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REPEATED REDUCTIVE AND OXIDATIVE TREATMENTS ON GRANULAR ACTIVATED CARBON
Huling*, S G., P K. Jones*, W. P. Ela, AND R. G. Arnold. REPEATED REDUCTIVE AND OXIDATIVE TREATMENTS ON GRANULAR ACTIVATED CARBON. February, ASCE (ed.), JOURNAL OF ENVIRONMENTAL ENGINEERING. American Society of Civil Engineers (ASCE), Reston, VA, 131(2):287-297, (2005).
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Fenton oxidation and Fenton oxidation preceded by reduction solutions were applied to granular activated carbon (GAC) to chemically regenerate the adsorbent. No adsorbate was present on the GAC so physicochemical effects from chemically aggressive regeneration of the carbon could be distinguished from the potential effects of accumulation of reaction byproducts. Fifteen sequential oxidation treatments with hydrogen peroxide (H2O2) and fifteen sequential reduction/oxidation treatments with hydroxylamine and H2O2 on Fe-amended GAC were evaluated. The Fe amended to the GAC was predominantly amorphous, poorly-ordered Fe. The GAC Iodine number, N2 BET surface area, microporosity, and total porosity declined with sequential treatments, but meso- and macroporosity essentially remained unchanged. An inverse relationship was established between the number of chemical treatments of the GAC and contaminant (methyl tert-butyl ether, 2-chlorophenol, trichloroethylene) adsorption capacity. The loss of Fe and GAC resulting from reduction/oxidation treatment was greater than from oxidation alone. However, similar changes in the Iodine number, N2 BET surface area, and pore volume distribution with either treatment suggest that the effects of treatment are functionally dependent on oxidation and independent of hydroxylamine reduction.