Photocatalytic inactivation of Gram-positive Enterococcus sp. and Gram-negative E. coli by using a novel visible- light-driven TiO2 based composite

摘要

Nowadays, water pollution by pathogenic microorganisms has become a big problem. Unfortunately, all of the conventional water disinfection methods, including chlorination, ozonation and ultraviolet, have some disadvantages, such as high cost and formation of byproducts with potential carcinogenicity. Among the processes in development, semiconductor photocatalysis has emerged as a very attractive technology for water disinfection, due to its superior oxidation ability, nontoxicity and stability. However, most of the reported studies have only used one model bacteria group. Considering that some differences in photocatalytic inactivation response have been reported for different type of microorganisms, more efforts should be focused on the establishment of possible differences in the photocatalytic disinfection efficiency depending on the selected indicator microorganism. According to the previous studies, a novel P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst, firstly synthesized by our lab, has been demonstrated as a promising material with remarkable efficiency in decomposing the organic matter [1]. Hence, in this study, the photocatalytic inactivation of two different microorganisms, Gram-negative Escherichia coli (E. coli) and Gram-positive Enterococcus species (Enterococcus sp.), were comparably investigated by using P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst under LED light irradiation.