Co₃O₄/CuO@C catalyst based on cobalt-doped HKUST-1 as an efficient peroxymonosulfate activator for pendimethalin...

Pendimethalin (PM) is an organic pollutant (herbicide), and systematic studies on PM degradation are scarce. The efficient degradation of PM in water remains a challenge that requires to be addressed. Herein, for the first time, elemental Co was doped into HKUST-1 using a solvothermal method to generate Co₃O₄/CuO@C via pyrolysis. The as-prepared catalyst was used to activate peroxymonosulfate (PMS) for PM degradation, obtaining a PM degradation efficiency of 98.2 % after 30 min. The assessment of the effects of various factors on the degradation efficiency revealed that ¹O₂ dominated PM degradation, whereas the contribution of SO₄•^- was negligible. Although 3Co₃O₄/CuO@C exhibited a good degradation performance against other organic pollutants, its degradation performance in real water was poor. The carbon layer reduced metal-ion leaching (Co and Cu), and the synergistic interactions between Co₃O₄ and CuO promoted PMS activation. The roles of the components of 3Co₃O₄/CuO@C in PM degradation by activated PMS were investigated in the presence of Co^IV and Co-OOSO₃^-. Two possible PM degradation pathways were systematically proposed, and the toxicity of the intermediates was analyzed. Finally, a mechanism for PM degradation by 3Co₃O₄/CuO@C-activated PMS was proposed.