The photocatalytic degradation of isothiazolin-3-ones has been studied using the catalytically active TiO2 and ZnO and the inactive paint grade TiO2, under various illumination and chemical conditions. The reaction follows a pseudo-first-order kinetics. Three types of lamps have been used. The photocatalytic degradation is faster under UV lamp, when it is compared to reaction under suntest and fluorescent lamps. In the presence of oxygen and H2O2, the reaction proceeds faster than in air atmosphere. ZnO exhibits comparable activity with TiO2 and in some cases it was found to be even better than TiO2. The reaction was studied in aqueous suspensions as well as on gas–solid interfaces. The degradation of isothiazolin-3-ones in paint formulations was also studied.

Photocatalytic degradation of isothiazolin-3-ones in water and emulsion paints containing nanocrystalline TiO2 and ZnO catalysts

TiO2 sol was produced by the sol-gel method through the hydrolysis and the aging of tetrabutyl titanate and the TiO2 film was obtained by dipping and uniform lifting of the acid-treated and ultrasound-treated clean glass slides into the TiO2 sol followed by aging, drying, and calcination. The effect of the hydrolysis control agents to the formed sol was researched and the crystalline state, the morphology, and the photocatalytic properties of the products after calcination were characterized. The structural morphology, the contact angles before and after illumination, and the self-cleaning properties of the TiO2 film were characterized as well. The results showed that by using acetylacetone as the hydrolysis control agent, the formed TiO2 sol had relatively high stability. The product after the calcination of the TiO2 sol was of single anatase type with crystalline size of 18–20 nm and it could degrade nearly 100% of methylene blue after 90 min illumination. The formed TiO2 film is compact, continuous, smooth, and had the properties of super-hydrophilicity (after 30 min illumination due to its contact angle decreasing from 21° to nearly 0°) and anti-fogging capability, which indicated its excellent self-cleaning property.

The Preparation of TiO2 Film by the Sol-Gel Method and Evaluation of Its Self-Cleaning Property

Mechanism of photoelectrocatalytic dehydrogenation of 2-propanol on a polycrystalline ZnO photoelectrode

Interest in heterogeneous photocatalysis has heightened in the past 40 years, underscoring several perspectives and advances. A collection of applications including solar to fuel cells, intelligent ink and remote photocatalysis have been closely examined. As an emerging panacea for the treatment of recalcitrant pollutants, heterogeneous photocatalytic degradation has been highlighted with specific reference to synthetic aliphatic and aromatic organic substances. What’s more, various treatment technologies for integration with photocatalytic degradation have been outlined.

J.C. Kuriacose

Papers

Mechanism of photoelectrocatalytic dehydrogenation of 2-propanol on a polycrystalline ZnO photoelectrode

Photoelectrocatalytic reactions of 2-propanol and formamide on polycrystalline zinc oxide and tungsten trioxide electrodes

Photoelectrochemical reactions of sodium propionate over polycrystaline ZnO