Preparation, characterization, and photocatalytic performance of atmospheric plasma-sprayed TiO2/Al2O3 coatings on glass substrates

Abstract

Conventional methods for wastewater treatment are not always efficient in persistent organic pollutant degradation processes. Therefore, low-cost and effective methods of their removal from sewage are constantly sought. This study presents an attempt to fabricate thermally sprayed ceramic coatings on glass and their characterization. Granulation of TiO2, Al2O3, and their blends in different mass ratios was done. Assessment of actual density and specific surface area was performed, and TiO2, Al2O3, and TiO2/Al2O3 were then used as a coating material for the deposition on glass substrates in atmospheric plasma spraying. Surface analysis of coatings was done by evaluating their roughness and wettability. Both powder and coatings samples were characterized using the X-ray diffraction method and scanning electron microscopy. The photocatalytic activity was estimated in the Eosin Y degradation process under UV light. UV–Vis spectroscopy was applied to observe the changes in the dye concentration. Additional tests for color measurements before and after photodegradation were carried out using a sphere spectrophotometer in CIELab color space. Particle size distribution was examined for the powder samples after the granulation and d50 was stated at 48.42–63.28 µm. Characterization of coatings via roughness measurements showed the average roughness of a surface equal to 4.90–9.65 µm. Moreover, most of the coatings appeared to be hydrophobic with water contact angles between 100° and 130°. All of the coatings showed Eosin Y degradation ability and the highest efficiency was reached for 100T/C, A75T/C, and A50T/C samples and stated at 71%, 62%, and 51%, respectively. Graphical abstract