Peroxymonosulfate activation of magnetic Co nanoparticles relative to an N-doped porous carbon under confinement: Boosting stability and performance

Abstract

The integration of metal nanoparticles into carbon materials has catch considerable attention. In this study, we have successfully fabricated the N-doped porous carbon encapsulated magnetic Co nanoparticles (Co@NC-800) through a two-step pyrosis of zeolitic imidazolate frameworks (ZIF-67). The obtained Co@NC-800 exhibited excellent stability in activating peroxymonosulfate (PMS) towards tetracycline (TC) degradation without obvious Co leaching and magnetically separable. The removal efficiency reached up to 90.1% within 3 min and 74.7% of total organic carbon (TOC) removal efficiency could be obtained in 30 min towards TC by Co@NC-800/PMS system. Mechanism explorations revealed the encapsulated Co nanoparticles in the porous N-doped carbon promoted the catalytic activity and stability. The two-pathway mechanism study indicated that radical and non-radical oxidations acted together in TC degradation. Moreover, some potential factors, including PMS dosage, TC concentration, solution pH value, anion/organic matters and temperature were investigated. The Co@NC-800/PMS system exhibited high efficiency in removal of various antibiotics (oxytetracycline, chlortetracycline and deoxytetracycline). Even in actual water bodies (tap water, river water and pharmaceutical wastewater), the Co@NC-800/PMS system displayed excellent performance. This study proposed a design of metal nanoparticles under confinement for fabricating highly active catalysts towards PMS activation.