Facile synthesis of CdS/TiO2 nanocomposite and their catalytic activity for ofloxacin degradation under visible illumination

Abstract

In this paper, CdS/TiO2 nanoparticles were hydrothermally synthesized and characterized in detail to understand its crystalline, structural, morphological, thermal and optical properties using various spectroscopic and analytical techniques. The characterization results confirmed that the prepared nanoparticles exhibited high purity, crystallinity and excellent optical properties. The photocatalytic activity of as-synthesized CdS/TiO2 nanoparticles was evaluated for the degradation of ofloxacin under visible light irradiation. The CdS/TiO2 nanoparticles exhibited superior photocatalytic activity, and about 86% of ofloxacin was degraded in 180 min of visible illumination which was higher than bare TiO2. The enhanced photocatalytic activity of nanocomposite was attributed to the availability of more active sites for the drug molecules and effective response in visible region. Active species trapping experiments and photoluminescence terephthalic acid technique confirmed that hydroxyl radicals (OH) are the prominent group for the photodegradation of fluoroquinolone drug, ofloxacin. Based on the scavenger study, photodegradation mechanism was proposed. Further, the CdS/TiO2 was used as a photocatalyst for simulated hospital wastewater and about 48.5% TOC reduction was observed with CdS/TiO2 (0.45 g/L) in 270 min under visible light.