG-80 exhibited an eminent specific capacitance(209 F g-1).The novel laminated chitosan-melamine-GO(CSMFGO)composites were fabricated as highly effective adsorbent for methyl orange.Utilizing FTIR,XPS,XRD,SEM and TG,we characterized and analyzed the morphologies,microstructures and chemical components of the material.According to the analysis results,we proposed mechanism of synthesis of CSMFGO monoliths.Meanwhile,we investigated the effects of the content of melamine,the content of graphene oxide,adsorption time and the initial concentration on the adsorption for MO,and also evaluated adsorption kinetics.The results showed that CSMFGO-80 had a maximum adsorption capacity of 738 mg g-1 under mild conditions.On the basis of the correlation coefficients(R2),the fitting results are closer to pseudo-second-order equations and Freundlich isotherm.