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 (photo-Fenton) 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.