Facile synthesis of nano CeO2/sepiolite composite as visible-light-driven photocatalyst for rapid tetracycline removal

A novel CeO2/sepiolite (CeO2/SEP) composite with sepiolite as the support of CeO2 was successfully prepared using a simple ammonia precipitation method for the photocatalytic degradation of tetracycline (TC) by loading CeO2 nanoparticles on sepiolite. The analytical results showed that CeO2/SEP had good crystallization, and CeO2 nanoparticles were deposited on the surface of fibrous sepiolite. The composite photocatalyst with 50% CeO2 loading presented the highest tetracycline degradation efficiency (92.7%), and the reaction rate constant was 4.88 times greater than that of pure CeO2. In addition, quenching experiments showed that the main reactive active species included photogenerated holes (h+) and superoxide radical anions(O2·-).Furthermore, the enhanced photodegradation mechanisms and the possible degradation pathways of TC were also systematically discussed. The investigating results show that the enhanced photocatalytic performance was mainly due to the uniform attachment of CeO2 with smaller particle size on the surface of sepiolite, which increased the specific surface area of the photocatalyst and promoted the redox cycle of Ce3+/Ce4+ to generate more reactive free radicals. It can be concluded that this study offers a new potential option for efficient photodegradation of antibiotics in wastewater based on the visible-light-driven mineral based photocatalyst.