Fenton-driven chemical regeneration of MTBE-spent GAC.
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 FeSO4 x 7H2O (3 g/L) (pH 2.5), were recirculated through the GAC column (30% bed expansion). The regeneration efficiency after two full cycles of treatment was calculated to be 91%. The cost of H2O2 was 0.59 dollars/kg GAC (0.27 dollars/lb) per regeneration cycle. There was no loss of sorptive capacity. Small reductions in carbon surface area and pore volume were measured. The lack of carbon deterioration under aggressive oxidative conditions was attributed to the oxidation of the target contaminants relative to the oxidation of carbon surfaces. The reaction byproducts from MTBE oxidation, tertiary butanol and acetone, were also degraded and did not accumulate significantly on the GAC. Excessive accumulation of Fe on the GAC and consequent interference with MTBE sorption and carbon regeneration was controlled by monitoring and adjusting Fe in the oxidative solution.
Huling
Scott G
SG
US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, P.O. Box 1198, Ada, OK 74820, USA. huling.scott@epa.gov
Jones
Patrick K
PK
Ela
Wendell P
WP
Arnold
Robert G
RG
D000096:Acetone / Q000032:analysis; D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000032:analysis / Q000737:chemistry*; D008738:Methyl Ethers / Q000737:chemistry / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D016062:Porosity; D018508:Water Purification / Q000379:methods*; D014881:Water Supply; D020002:tert-Butyl Alcohol / Q000032:analysis
C045076:Fenton's reagent; D005296:Ferrous Compounds; D008738:Methyl Ethers; D000096:Acetone; C043243:methyl tert-butyl ether; C020748:ferrous sulfate; D002244:Carbon; D006861:Hydrogen Peroxide; D007501:Iron; D020002:tert-Butyl Alcohol