The synthesis of nanostructure TiO2 co-doped with N and Fe and their application for micro-polluted source water treatment.

The doping of titanium dioxide (TiO2) with various metal or nonmetal elements has been considered as an effective strategy to extend the photoactive wavelength region to include visible light. In this paper, TiO2 nanoparticles co-doped with N and Fe were prepared via a sol-gel route, followed by a heat treatment at elevated temperatures. The co-doped TiO2 nanoparticles showed a strong visible light absorption and exhibited an enhanced photocatalytic activity for the degradation of methylene blue as compared with pure TiO2 nanoparticles. Polypropylene packings, coated with the prepared N-Fe co-doped TiO2 nanoparticles, were used as a heterogeneous catalyst for the treatment of micro-polluted source water. Under the illumination of sunlight, when the water was treated with the coated polypropylene packings, the reduction of COD(Mn) was about 60%, whereas it was just 10% and 30% when the water was treated with pure polypropylene packings and polypropylene packings coated with pure TiO2, respectively. The NH3-N could also be decreased dramatically on the co-doped TiO2-coated polypropylene packings. The results showed that N-Fe co-doped TiO2-coated polypropylene packings still had a strong activity after three months of operation.