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Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon
Kan, E. AND S. G. HULING. Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. John Wiley & Sons, Ltd., Indianapolis, IN, 43(5):1493-1499, (2009).
To submit information for publication in Journal - Environmental Science Technology.
Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the pH point of zero charge. Consequently, a reduction in repulsive forces between Fe cations in solution and positively charged GAC surfaces resulted in greater penetration of Fe in GAC. MTBE removal in GAC and H2O2 reaction was proportional with temperature. Enhanced MTBE removal was measured under the acid-treated, Fe-amended conditions where Fe was distributed more uniformly. This condition led to a larger volume of the GAC where Fe, MTBE, and H2O2 co-existed and MTBE oxidation was favorable. H2O2 diffusive transport into the GAC particle was limited due to fast reaction. H2O2 penetration was inversely proportional with temperature and tortuosity and was faster over a larger relative volume of small GAC particles. Both intraparticle diffusive transport of MTBE into the "reactive zone" and fast reaction of H2O2 (i.e., short persistence) were limiting factors in MTBE removal from GAC. Conditions for optimal Fenton-driven regeneration of MTBE-spent GAC includes acid-treatment of small, Fe-amended GAC particles at elevated temperature.