The Preparation And Application In Water Treatment Of Graphene/Titanium Dioxide Nanotubes Composite Photocatalytic

Due to high production and consumption of dye in our country, studies on treatment of dyewaste water have been closely watched. It is difficult to be controlled because of the toxicity,complexity, high chromaticity, and poor biochemical degradability of dye wastewater.Photocatalytic oxidation technology is a new effective treatment to control dye wastewater. Ascommon photocatalysis material, TiO2has many advantages, including strong oxidizing,non-toxic, stable chemical properties and cheap, but the quick restructuring of electronic–holepairs and poor photoresponse for visible light limited its application. Adding exogenous tomodification of TiO2can effectively extend the utilization efficiency of sunlight and improve theperformance of photocatalytic oxidation, which has great research value in the field ofenvironmental material.Firstly, used the commercial TiO2nanoparticles as titanium source, prepared the modifiedtitanium dioxide nanotubes (TNT) by hydrothermal method; Secondly, prepared graphite oxideby the improved Hummers method, and then achieved the reduction of graphene oxide and theload of TNT during the hydrothermal progress; finally graphene-titania nanotube (GN-TNT)composite photocatalyst were obtained. The aim is to use the high specific surface area and highelectron mobility advantage of graphene to improve composite photocatalyst surface area andreduced electron hole pair recombination rate, in order to improve the photocatalytic propertiesof materials, and expand the scope of its response for visible light. Physicochemical properties ofthe prepared photocatalyst were characterized by means of TEM, AFM, XRD, FT-IR, TGA, BETand UV-VIS. At the end, RBK5and MB dyes and As (III) were selected as the target pollutantsto study photocatalytic activity of GN-TNT photocatalyst under UV and visible light, andachieved some meaningful results:(1) In this study, graphite oxide was prepared according to the modified Hummers method,then reduction of the graphene oxide and load of TNT were achieved during the hydrothermalprogress to obtain graphene-titania nanotube (GN-TNT) composite. Composites prepared in thisstudy have outstanding thermal stability and photoresponse for visible light, its specific surfacearea was as high as254m2/g.(2) The adsorption experiments for MB dyes showed that GN-TNT nanocomposites withhydrothermal method (HM) and alkali hydrothermal method (AHM) both possessed strongadsorption for MB, and the adsorption capacity is much higher than other common or similar adsorbents.(3) Photocatalytic experiments of RBK5dyes with different series of GN-TNT compositephotocatalyst under UV light:20%GN-TNT composite photocatalyst showed the highestefficiency of removing RBK5. At the same time, the degradation efficiency of RBK5increasedwith the decrease of pollutant concentration and increase of catalyst dosage. The preliminaryexperiments under400nm light indicated GN-TNT composite photocatalyst had excellentphotocatalytic performance under visible light irradiation.(4) GN-TNT composite materials as photocatalyst can oxide As (III) to As (V) under visiblelight. In addition, with the increased concentration of As (III), the degradation efficiencydecreased.(5) Experiments of hybrid system with RBK5dye and As (III): GN-TNT compositephotocatalyst still has excellent degradation efficiency for both RBK5dye and As (III) ion undervisible light, which can be up to100%and80%respectively. Compared to single system,degradation efficiency of RBK5dye and As (III) both decreased in hybrid system.