Facile preparation of Ti3+ self-doped TiO2 nanoparticles and their dramatic visible photocatalytic activity for the fast treatment of highly concentrated Cr(vi) effluent

In the present work, Ti3+ self-doped TiO2 nanoparticles were prepared in a simple one-pot solvothermal process. Meanwhile, the photocatalytic activity of the as-prepared TiO2 nanoparticles was explored under visible light irradiation for the treatment of effluent containing Cr(vi). Finally, the photocatalytic mechanism was discussed. The results show that the Ti3+ self-doped TiO2 nanoparticles obtained are an efficient visible photocatalyst for the reduction of Cr(vi). When the concentration of Cr(vi) is 10 mg L-1, about 95% of Cr(vi) can be removed within 1 min. More interestingly, the aforementioned TiO2 nanoparticles are a promising candidate with remarkable visible photocatalytic activity for the fast treatment of highly concentrated Cr(vi) effluent. When the concentration of Cr(vi) is 34 mg L-1, the reduction ratio of Cr(vi) is approximately 95% after 12 min of visible irradiation. Even if the concentration of Cr(vi) is very high (104 mg L-1), the reduction ratio of Cr(vi) is still up to 94% after 5 h of irradiation. Our work provides a new strategy for designing an efficient visible photocatalyst which is suitable for the rapid removal of highly concentrated Cr(vi) for environmental therapy.