Research PaperHighly efficient g-C3N4/TiO2/kaolinite composite with novel three-dimensional structure and enhanced visible light responding ability towards ciprofloxacin and S. aureus

- Novel 3D heterogeneous g-C3N4/TiO2/kaolinite was synthesized.
- High efficiency was obtained through the construction of “sandwich” structure.
- Both water-contained antibiotic and waterborne bacteria were degraded.
- Mechanisms for enhanced activity of composite were investigated.

A novel 3D heterogeneous g-C3N4/TiO2/kaolinite composite with enhanced visible light activity was fabricated via a mild sol-gel method associated with chemical stripping and self-assembly. Compared with bare photocatalysts, the g-C3N4/TiO2/kaolinite 3D structure exhibits enhanced adsorption-photocatalytic degradation ability for the removal of ciprofloxacin (CIP) under visible-light irradiation, and also facilitate the recyclability of the photocatalyst as demonstrated from the reusability test. The apparent rate constant of the composite is up to around 5.35 times, 6.35 times and 4.49 times that of bare TiO2, g-C3N4 and P25, respectively, and a possible degradation pathway was also proposed. On the other hand, the as-received composite also exhibited enriched disinfection ability towards S. aureus. It is indicated that the superoxide radical (O2−) is the main active species in the degradation process, and the superior photocatalytic performance of composite should be mainly attributed to both the improvement of light harvesting as well as the enhanced separation and transfer efficiency. It is expected that this novel ternary visible-light responding composite would be a promising candidate material for the organic pollutants degradation and bacteria inactivation.

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