CoO/CuO@C catalyst based on cobalt-doped HKUST-1 as an efficient peroxymonosulfate activator for pendimethalin degradation: Catalysis and mechanism.

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 CoO/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 O dominated PM degradation, whereas the contribution of SO• was negligible. Although 3CoO/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 CoO and CuO promoted PMS activation. The roles of the components of 3CoO/CuO@C in PM degradation by activated PMS were investigated in the presence of Co and Co-OOSO. Two possible PM degradation pathways were systematically proposed, and the toxicity of the intermediates was analyzed. Finally, a mechanism for PM degradation by 3CoO/CuO@C-activated PMS was proposed.