A Floatable and Highly Water-Durable TiO2-Coated Net for Photocatalytic Antibacterial Water Treatment in Developing Countries

Abstract

A TiO2-coated net with photocatalytic antibacterial properties that purifies water for practical use in developing countries was fabricated. The TiO2 particles were modified with a silane coupling agent, aminopropyltriethoxysilane or hexadecyltrimethoxysilane, to improve particle dispersibility. The net comprises three layers: a TiO2-silicone photocatalyst layer, a silicone layer to protect the net substrate from the oxidizing power of TiO2, and a polypropylene net substrate. The net is flexible and light enough to float on the surface of water. By modifying the surface of the TiO2 particles, we succeeded in preparing a highly water-durable photocatalyst coating that can be maintained for 49 days of outdoor exposure. The inactivation of E. coli by the TiO2-coated net under 1.0 mW/cm2 of UV irradiation was confirmed. Furthermore, the antibacterial properties were investigated under natural sunlight. The number of E. coli decreased from 320,000 to 10 CFU/mL under natural sunlight in just 2 h. The results showed that the photocatalyst-coated polypropylene net effectively eliminates E. coli from water, reducing the risk of infectious diseases.