Evaluation of the O3/graphene-based materials catalytic process: pH effect and iopromide removal

Abstract Graphene-based materials, including graphene oxide (GO), reduced-graphene oxide (rGO), and non-oxidative graphene (nOG) were evaluated for catalytic ozonation in water solutions. Among the graphene-based materials evaluated for catalytic ozonation, it was confirmed that rGO was unsuitable to apply to the ozone (O 3 )/graphene-based materials catalytic process because the high electron mobility of rGO prevented the transformation of O 3 into hydroxyl radicals ( OH). On the other hand, GO, which had sufficient oxygenated functional groups on the surface, decomposed and generated the most amount of O 3 and OH, respectively. Although O 3 /nOG process produced a lower amount of OH than O 3 /GO process, nOG was more effective than GO for the transformation yields of O 3 into OH. Furthermore, nOG could generate OH not only in the bulk phase, but also on the surface of nOG during catalytic ozonation. However, iopromide (IPM) was effectively removed during O 3 /GO process due to the more OH generated in the bulk phase than O 3 /nOG process.