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

Abstract

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.