Solar water sterilization enabled by photothermal nanomaterials

Pathogen ingestion through drinking water bring about severe health threats to human beings. Recently innovative nanotechnology and their integrated systems provide new opportunities to address the challenges of solar water sterilization by killing pathogens. Of particular interest in this context, we aim to review the-state-of-art knowledge on solar water sterilization by use of photothermal nanomaterials to enhance the efficiency and affordability of water treatment. The basic principle of solar water sterilization is firstly described from the photothermal conversion and heat transfer physics to thermal sterilization mechanism. The engineering design of photothermal materials is then summarized from the aspects of light absorption, heat localization and other synergistic sterilization actions. The links between the photothermal properties of materials and their sterilization performance are highlighted by using solar energy. Furthermore, rationally orienting photothermal nanomaterials in reactor configurations including batch or continuous flow reactor and its crucial role in improving sterilization performance is analyzed depending on the reaction mechanism. Finally, the future challenges and prospects are outlined for further development of solar sterilization technology.