Study On Preparation And Photocatalytic Activity Of Graphene-based Nano-ZnO Composites

As the rapid development of science and technology,people realized the environmental problems which urgent need to handle were more and more serious.Photocatalytic decomposition is a new method to dispose organic wastewater,however,how to prepare the catalyst which has superior photo-catalytic activity and improve the sewage treatment process became the new targets the researchers pursued and explored.In this paper,the composite catalyst was made by using solvothermal method utilizing graphite oxide,zinc nitrate hexahydrate and sodium hydroxide as raw material,which the graphite oxide was made by using the modified Hummers method though graphite powder.Using different metal ions on Zinc oxide-graphene doped to obtain the composite catalyst metal ion doped.SEM,XRD,FT-IR were utilized to characterized the morphology and structure of the composite catalyst.First,the prepared ZnO-graphene nanocomposites were used for catalysts,and methyl orange solution was used for the analogue wastewater.We studied the photocatalytic activity of the catalysts which were prepared under different conditions by degradation experiments.Moreover we optimized the synthesis conditions through the orthogonal experiment.The results showed that the best prepared conditions were loading graphene 1%,initial pH 11,temperature 160 ?,time 20h,The decolorization rate was 94.74%,and it had higher photocatalytic activity than pure ZnO.Second,different metal doping ZnO-graphene composite catalysts were used for degradation experiments,and we compared their catalytic activity.The results showed that Al doped catalyst had the best degradation effect.At the same time,we studied the effects of the doping amount of Al on photocatalytic performance.The results showed that when the atomic ratio was Al:Zn = 2:50,the degradation effect was the best.And the catalytic activity was the highest,and the decolorization rate was 97.14%.Finally,using the Al/ZnO-grapheme to catalytic degraded methyl orange simulated dye wastewater two UV lights that in power 40w irradiation.and orthogonal experiment were carried on to optimize the degradation process.Experimental results show that the optimal conditions were confirmed as follows:catalyst dosage 0.1g,initial pH 13,initial concentration 20mg/L,reaction time 2.5h,the degradation ratio was 99.16%under this situation.