In-situ production and activation of H 2 O 2 over hydroxyapatite modified CuFeO 2 for self-sufficient heterogeneous photo-Fenton degradation of doxycycline hydrochloride.

The self-sufficient heterogeneous photo-Fenton (SH-PF) system was constructed for doxycycline hydrochloride (DOH) degradation with hydroxyapatite (Hap) modified CuFeO ₂ (Hap/CuFeO ₂ ) composites through H ₂ O ₂ in-situ production. The modification of Hap could improve the specific surface area, visible-light response, light conversion efficiency, photoelectron lifetime and oxygen vacancies (OVs) of CuFeO ₂ , which was conducive to H ₂ O ₂ production and DOH degradation in SH-PF system. Notably, Hap/CuFeO ₂ fabricated with 0.5 g Hap (Hap/CuFeO ₂ -0.5) displayed more superior performance for DOH degradation compared to other synthesized catalysts. The Hap/CuFeO ₂ -0.5 load and initial solution pH for DOH degradation in SH-PF system were optimized, and the Hap/CuFeO ₂ -0.5 had good reusability and stability. The ^• OH was the main active species for DOH degradation, and the facilitation effect of ^• O ₂ ^- and photoelectrons on DOH degradation was associated with the H ₂ O ₂ production in the present work. In addition, the capture of photogenerated holes suppressed the recombination of photogenerated carriers, elevating the production of photoelectrons and thereby enhancing H ₂ O ₂ production and DOH degradation. The degradation pathways for DOH were proposed and the comprehensive toxicities of DOH were relieved after degradation in SH-PF system.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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