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Iron Optimization for Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon
journal contribution
posted on 2007-06-01, 00:00 authored by Scott G. Huling, Patrick K. Jones, Tony R. LeeFenton-driven chemical oxidation of methyl tert-butyl
ether (MTBE)-spent granular activated carbon (GAC) was
accomplished through the addition of iron (Fe) and
hydrogen peroxide (H2O2) (15.9 g/L; pH 3). The Fe concentration
in GAC was incrementally varied (1020−25 660 mg/kg) by
the addition of increasing concentrations of Fe solution (FeSO4·7H2O). MTBE degradation in Fe-amended GAC increased
by an order of magnitude over Fe-unamended GAC and H2O2
reaction was predominantly (99%) attributed to GAC-bound Fe within the porous structure of the GAC. Imaging
and microanalysis of GAC particles indicated limited
penetration of Fe into GAC. The optimal Fe concentration
was 6710 mg/kg (1020 mg/kg background; 5690 mg/kg amended
Fe) and resulted in the greatest MTBE removal and
maximum Fe loading oxidation efficiency (MTBE oxidized (μg)/Fe loaded to GAC(mg/Kg)). At lower Fe concentrations,
the H2O2 reaction was Fe limited. At higher Fe concentrations,
the H2O2 reaction was not entirely Fe limited, and reductions
in GAC surface area, GAC pore volume, MTBE adsorption,
and Fe loading oxidation efficiency were measured. Results
are consistent with nonuniform distribution of Fe, pore
blockage in H2O2 transport, unavailable Fe, and limitations
in H2O2 diffusive transport, and emphasize the importance
of optimal Fe loading.