A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection

Abstract

Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

Insight into the catalyst/photocatalyst microstructure presenting the same composition but leading to a variance in bacterial reduction under indoor visible light

“…This means a low number of catalytic points able to transfer charge to E. coli. The increase in roughness favoring the attachment of bacteria to several surfaces has been reported, but this observation cannot be extrapolated to surfaces directed towards the oxidation of pollutants [1,28].…”

“…No bacterial inactivation was found. Cu-ions reveal efficient antimicrobial activity degrading membrane/LPS layers [1,14,17,18,23,56]. Espirito-Santo [21,22] and Lemire et al [57] have recently reported bacterial inactivation on Cu surfaces.…”

“…The search of innovative antibacterial materials/surfaces able to inactivate bacteria/pathogens within very short times presenting high stability, adhesion and long-operational lifetime has gained in attention during the last decade due to the increase in the number of pathogenic infections leading to serious illness and death [1][2][3][4][5]. Biofilms spreading bacteria in hospitals, schools, public places are the most common and dangerous form of infection by bacteria, fungi and viruses.…”

Grafted semiconductors on PE-films leading to bacterial inactivation: Synthesis, characterization and mechanism

“…The mechanism of FeOx charge photo-generation will not be described in this study since it has been recently reported in our laboratory [16]. Also the TiO 2 -PE mediated bacterial inactivation has been reported widely in the open literature [1][2][3]18]. Below Eqs.…”

“…Bacterial inactivation materials/films have widely used TiO 2 and Fe-oxides under sunlight irradiation leading to highly oxidative radicals [1][2][3][4][5][6][7]. TiO 2 absorbs only 4-5% of the incident solar radiation with an absorption edge at ∼390 nm.…”