Photocatalytic degradation of tetracycline antibiotics using hydrothermally synthesized two-dimensional molybdenum disulfide/titanium dioxide composites

Tetracycline (TC) is a persistent antibiotic used in many countries, including China, India, and the United States of America (USA), because of its low price and effectiveness in enhancing livestock production. However, such antibiotics can have toxic effects on living organisms via complexation with metals, and their accumulation leading to teratogenicity and carcinogenicity. In this study, two-dimensional molybdenum disulfide/titanium dioxide (MoS2/TiO2) composites with different amounts of molybdenum disulfide (MoS2) were prepared via a simple, cost-effective, and pollution-free hydrothermal route. The synthesized MoS2/TiO2 microstructures were thoroughly characterized and their performance for the photocatalytic degradation of antibiotics such as TC was investigated. In the degradation experiments, the photocatalytic activities of TiO2 and the MoS2/TiO2 composites were compared, and the effects of different parameters, such as catalyst dose and electrolyte solution pH, were investigated. Under irradiation, the MoS2/TiO2 composites possessed superior photodegradation activity toward TC because of their excellent adsorption abilities, suitable band positions, and large surface areas as well as the effective charge-transfer ability of MoS2. Kinetics studies revealed that the photocatalytic degradation process followed pseudo-first-order reaction kinetics. In addition, a degradation mechanism for TC was proposed.