Synthesis Of TiO₂/Go Nanocomposites And The Basic Study On Ultrafiltration Membrane

In recent years,thanks to the unique advantage, the photocatalysis technologywhich represented by TiO₂and membrane separation technology such asultrafiltration have attracted more and more attention by scientists. And they havebecome the focus of water treatment field. However, there are a lot of problemsduring the actual use of the two technologies for water treatment. Those problemslimit the applications of them in a large-scale industry. TiO₂photocatalysistechnology has its disadvantages: TiO₂produced the electrons and holes are easy tocompound in the light excited state, and quantum efficiency is low. Suspension TiO₂particles in the reactor is not easy to be recycled, which lead to the repeatedutilization ratio is low. Meanwhile, the ultrafiltration membrane used in the watertreatment process, easily affected by the membrane fouling problem. Therefore, thepreparation of the composite of photocatalytic TiO₂and the ultrafiltration membranewhich exert specialty of the two is a new thought to solve these problems.Considering on the above ideas, The gel-sol was used to prepare the TiO₂nanorod/rGO（TNRGO） composite photocatalyst innovatively in this study. Avariety of methods were used to characterize the morphology of TNRGO andphotocatalytic effect. And the photocatalytic mechanism of TNRGO was analyzed.With introducing TNRGO to polyvinylidene fluoride ultrafiltration membranesystem, TNRGO/PVDF composite ultrafiltration membrane was preparedsuccessfully by immersion precipitation phase shift method. And the influence ofTNRGO’s introduction on the structure and properties of ultrafiltration membranewas explored preliminarily.In the preparation of TNRGO with gel-sol, TiO₂nanorod had an average size. Thelength was L=150nm. The diameter was D=30nm, and the length to diameter ratiowas L/D=5. The crystal structure was anatase crystal. C-Ti chemical bonds existedbetween graphene and TiO₂nanorod. The shape of TiO₂was controlled by AdjustingpH value, and the optimum pH of rod-shaped structure was12. In the methyleneblue photodegradation experiment, TNRGO prepared by calcination treatment hadthe higher photodegradation efficiency than by the freeze-drying treatment. WhenGO was added to5%, there was the highest TNRGO photocatalytic activity.Considering to the preparation of TNRGO/PVDF composite ultralfiltrationmembrane, SEM, TEM, water flux testing，contact angle testing and UV-Vis DRStesting were used to characterize the structure, Morphology and performance. Theintroduction of TNRGO had a great influence on the morphology and properties of ultrafiltration membranes. Comparing to the pure PVDF ultrafiltration membrane,the membrane surface roughness increased, and the membrane hydrophilic, waterflux and entrapment rate were improved. When the GO content reached to5%,TNRGO had the best comprehensive performance.