Fabrication of europium-nitrogen co-doped TiO2/Sepiolite nanocomposites and its improved photocatalytic activity in real wastewater treatment

In order to effectively eliminate dyestuff in aquatic environment under solar irradiation, the europium-nitrogen (Eu-N) co-doped TiO2/Sepiolite nanocomposites were successfully fabricated via microwave-hydrothermal method. The effects of Eu and N contents on the chemical properties and crystal structure of the obtained nanocomposites were characterized. It was found that the carrier sepiolite was uniformly covered by doped-TiO2 nanoparticles and the doped Eu is beneficial for the growth of anatase crystallite. Furthermore, doped N extended the absorption to the visible region, and the doped Eu-III increased the adsorption ability further. The visible-light photocatalytic activities of the samples were evaluated for degradation of orange G. The results showed that the co-doped sample presented enhanced photocatalytic activity compared to undoped and monodoped samples. The increase in degradation efficiency can be ascribed to the synergistic effects of Eu and N co-doping. Among all samples, the optimum Eu-III doped content was 0.6% for the co-doped sample. The co-doped sample can also effectively treat real textile dye wastewater with over 70% COD removal efficiency in 3 h of irradiation time. This research demonstrates the co-doped TiO2/Sepiolite nanocomposites have a prospective application in textile dye wastewater treatment.