Heterostructure CoFe2O4/kaolinite composite for efficient degradation of tetracycline hydrochloride through synergetic photo-Fenton reaction

Compared with single photocatalytic reaction and single Fenton reaction, visible light assisted Fenton (photoFenton) reaction has higher degradation efficiency for environmental pollutants and great potential in the treatment of organic wastewater. Herein, a CoFe2O4/kaolinite (CFO/K) composite photocatalyst was synthesized by a simple sol-gel method, using kaolinite as a carrier. Such a composite was used to degrade tetracycline hydrochloride (TCH) through synergetic photo-Fenton reaction. Compared with pure CoFe2O4 (CFO), CFO/K containing 40 wt% of kaolinite (CFO/K-40%) had larger specific surface area, abundant surface active sites, and higher photogenic electron hole pairs separation efficiency. Hence, it exhibited a higher photocatalytic degradation efficiency than CFO, and the degradation efficiency was up to 84.82% within 30 min. After three cycles, the photocatalytic degradation efficiency could remain at 76.58%, exhibiting good catalyst stability. During the TCH degradation process, hydroxyl radical and superoxide radical were the dominant active species. In addition, the CFO/K-40% composite exhibited a good degradation performance for different organic pollutants. This study suggested that the CFO/K composite material, as an efficient photocatalyst, has promising applications in the field of kaolinite-based photocatalysts for the treatment of organic wastewater.