Enhancing mediated electron transfer in for efficient chloramphenicol degradation through Cu-modified Co@C catalyst

The degradation of organic pollutants in wastewater, such as the veterinary antibiotic chloramphenicol (CAP), is commonly achieved by increasing the concentration of reactive oxygen species (ROS). However, the contribution of the mediated electron transfer pathway is often overlooked. To address this, a carbon-coated CuCo bimetallic catalyst (CuCo@C) is synthesized by adding Cu into Co@C to activate peroxymonosulfate (PMS) for efficient degradation of CAP. The CuCo@C/PMS system exhibits high degradation activity, relying on the presence of ROS pathway and the enhanced mediated electron transfer pathway. The latter is facilitated by the excellent electron transport ability of the Cu-added Co@C catalyst, which accepts electrons from the CAP to form the active CuCo@C/PMS* complex, allowing further decomposition of CAP. The strong synergy between these two pathways results in a rate constant of first-order reactions (Robs) of 0.124 min -1, which is 2.2 and 22.9 times higher than those achieved by the single metal systems of Co@C/PMS and Cu@C/PMS, respectively. Intermediate products and toxicity analysis reveal that the toxicity of the CuCo@C/PMS system for the degradation of CAP is substantially reduced. Overall, this work offers a novel perspective on the efficient activation of PMS through enhancing mediated electron transport pathway.