Synergistic effect of MoO3/TiO2 towards discrete and simultaneous photocatalytic degradation of E. coli and methylene blue in water

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.