ZIF-67/natural coal gangue composite as hydrogen peroxide activator for tetracycline hydrochloride degradation in water

The advanced oxidation process based on hydrogen peroxide (H2O2) can effectively degrade tetracycline hydrochloride (TC). The key to activating H2O2 for the degradation of organic pollutants lies in the exploration of efficient and cost-effective catalysts. Natural coal gangue (CG), a byproduct of coal mining, holds potential for use in catalytic oxidation of pollutants. Zeolitic imidazolate framework-67 (ZIF-67) is commonly employed to activate sulfate systems, serving as a highly efficient Co-based heterogeneous catalyst that promotes the generation of strong oxidation species. However, there has been no relevant research on using CG to load ZIF-67 for the activation of H2O2 in pollutant degradation. In this study, ZIF-67/CG catalysts were prepared, with ZIF-67 and CG serving as precursors for the highly efficient activation of H2O2. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) confirmed that ZIF-67/CG possesses a favorable ability to activate H2O2. The results revealed that the degradation efficiency of TC in the ZIF-67/CG/H2O2 system reached 82.8% within 60 minutes. Radical quenching experiments, electron paramagnetic resonance (EPR) analysis, and an analysis of the degradation mechanism identified that ·OH and 1O2 played major roles in TC degradation. Keywords: Hydrogen peroxide activation, Natural coal gangue, Tetracycline hydrochloride, ZIF-67