An easy and cheap procedure to immobilize TiO2 on glass surfaces using TiO2/SiO2 nanocomposite: Characterization and performance for the degradation of micropollutants of emerging concern in aqueous solutions

A simple high area TiO2/SiO2 nanocomposite was synthesized, characterized, and used to support P25 TiO2 on glass surfaces leading to an ease and cheap way to promote adhesion without refined pre-treatment steps. Photocatalytic performance and stability of the immobilized TiO2 was evaluated in laboratorial and pilot scales, under artificial and solar lights. Degradation rates of 80% and 45% were obtained for salicylic acid (16 mg L-1) and 17β-estradiol (E2, 1.0 mg L-1), respectively, after 4 h using a lab-made annular reactor. Solar batch experiments show a degradation rate of 85% for E2 (10 µg L-1) after 90 min. Photodegradation of trimethoprim (TMP, 500 ng L-1) and levofloxacin (LEVO, 1.0 mg L-1) using a compound parabolic concentrator (CPC) solar reactor revealed removal rates of 50% (once-through experiment) and 95% (batch experiment), respectively. CPC experiments show that the coated composite presents high physical stability after innumerous reuse cycles (more than 2000) under vigorous flow in continuous and batch operation. Overall, results evidenced the efficacy of the TiO2/SiO2 composite coated with P25 TiO2 on the degradation of micropollutants of emerging concern with low energetic costs.