Carbon-based magnetic nanocomposite as catalyst for persulfate activation: a critical review

The activation of persulfate to produce active radicals has been attracting wide attention in environmental remediation fields. Among various catalysts, non-metal carbocatalysts and carbon-based composites have shown attractive prospects given that they are environmental-friendly, highly efficient, abundant, and diverse. In this paper, the use of carbon-based magnetic nanocomposites as catalysts for persulfate activation was reviewed and discussed. The preparation methods of carbon-based magnetic nanocomposites were first briefly summarized. Subsequently, the use of activated carbon, carbon nanotubes, graphene oxide, biochar, and nanodiamond-based magnetic composites to activate persulfate was discussed, respectively. A synergetic effect between carbon materials and magnetic nanoparticles facilitated the activation process because of the increased electron transfer capacity, good dispersity of magnetic nanoparticles, and good repeatability and separability. Both radical and non-radical pathways were detected in the activation processes, but the specific mechanisms were greatly influenced by the components of the catalyst and solution conditions. And fundamental studies were needed to clarify the inner mechanisms of the process. In the end, strategies for enhancing the catalytic performances of carbon-based magnetic nanocomposites were suggested. It is expected that this review will provide some inspirations for developing highly efficient and green catalyst, as well as sulfate radical-based advanced oxidation technology for the remediation water environment.