Core–shell CoN@Co ultra-stable nanoparticles on biochar for contamination remediation in water and soil

Abstract Nanomaterials have been extensively employed in various applications over the past several decades, however, the stability of functional nanoparticle catalysts (NPCs) for effective degradation of organic contaminants remains a significant challenge. Herein, we present a cost-effective biochar loaded uniformly dispersed ultra-stable Co nanoparticles with an average diameter of 8 nm as a highly efficient peroxymonosulfate (PMS) activation catalyst. The reactive radicals produced from the catalyst/PMS system are able to degrade several model organic pollutants of environmental and public health concerns, including trichlorobiphenyl, bisphenol A and diethyl phthalate, with less pH limitation and Co 2+ leaching. Mechanism investigation demonstrates that the CoN plays the key role in the catalyst stability and PMS activation via acid resistance and electron bridging effects, respectively. Meanwhile, the incorporation of nitrogen (N) and sulfur (S) atoms within the substrate is considered to bolster the adhesion strength between metal nanoparticles and the carbon matrix via strong metal-support interaction. The catalyst was further applied in practical treatment of water and soil polluted by organic pollutants, exhibiting a satisfactory degradation efficiency (> 90% in 60 min) for environmental applications.