New Insights About the Role of Some Activated Carbon Materials in the H 2 O 2 -Involved Advanced Oxidation of Organic Contaminants

In this study, we investigated the degradation of tetracycline (TC), rhodamine B (RhB), and p-nitrophenol (PNP) in the activated carbon (AC)/H2O2 system using three AC materials prepared from coconut shell, glucose, and corn straw. Our findings indicate that, despite the significant decomposition of H2O2, the degradation of TC and RhB in the AC/H2O2 system was almost negligible. For PNP, a weak degradation was observed in the AC/H2O2 system, but the degradation rate was much slower than that obtained from the homogeneous Fenton oxidation (H2O2/Fe2+) system under the same amount of H2O2 consumption. Only weak electron spin resonance signals of DMPO-·OH and DMPO-·O2− were detected from the AC/H2O2 system. This suggested that H2O2 decomposition mainly followed a nonradical pathway in the system, consistent with the poor performance of organic degradation in spite of significant H2O2 decomposition. In summary, this study demonstrated that some AC materials may be not good Fenton-like catalysts, and while AC is sometime used as heterogeneous support of Fenton-like catalysts, the role of AC in the H2O2−invovled advanced oxidation should be critically examined, as it may not facilitate H2O2 utilization geared to organic contaminant degradation.