The photocatalytic degradation of ortho, para and meta-nitroanilines (ONA, PNA and MNA) was investigated by Ag-TiO2 suspension. The effect of some parameters such as the amount of photocatalyst, irradiation time of UV light, flow rate of O2, pH, and temperature for the Ag-TiO2 photocatalyst was also examined. Degradation of amines was small when the reaction was carried out in the absence of photocatalyst, and negligible in the absence of the UV light. Degradation rate of aniline derivatives decreases with increasing O2 in the system. The effect of pH indicated that effective degradation occurred in alkaline conditions. Degradation kinetics of these aromatic amines can be described by Langmuir-Hinshelwood equation and shows pseudo-first order law.

In this study, iron-oxide (magnetite) synthesized by co-precipitation method and binary TiO2-Fe3O4 and ternary rGO-TiO2-Fe3O4 nanocomposites (called GTF) prepared by hydrothermal method. Crystal structure and bonds, studied by X-ray diffraction (XRD) and FTIR analysis, respectively. The morphology of samples was studied by SEM. The average size of nanoparticles estimated ~12. 3 nm and saturation magnetization of nanocomposites obtained by VSM, was 40. 26 emu/g. The photocatalytic activity of synthesized nanocomposites determined by degradation of methyl orange under UV light irradiation. The ternary nanocomposites showed ~98. 7 % degradation of methyl orange which has a remarkable improvement compared to TiO2-Fe3O4 binary nanocomposites with 84 % degradation.

In this paper, photo catalytic degradation of commercial textile azo dyes catalyzed by titanium dioxide and modified titanium dioxide with Ag metal (1% w/w) in aqueous solution under irradiation with a 400 W high-pressure mercury lamp is reported. The effect of various parameters such as irradiation time of UV light, amount of photo catalyst and flow rate of oxygen, pH and temperature for the Ag-TiO2 photo catalyst were investigated. Kinetic investigations of photo degradation indicated that reactions obey improved Langmuir-Hinshelwood model and pseudo-first-order law. The rate constant studies of photocatalytic degradation reactions for Ag-TiO2 and TiO2 photo catalysts indicated that in all cases the rate constant of the reaction for Ag-TiO2 was higher than that of TiO2.

TiO2/Magnetit and TiO2/Nd/Magnetit were prepared and used for photocatalytic decomposition of the methylorange as a pollutant. TiO2 and TiO2/Nd were prepared by sol gel method and were characterized using XRD, FT IR and TEM. The prepared catalysts were deposited on magnetite surface to have a catalyst with magnetite core. So the catalyst can be separated easily from the waste solution by a magnet. Comparing the photocatalytic activity of TiO2/Magnetit and TiO2/Nd/Magnetit showed that doping the TiO2 by Nd increases the catalytic activity. Acidity of the waste has also promising effect on catalytic activity and the time needed for methylorange decomposition was decreased in low pHs. Complete decomposition of the methylorange was confirmed by LC MS.

Immobilization of catalysts on the surface of some inert supports makes the recovering step easier. Because of the specific physicochemical properties, zeolites are good candidate as catalyst supports. In this study, zeolite X was synthesized by natural kaolin and TiO2 was incorporated into zeolite phase by impregnation method. Degradation of Safranin Orange, methylene blue and 2, 4-dinitroaniline was studied in the presence and absence of ultraviolet radiation. The effect of experimental parameters including TiO2 loading, photocatalyst amount, irradiation time, pH and initial concentration were studied. Adsorption and photodegradation of the pollutants followed first-order kinetics. Adsorption isotherms were analysed using Langmuir and Freundlich models. The higher activity obtained for TiO2 supported onzeolite X is attributed to the greater adsorption of the pollutants on the zeolite surface as compared to pure TiO2.

Silver doped TiO2 nanoparticles were prepared by combination of sol-gel and arc discharge methods in liquid. The Ag/TiO2 nanoparticles were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM) and ultra violet-visible absorption spectroscopy (UV-Vis). The visible light photocatalytic activities were successfully demonstrated for the degradation of Rhodamine B (Rh. B) as a standard organic compound under the irradiation of 90 W halogen light for 2 h. The results revealed that the Ag/TiO2 nanoparticles extended the light absorption spectrum toward the visible region and significantly enhanced the Rh. B photodegradation under visible light irradiation. 0.05 gr Ag/TiO2 nanoparticles exhibited highest photocatalytic efficiency. It has been confirmed that the Ag/TiO2 nanoparticles could be excited by visible light (E<3.2 eV). The significant enhancement in the Ag/TiO2 nanoparticles photocatalytic activity under visible light irradiation can be ascribed to the effect of doped noble metal Ag by acting as electron traps in TiO2 band gap.