Nanoparticles for water disinfection by photocatalysis : a review

Photocatalysis is an efficient and ecological method of water and wastewater disinfection. During the process, various microorganisms are deactivated, including Gram-positive and Gram-negative bacteria, for example Escherichia coli, Staphylococcus aureus, Streptococcus pneumonia, and so on, fungi like Aspergillus niger, Fusarium graminearum, algea (Tetraselmis suecica, Amphidinium carterae, and so on) and viruses. Titanium dioxide (TiO2) is the most commonly used material due to its price and high oxidation efficiency; it is easy to modify using both physical and chemical methods, what allows for its wide use in industrial scale. Intensive research on novel photocatalysts (e.g. ZnO and carbon based photocatalysis like graphene, carbon nanotube, carbon nitride and others) has been carried out. The future development of nano-disinfection containing metal/metal oxides and carbon based nanoparticles should focus on: improving disinfection efficiency through different manufacturing strategies, proper clarification and understanding of the role and mechanism of interaction of the nano-material with the microorganisms, progress in scaling up the production of commercial nano-photocatalysts, determination of the extent of environmental release of nano-photocatalysts and their toxicity.