Preparation And Research Of Degradation Performance On TiO₂/Graphene Oxide Composite Photocatalyst

In order to seek a kind of Functional Ecomaterial to modify the polluted water environment and degrade the organic pollutants efficiently in some simple and feasible ways,and this kind of Functional Ecomaterial can improve its utilization efficiency and it can be used in the actual wastewater treatment process.This paper focus on the removal efficiency of the organic pollutants,rhodamine B?RB?,fulvic acid?FA?and oxytetracycline?OTC?,from model wastewater by the action of catalysis and adsorption.Graphene oxide?GO?was prepared by classic modified Hummers method,and TiO₂/GO composites with efficient activity were prepared by one-step colloidal blending methods using GO as the carrier loaded onto TiO₂.The morphology of GO and composites were structurally characterized using a Fourier transform infrared spectroscopy?FTIR?,a X-ray diffraction?XRD?,as well other ways.Meanwhile,the effect of the composites on the properties of photocatalytic and adsorption on RB,FA and OTC was investigated.The results showed as following:?1?Pure Graphene oxide?GO?with fewer layers and more thinner thickness was prepared by modified Hummers method.When TiO₂ was added to the reaction system,in the ultra-sonication and stirring condition,TiO₂/GO composites with efficient activity were prepared.TiO₂ distribute themselves to GO layers uniformly,and they connected with each other by covalent bond in the composites.?2?Investigating the removal effects which the composites degrade the targeted pollutants on the different dosage gradient condition.In a certain range,increasing the dosage of catalyst can improve adsorption and degradation efficiency which the catalyst degrade the targeted pollutants effectively.When the compound catalyst is overused,there are found the masking effect in the reaction system leading to the declines of the catalytic efficiency.It is discovered in this research that the decolourization rate is faster,the TOC removal ratio is larger and the removal efficiency is more stable in dosing 50mg/L of the composites than in other dosage.The best dosage of the composites degrading the RB solution is 50mg/L by thinking comprehensively.?3?In the photocatalysis stage,GO and TiO₂ from TiO₂/GO composites generate the synergy,and the UV removal rate of the composites degrading the RB,FA and OTC increases with the reaction continuing in a certain degree.The UV removal rate of FA is 97.56% as well the RB and OTC reach to more than 99%.The TOC removal rate of RB,FA and OTC is 66.72%,57.92% and 71.45% respectively,which improves greatly comparing with pure TiO₂.When the dosage is 50mg/L,and finally,the order of the removal rate is OTC>RB>FA.It is showed that the best dosage of the composites degrading the targeted pollutants is different.?4?After using 5 times repeatedly,the UV554 removal efficiency of degrading RB is more than 99%,and the TOC removal efficiency is about 55%.TiO₂/GO composites can recycle more times better.?5?In the adsorption stage,the process of TiO₂/GO composites adsorbing three targeted pollutants matches with the pseudo-second order reaction kinetics curve,and fitting the adsorption quantity Qe in equilibrium are 253.8mg/g,302.11mg/g and 115.47mg/g respectively.The process of TiO₂/GO composites adsorbing RB and FA matches with the Freundlich isotherm model,and the process of composites adsorbing OTC matches with the Langmuir isotherm model.According to the Langmuir isotherm model,fitting the maximal adsorption capacity Qm are 523.56mg/g,483.09mg/g and 112.48mg/g,Q_m?RB?> Q_m?FA?> Q_m?OTC?.Because of ?-? conjugation from the structure of the composites,electrostatic interaction and ion interaction between composites and the targeted pollutants,the adsorption process is promoted.