Anatase N-Doped TiO2 nanoparticles were synthesized using ultrasound at low frequency and at room temperature. The samples characterized by techniques including XRD, TEM, HRTEM, FT-IR, XPS, and UV– Vis spectroscopy. XPS indicated the existence of nitrogen as an anion dopant within the TiO2 lattice. The solar photocatalytic activity of N-Doped TiO2 studied for the degradation and complete mineralization of Diclofenac (DCF). The results showed that the catalytic activity of the nanoparticles related to the operating conditions in the synthesis such as temperature and time of sonication. DCF degradation followed the pseudo-first-order kinetics model under different conditions. Results showed that photogenerated electrons on the catalyst surface played an important role in the mechanism of photocatalytic degradation of DCF. It also confirmed that in the presence of oxygen, the formation of oxidative species such as singlet oxygen and superoxide radical had major roles in the degradation of DCF.

Photocatalytic method was used as an efficient and simple way for degradation of trin-butyl phosphate (TBP). In contrast to other methods, in this method the mineralization occurs and no twin pollution is generated. Nd Doped TiO2 was synthesized via sol gel process and characterized by XRD and TEM tecniuqes. Then it was used as photocatalyst for TBP degradetion. It was found that the solution pH has important effect on degradation efficiency and kinetic. Degradation was more efficient in both acidic and alkali media. The kinetic studies indicated that the second order model at neutral pHs range was the dominant while in acidic or alkali conditions the kinetic models were first and third order respectively. By proceeding the degradation process, some products and byproducts are generated, which lead to the change of the solution pH and change of degradetion mechanism and kinetic. The LC MS was used to detect the intermediate and final products. Results showed that the method has high efficiency and is a promising procedure for decomposition of TBP.

Although several studies concerning the preparation of nitrogen Doped titanium dioxide visible-light active photocatalyst have already been reported, the effects of dopant concentration and calcination temperature have been rarely investigated. This paper focuses on the preparation of nitrogen Doped titanium dioxide (N-Doped TiO2) under different calcination temperature and nitrogen dopant concentration synthesizes by sol-gel method. The physicochemical characteristics of the prepared samples were examined using X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), Brunauer Emmett Teller (BET) analyzer, and UV-Vis spectrometer. Methylene blue was used in this study as a test chemical. The results demonstrated that the sample prepared under calcination temperature of 600oC show 8.33 and 5.57 % of rutile TiO2 phase depends on the dopant concentration. Furthermore, the sample prepared at a lower calcination temperature of 400oC and nitrogen to titanium (N/Ti) molar ratio of 2 and 6 exhibited larger specific surface area of 80.18 and 77.07 m2g-1, respectively. The photoactivity of the catalyst was also investigated on methylene blue decolorization using the different N-Doped TiO2 sample. The experiments demonstrated that the sample prepared at higher N/Ti molar ratio (6) and lower calcination temperature (400oC) demonstrates about 80 % efficiency under visible light. It was concluded that the higher photoactivity of the N-Doped sample prepared at higher dopant concentration and lower calcination temperature is due to synergistic effects of higher surface area, smaller crystal size and higher nitrogen content in the crystal lattice of TiO2.