Comparison of the functional properties of ilite clay/ TiO2 and kaolinite clay/TiO2 coatings

Ilite/ TiO2 and kaolinite/TiO2 coatings, impregnated with 10 wt.% nano TiO2 using mild conditions, was applied to and investigated on three types of substrates: porous (clay roofing tiles), highly porous (clay-fly ash composite), and non-porous (window glass). The coatings were analyzed for their capillary water absorption and surface properties, including roughness, micro-hardness, and hydrophilicity. The functional properties of self-cleaning and photocatalytic activity were evaluated by measuring the initial contact angle and the photodegradation of the model pollutant Rhodamine B, which was assessed during UV/VIS irradiation. The study suggests that the applied synthesis by mechanical activation methodology resulted in a homogenous distribution of TiO2 as an active component in the photocatalytic coating, leading to better surface and functional properties. Novel natural clay/TiO2-based coatings are advantageous due to their low cost and simple preparation, ensuring high photo-degradation efficiency.