Abstract:
Simultaneous photocatalytic Escherichia coli (E. coli) inactivation and methylene blue (MB) degradation in water are achieved by a composite containing MoO3 and TiO2 under UV and UV-visible irradiations. The MoO3/TiO2 composites are synthesized via an incipient wet impregnation method with varying concentrations of MoO3 from 0 to 10 wt% in TiO2. Under both UV and UV-visible irradiations, the photocatalytic results indicate that the MoO3/TiO2 composites destruct the bacteria significantly at higher rates than the unmodified TiO2 and pure MoO3. Particularly, 5 wt% MoO3/TiO2 sample exhibits improved photocatalytic activity for the simultaneous E. coli destruction and MB degradation under UV-visible irradiation, replacing TiO2 which is photoactive only under UV irradiation. The Bronsted acidity and OH radical concentration increase with MoO3 concentration on TiO2 along with a heterojunction effect are the responsible factors for yielding high photocatalytic activity of MoO3/TiO2 composite under UV-visible irradiation. Particularly, 99% of degradation of 20 ppm MB is achieved with a very low catalyst dose of 0.6 g l(-1) at a very less time of 20 min using 5% MoO3/TiO2 sample under UV-visible irradiation. Consequently, MoO3/TiO2 composite is a potential candidate for E. coli inactivation and MB degradation in water, signifying its prospective for the purification of water.