Iron Optimization for Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon Abstract Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was accomplished through the addition of iron and hydrogen peroxide (H202) (15.9 grams per liter; pH 3). The iron concentration in GAC was incrementally varied (1,020-25,660 milligrams per kilogram [mg/kg]) by the addition of increasing concentrations of iron solution (ferrous sulfate hepta hydrate [FeS04.7H20]). MTBE degradation in iron- amended GAC increased by an order of magnitude over iron-unamended GAC, and H202 reaction was predominantly (99 percent) attributed to GAC-bound iron within the porous structure of the GAC. Imaging and microanalysis of GAC particles indicated limited penetration of iron into GAC. The optimal iron concentration was 6,710 mg/kg (1,020 mg/kg background; 5,690 mg/kg amended iron), and resulted in the greatest MTBE removal and maximum iron loading oxidation efficiency (MTBE oxidized |micrograms]/iron loaded to GAC [mg/kg]). At lower iron concentrations, the H202 reaction was iron-limited. At higher iron concentrations, the H202 reaction was not entirely iron-limited, and reductions in GAC surface area, GAC pore volume, MTBE adsorption, and iron- loading oxidation efficiency were measured. Results are consistent with non-uniform distribution of iron, pore blockage in H202 transport, unavailable iron, and limitations in H202 diffusive transport. The results emphasize the importance of optimal iron loading. Products Huling, S.G., K.P Jones, and T. Lee. (2007). "Iron Optimization for Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon." Environmental Science cmd Technology>, 41, 11: 4090-4096. Fe Amended to GAC, (FeW (m^g) Iron optimization in granular activated carbon The National Risk Management Research Laboratory's mission is to advance scientific and engineering solutions that enable EPA and others to effectively manage current and future environmental risks. NRMRL possesses unique strengths and capabilities and is dedicated to providing credible technological information and scientific solutions that support national priorities and protect human health and the environment. ------- |