| Because of a strong chemical stability, reusable, low price, titanium dioxide nanoparticle became the green environmental governance materials. Ti O2 photocatalytic degradation organic pollutants in water can be divided into suspension system and the load system. Coating Ti O2 onto the surface of soft magnetic nanomaterial material assembled into magnetic nanoparticle photocatalyst with shell nuclear structure, which not only keep the suspended state photocatalyst with high catalytic efficiency, but also recycle the photocatalyst using external magnetic field. However, magnetic nanoparticle photocatalyst with shell nuclear structure can produce induced optical dissolved during photocatalytic reaction, leading to the dissolution of the magnetic core and the decline of photocatalytic activity.Therefore, the magnetic photocatalyst with shell@shell@ nuclear structure become a hotspot.However, for the preparation of magnetic photocatalyst shell@shell@ nuclear structure, the current common synthetic methods are used calcining or drying [13-16]. The method to make the Ti O2 firmly loaded on the magnetic core surface. This leads to very complicated preparation steps, low formed material, prepared costly and difficult practical application. On the other hand, the magnetic powder photocatalyst state shell@shell@ nuclear structure, after drying polish, easy to destroy the integrity of the structure, resulting in a sharp decline in the photocatalytic activity; rather than through direct application of grinding, whether mechanical agitation or ultrasonic vibration, were unable to make it effective dispersion, serio usly affecting the photocatalytic efficienc y. If the load is applied directly after in situ synthesis good photocatalytic magnetic fluid carrier shell@shell@nuclear structure in the liquid phase conditions, will reduce the preparation steps and costs, to avoid drying or calcination brought shel @shell@ nuclear structure damage or the problem of poor dispersibility.Firstly, titanium sulfate as titanium source, by looking at its optimum conditions, the use of nuclear magnetic difference surface potential of nature to create favorable conditions for mutual electrostatic attraction between the Si O2@Fe3O4(SF) and Ti O2, using the hydrothermal reaction, by exploring the initial fluid p H, hydrothermal reaction time, temperature hydrothermal reaction, the liquid in situ prepared with high catalytic efficiency and good performance o f magnetic recovery Ti O2@Si O2@Fe3O4(TSF) photocatalytic magnetic fluid. Then tetraisopropyl titanate as titanium source, the use of low-temperature hydrothermal method coated Si O2@Fe3O4 in the liquid phase system particles, liquid-situ prepared Ti O2@Si O2@Fe3O4(Ti SF) photocatalytic magnetic fluid. Scanning electron microscopy(SEM), X-ray diffraction(XRD), Fourier transform infrared spectrophotometer(TI-IR), vibrating sample magnetometer(VSM) for the catalyst phase composition, morphology, surface properties, the magnetic properties were characterized. To simulate pollutant phenol, phenol degradation rate of COD and judge its photocatalytic activity to homemade magnetic recovery, study the life of its catalytic activity. Through research, the following conclusions:(1) The titanium sulfate as a titanium source, the initial p H value has a decisive influence on the Ti O2 load on the surface SF, in the hydrothermal reaction time was 4h, hydrothermal reaction was 180℃, the initial fluid p H was 11 is the best condition that Ti O2 load on the surface of SF with opposite charges and strongly bonded by electrostatic attraction. Ti O2@Si O2@Fe3O4(denoted TSF3) photocatalytic magnetic fluid prepared at the initial solution p H was11, hydrothermal reaction time was 4h, hydrothermal reaction temperature was 180℃ has good photocatalytic activity, the degradation rate of phenol was 87.21% and the COD degradation rate was 71.92%. TSF3 photocatalytic magnetic fluid has better photocatalytic life after cycle 5 times, phenol degradation rate decreased by 2.77%, the degradation rate of COD dropped by 0.73%.(2) The tetraisopropyl titanate as the titanium source, in the n(Ti):n(Si):n(Fe) molar ratio of 16:1.5:1 prepared Ti O2@Si O2@Fe3O4 photocatalytic magnetic fluid(denoted Ti SF3) has good photocatalytic activity for phenol degradation rate of 91.19% and COD degradation rate of 99.17%. Ti SF3 photocatalytic magnetic fluid has better photocatalytic life after cycle 5 times, phenol degradation rate fell 10.66%, the degradation rate of COD dropped by 1.57%.(3) Fe3O4 particle surface load Si O2 intermediate layer, and then the surface of the liquid in situ load Ti O2 photocatalyst prepared to become a photocatalysis magnetic fluid, both higher than the state of the magnetic powder photocatalyst light catalytic efficiency, but also to overcome the state of magnetic powder photocatalyst preparation process cumbersome, costly shortcomings.(4) TSF3 photocatalytic magnetic fluid with titanium sulfate as titanium source degradation of phenol and COD were less than Ti SF3 photocatalytic magnetic fluid with tetraisopropyl titanate as the titanium source. The fluid Ti O2 photocatalyst with titanium sulfate as titanium source degradation rate of phenol and COD were less than fluid Ti O2 photocatalyst with tetraisopropyl titanate as the titanium, indicating Ti O2 with tetraisopropyl titanate prepared with strong photocatalytic activity.(5) The fluid Ti O2 photocatalyst the degradation rate of phenol and COD is greater than the ratio of Ti O2 photocatalyst powder, indicating fluid Ti O2 photocatalyst has better photocatalytic activity, and reduce the complexity of the manufacturing process and the cost. |
