The use of carbon materials in persulfate-based advanced oxidation processes: A review

With their unique nanostructure, excellent conductivity, chemical stability and adsorption properties, carbon materials have a wide range of application possibilities in the field of catalysis, and are expected to become a new generation of green non-metallic catalysts. In recent years, worldwide research on the applications of various carbon materials in the advanced oxidation technology using activated persulfate (PS) has developed rapidly. Here, theoretical and applied research progress on graphene-based materials, carbon nanotubes, carbon fibers, porous carbons, carbon aerogels, carbon microspheres, carbon nanobubbles and carbon quantum dots as heterogeneous catalysts to activate peroxymonosulfate and peroxydisulfate are reviewed. The preparation methods and structural characteristics of the carbon catalysts, the relationship between their structure and activity in the activation of PS, the paths for the generation of free radicals and non-free radicals, and the uses of carbon materials in the degradation of pollutants by activated PS are summarized. Finally, the challenges of poor stability, environmental risks and high costs of carbon catalysts in practical applications and their solutions are pointed out, with the aim of providing references for the further applications of carbon materials in advanced oxidation technologies.