A Study On Semiconductor Nanometer TiO₂ Photoelectrocatalytic Degradation Of Acetochlor And Related Analysis Issues

Under the action of certain wavelength light and the condition of suitable solution composition, semiconductor nanometer TiO2 can produce the strong oxidizing valence band hole and the free radical, which can oxidize the organic pollution to CO2, H2O and other non-toxic substances, thus reducing the concentration of pollutants in water to achieve the purposes of decontamination water. However, the titanium dioxide powder is difficult to recycle and low degradation efficiency in the process of waste water treatment, so we studied different forms of immobilized semiconductor titanium dioxide in the degradation of organochlorine pesticides acetochlor-related analytical issues. The main contents include:(1) In this paper, highly ordered TiO2 nanotubes arrays were fabricated on the surface of titanium using electrochemical anodic oxidation method in fluoride-based electrolytes containing phosphate. Perepared TiO2 nanotubes were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS) and electrochemical tests method. The result indicated that prepared TiO2 nanotubes is about 2.5μm long, tube wall thickness of 15nm and the diameter of 70-100nm. The samples are composed of anatase phase with a fraction of rutile phase. UV-Vis DRS analysis shows that the band gap energy of TiO2 nanotubes is 3.16eV. Photoelectrochemical tests results indicate that a higher photoresponse current is obtained under 3V bias.(2) Under the 3V forward bias, we studied the photoelectric synergistic catalytic degradation behavior of acetochlor in solution using the TiO2 nanotubes arrays electrode prepared by anodic oxidation. And the factors that might influent the photoelectrocatalytic process were investigated, such as the initial pH value of solution, the electrolyte solution composition, the dissolved oxygen as well as the concentration of target degeneration compound.(3) The suspension of Ag-doped semiconductor nanometer TiO2 were filtered and piled up on the surface of a water treatment microfiltration membrane (MF, aperture for 0.2μm), which can be assembled into a recycling photocatalyst for degradation study of acetochlor. The results show that Ag-doped TiO2 nanowire filtration membrane has significant improve effect in solving traditional microfiltration membrane fouling organisms and the membrane flux.