Photo-oxidation of nitrite anions in aqueous solution for the benchmarking of nano-TiO2 photocatalytic coatings

Photocatalytic coatings have potential as an air purifying technology for removal of pollutants such NOx gases, which are converted into and immobilized nitrate via photo-oxidation. This work is investigation the photocatalytic conversion nitrite in aqueous phase. The study this reaction important to understand mechanism through immobilization species nitrates takes place during conversion, especially humid environments. We investigate performance TiO2 nanoparticles (Aeroxide® P25) corresponding prepared using acrylic binder (TiO2 NP-acrylic) towards photo-conversion nitrite. combination a simple colorimetric method (Griess test) quantification UV–vis spectroscopy analysis shown be useful monitoring conversion. tests with suspended show that benefits from lower pH, higher temperature concentration photocatalyst. advantage pH attributed electrostatic attraction between adsorbed H3O+ NO2−, facilitates transport active surface. When photocatalyst coating factor primary significance pigment volume relative critical (λ), increases linearly λ range 0.6–1.2. creation more porous structure access light surface sites.