Air Purification and the Photocatalytic Effect of Titanium Dioxide Titanium dioxide (TiO2) stands out in air purification technologies due to its photolytical properties. In the presence of ultraviolet (UV) light, TiO2 initiates a photocatalytic reaction generating free radicals. These radicals mineralize various pollutants present in the air, such as harmful organic compounds, microbial pathogens, and viruses, converting them into carbon dioxide (CO2) and water (H2O). This process occurs through the oxidation of atmospheric contaminants, effectively improving indoor and outdoor air quality. The application of photocatalytic air purification systems offers significant advantages, especially in reducing concentrations of volatile organic compounds (VOCs), diminishing bacterial and viral loads, and enhancing overall air quality in enclosed spaces. According to an article (Mamaghani et. al), they investigated that adjusting the properties of photocatalyst to increase the photoactivity and use of activated carbon fiber to enhance the adsorption of VOCs. The first objective was achieved by applying a calcination stage to the hydrothermallyprepared titania to increase its crystallinity without significant surface area and porosity loss. The characterization results revealed that by raising the calcination temperature, crystallinity, crystal size, and charge separation efficiency steadily improved while the surface area, porosity, and surface OH density diminished. Combination of titanium dioxide and activated carbon filter exhibited better efficiency compared to TiO2 coated on nickel foam filter as well as superior durability with respect to uncoated activated carbon fiber. Titanium Dioxide in Water Purification Technologies Titanium dioxide also exhibits its unique photocatalytic properties in water purification applications. Activated under sunlight or UV light, the surface of TiO2 exerts an oxidative effect on dissolved harmful chemical pollutants, microorganisms, and even heavy metals in water. This oxidative effect disrupts the molecular structure of the pollutants, breaking them down into simpler and harmless components. For instance, through TiO2 photocatalysis, organic pollutants are mineralized into CO2 and H2O, while heavy metal ions are reduced to more stable and harmless forms. This technique can be combined with other water treatment methods such as adsorption and filtration, thereby enhancing the efficiency and effectiveness of water purification systems. TiO2-based water treatment systems, particularly in wastewater treatment and drinking water provision, offer high energy efficiency and low operational costs in regions with abundant sunlight, contributing to environmental sustainability. According to an article (Gocer et. al), they achieved an efficiency of 80% in COD removal using titanium dioxide. The study shows that nanoparticles matter can be effectively used for domestic wastewater treatment. TiO2 could be used as pretreatment for the treatment of domestic wastewater. References Mamaghani, A.H., Haghighat, F., Lee, C., Effect of titanium dioxide properties and support material on photocatalytic oxidation of indoor air pollutants, Building and Environment, vol 189, 107518, 2021 Göçer, S., Kozak, M., Ayranpınar, İ., Duyar, A., Köroğlu, E. O., Cırk, K., Applıcatıon of Tıtanıum Dıoxıde(TiO2) Nanopartıcle Materıals on Domestıc Wastewater: Removal of Pollutants, 25(4), 2022
