Photocatalytic degradation and inactivation of Escherichia coli by ZnO/ZnAl2O4 with heteronanostructures

ZnO/ZnAl2O4 nanocomposites with heteronanostructures were successfully prepared by co-precipitation method. The as-prepared samples were characterized by HRTEM, TEM, XRD, BET, TG-DTA, and UV-Vis spectra techniques. The photocatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of methyl orange and inactivation of Escherichia coli in suspension under the irradiation of the simulated sunlight. The effects of compositions, calcination temperatures, concentration of photocatalysts and light source on the photocatalytic activities were systematically studied. The results show that when the concentration of ZnO/ZnAl2O4 photocatalyst with the starting Zn to Al molar ratio of 1:1.5 calcined at 600 degrees C is 1.0 g/L, the maximum photocatalytic degradation rate of 98.5% can be obtained in 50 min under the irradiation of the simulated sunlight. Under the same conditions, an inactivation rate of 99.8% for E. coli is achieved in 60 min.