Preparation Of ZnO/C And Ag/ZnO And Their Enhanced Photocatalytic Performance Study

Dye waste water,such as Methyl Orange(MO)and Methylene blue(MB)can cause serious contamination to human and environment if they are not treated properly.Adsorption and photocatalysis methods are two main approaches that are being used in dye waster water treatment.Adsorption method is the most used physical treatment which work by remove dye molecule from one place to another.However,dye waste water can not be completely degraded by this method.Photocatalytic degradation received great amount number of rearch and study because of its excellent dye removal ability,convenience and low costing.Nano sized Zinc Oxide(ZnO)got lots of attention as the nano technology soaring.It is a typical wide band-gap semi-conducting material with excellent performance and high surface area.What's more,because of its unique surface effect,quantum effect,dielectric confinement effects,as well as high photoactivity,non-toxicity,good reusability,it has been widely used in water treatment domain.Six kinds of ionic liquids were prepared in our study.The solubility of cellulose in respective ionic liquid were studied.As we know,loading ZnO on carbon matrix can avoid its aggregation.And light use efficiency of ZnO can also be improved.In this study,ZnO/Carbon composites with different ZnO loading contents were prepared by using BMIMCl ionic liquid as solvent and NaOH as coprecipitator,which can be used for photocatalytical degradation of organic dye polluants in water.All of the obtained catalysts exhibit good photocatalytic activity under UV irradiation,and ZC 6 with 27.6% ZnO loading showed the highest photochemical activity with a discoloration rate of 90.4% toward to MO aqueous solution.The morphology,structure,crystalline and spectrometric features of these novel nanocomposite were characterized by XRD,XPS,UV-Vis,FT-IR and SEM analysis for better understanding of their physic-chemical properties,application mechanism and performances.We also prepared Ag loading ZnO nanocomposite to enhance ZnO photoactivity and hinded electron-hole recommbination.Ag particles act as electron sinking center and the optimal loading capacity(5 %)was determinded.The optimal catalyst dosage is 60 mg.The photodegradation process is a pseudo first order reaction.XRD,XPS,UV,PL,EIS analysis were performed to character its structure and property.Finally,we discuessed the mechanism of photocatalysis by using XPS and we also determined the free radicals type in photodegradation process by adding radical trapping agent AO,BQ and TBA.We found that both hydroxyl radical and superoxide radical play important roles in MB degradation.