Solar water sterilization enabled by photothermal nanomaterials

Abstract

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. This work discusses physical understanding and engineering design of photothermal nanomaterials and reactors by use of solar energy for water sterilization. ● Photothermal mechanism and heat transfer physics are revisited. ● The basic principle of solar water sterilization is stressed. ● The engineering design of photothermal materials is fully summarized. ● Nanomaterials integrated in batch or continuous flow reactors are discussed. ● Future challenges and prospects are highlighted for further development.