Application of photocatalytic paint for destruction of benzo[a]pyrene. Impact of air humidity

Abstract Latex (LX) paint was tested for photocatalytic decomposition of benzo[a]pyrene (BaP) under different conditions of relative humidity (RH), temperature and irradiation. Porcelain trays coated with LX paint were loaded with BaP solution, which was dissolved in acetonitrile. Trays were placed inside the photoreactor and irradiated with UV or a fluorescent lamp. Different conditions of RH and temperature inside the photoreactor were used. BaP preliminarily adsorbed on LX paint surface was decomposed faster at higher temperature and lower RH. For example, at 42 °C and RH 20 % BaP decomposition rate reached 64 %. At same temperature and with RH of 80 % this rate decreased to only 42 %. It was also demonstrated that at high RH (80 %) and under UV irradiation water contact angle on the paint surface was decreasing at a lower rate than under RH of 20 %. It was also proven that BaP could be sufficiently decomposed under irradiation by fluorescent lamp (59 % in comparison to 64 % under same environmental conditions with use of UV light). However, its decomposition rate was approximately 5 times slower than under UV light