Ag@ZnO-saponite nanocomposite for ciprofloxacin photodegradation

The use of antibiotics has been growing and, consequently, their unregulated disposal has become a global concern for the pollution of water bodies. The development of technologies and materials to remove these contaminants is a relevant topic, so photocatalysis appears as an efficient method for removing these pollutants, termed emerging contaminants, mainly due to its ability to mineralize the target molecules. Clay minerals are used as supports for semiconductors in order to increase the photocatalytic activity in the degradation of various pollutants. In this sense, the objective of this research is to develop new photocatalysts by incorporating Ag and ZnO nanoparticles in synthetic saponite to be used in the photodegradation of the antibiotic ciprofloxacin in aqueous solution. The materials were synthesized by colloidal route. The results showed a good incorporation of nanoparticles on the support surface. The optical gap of the ZnO-saponite nanocomposite corresponds to 3.1 eV, whereas the Ag@ZnO-saponite nanocomposite (after deposition of Ag NPs) showed significant displacement variation in the band gap values, corresponding to 2.2 eV. This decrease justifies the photocatalytic activity in the visible region. The Ag@ZnO-saponite nanocomposite showed efficiency close to 90% of photodegradation of ciprofloxacin after 120 min of irradiation. Therefore, this material proves to be highly efficient for antibiotic degradation under visible light irradiation.