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FENTON-DRIVEN CHEMICAL REGENERATION OF MTBE-SPENT GAC
Citation:
Huling*, S G., P K. Jones*, W. P. Ela, AND R. G. Arnold. FENTON-DRIVEN CHEMICAL REGENERATION OF MTBE-SPENT GAC. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 39:2145-2153, (2005).
Description:
Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was chemically regenerated utilizing the Fenton mechanism. Two successive GAC regeneration cycles were performed involving iterative adsorption and oxidation processes: MTBE was adsorbed to the GAC, oxidized, re-adsorbed, oxidized, and finally re-adsorbed. Oxidant solutions comprised of hydrogen peroxide (H2O2) (1.7 - 2.0%) and iron (Fe) ( FeSO4@7H2O) were applied and recirculated (upflow) through the GAC column at a rate sufficient for 30% bed expansion. The cost of H2O2 was $0.3/lb GAC, and regeneration efficiency after two full cycles of treatment was estimated to be 92 or 100%, depending on the method used to estimate regeneration. Reaction byproducts from MTBE oxidation included tertiary butanol (TBA) and acetone. These byproducts were also degraded and did not significantly accumulate on the GAC or volatilize from the treatment system. Excessive accumulation of Fe on the GAC and potential interference in the regeneration process was controlled by monitoring and adjusting Fe in the oxidative solution. A 2% loss in surface area and negligible changes in the pore volume and pore volume distribution were measured as a result of oxidative treatment. Fe and H2O2, small in size relative to the target contaminants (MTBE, TBA, acetone), could likely penetrate far into the microporous structure, serving to effectively regenerate the activated carbon, as observed.