Activated Carbon Modifications for Heterogeneous Fenton-Like Catalysis.

The effective and efficient degradation of persistent, recalcitrant pollutants by advanced oxidation processes is vital to both reduce hazardous waste and remediate polluted waters. One such advanced oxidation process is the use of Fenton chemistry, which can be optimized using heterogeneous catalysts. However, to make this AOP viable over conventional treatment methods, the technology needs to be optimized from both a technical and economic standpoint. From a heterogeneous catalyst optimization perspective, varying the surface chemistry of activated carbon and impregnating or doping with Fenton-like catalytic nanomaterials removes precipitation complications associated with traditional iron species in Fenton chemistry while generating effective amounts of highly oxidative hydroxyl radicals. Utilizing various techniques to synthesize heterogeneous catalysts with activated carbon as a backbone, in the presence of H₂O₂ the formation of hydroxyl radicals and removal of benzoic acid is tested. Comparing various additives, raw activated carbon impregnated with 5% MnO₂ in the presence of H₂O₂ realized a high concentration of hydroxyl radical formation while maintaining low cost and relative ease of synthesis. This AC-Mn5 catalyst performed effectively in varying concentrations of H₂O₂, utilizing various synthesis techniques, after simulated aging of the catalyst structure, and over a wide pH range with the highest radical formation at acidic pH values. Utilizing this catalytic material as a substitute for iron species associated with traditional Fenton technology, the goal of designing a full set of oxidation functions towards persistent, recalcitrant pollutant removal while maintaining cost-effectiveness and scalability is proposed. It is anticipated these catalytic materials are effective to eliminate analogous contaminants and mixtures.