Octahedral zero-valent copper activated peracetic acid for efficient tetracycline hydrochloride degradation under neutral condition: Theoretical calculation and toxicity evaluation

With the enhancement of environmental awareness, the efficient and environmentally friendly catalyst activated peracetic acid (PAA) technology has been research focus of research in recent years. Herein, octahedral Cu/CN500 derived from nitrogen doped copper-based metal organic framework (N-Cu-MOF) was prepared by a calcination strategy, and was used as a heterogeneous catalyst for the PAA-activated degradation of tetracycline hydrochloride (TCH). The k value for TCH removal in the Cu/CN500/PAA system was three times higher than that in the N-Cu-MOF/PAA system, showing excellent PAA activation by Cu/CN500. The Cu²⁺/Cu⁺ redox cycle facilitated PAA activation, which generated reactive species such as HO•, CH₃C(O)O•, CH₃C(O)OO•, ¹O₂ and O₂^·-. Among these, CH₃C(O)OO• and ¹O₂ played a dominant role in facilitating the degradation of TCH. Furthermore, the effects of humic acid (HA), Cl⁻, and NO₃⁻ on the degradation of TCH were negligible in the Cu/CN500/PAA system. Based on density-functional theory (DFT) calculations and liquid chromatography-mass spectrometry (LC-MS) analyses, the degradation pathways of TCH were further elucidated. Moreover, the toxicity of TCH and its intermediate degradation products was evaluated using the four-season creamy cabbage experiments and the Toxicity Evaluation Software Tool. The results indicated that the biological toxicity of TCH diminishes as the degradation process progresses. Finally, the practical application of the material is explored. This study described the performance of an efficient and easily separable catalyst for PAA activation, which promoted the development and application of PAA-based AOPs in wastewater treatment.