MTBE Oxidation by Conventional Ozonation and the Combination Ozone/Hydrogen Peroxide:  Efficiency of the Processes and Bromate Formation

Abstract

The present study investigates the oxidation of methyl tert-butyl ether (MTBE) by conventional ozonation and the advanced oxidation process (AOP) ozone/hydrogen peroxide under drinking water treatment conditions. The major degradation products identified were tert-butyl formate (TBF), tert-butyl alcohol (TBA), 2-methoxy-2-methyl propionaldehyde (MMP), acetone (AC), methyl acetate (MA), hydroxyisobutyraldehyde (HiBA), and formaldehyde (FA). The rate constants of the reaction of ozone and OH radicals with MTBE were found to be 0.14 and 1.9 x 10(9) M(-1) s(-1), respectively. The rate constants for the same oxidation processes were also measured for the degradation products TBF, MMP, MA, and HiBA (k(O3-TBF) = 0.78 M(-1) s(-1); k(OH-TBF) = 7.0 x 10(8) M(-1) s(-1); k(O3-MMP) = 5 M(-1) s(-1); k(OH-MMP) = 3 x 10(9) M(-1) s(-1), k(O3-MA) = 0.09 M(-1) s(-1), k(O3-HiBA) = 5 M(-1) s(-1); k(OH-HiBA) = 3 x 10(9) M(-1) s(-1)). Since all compounds reacted slowly with molecular ozone, only the degradation pathway of MTBE with OH radicals has been determined, including the formation of primary degradation products. In experiments performed with several natural waters, the efficiency of MTBE elimination and the formation of bromate as disinfection byproduct have been measured. With a bromide level of 50 microg/L, only 35-50% of MTBE could be eliminated by the AOP O3/H2O2 without exceeding the current drinking water standard of bromate (10 microg/L). The transient concentrations of MTBE and its primary degradation products were modeled using a combination of kinetic parameters (degradation product distribution and rate constants) together with the ozone and OH radical concentration and were in good agreement with the experimental results.

Characterization of the Initial Reactions during the Cometabolic Oxidation of Methyl tert -Butyl Ether by Propane-Grown Mycobacterium vaccae JOB5

“…Although previous studies have shown that TBF is a dominant oxidation product in the O 3 -and H 2 O 2 -catalyzed degradation of MTBE (1,33), this compound The reactions with filled arrows were characterized during this study and represent the proposed dominant pathway of MTBE oxidation. The putative enzymes responsible for each reaction are in italics (SCAM ϭ short-chain alkane monooxygenase; EST ϭ esterase).…”

Kinetics and mechanism for omethoate degradation by catalytic ozonation with Fe(III)-loaded activated carbon in water

“…The rate constant of an organic compound reacting with ozone is usually determined by batch experiments with addition of excess tert-butyl alcohol (t-BuOH) to inhibit potential Å OH reactions (Acero et al, 2001;Sánchez-Polo et al, 2008). From the relationship between the CT (concentration  time) value of ozone and the logarithmic decrease of a target compound, the rate constant can be derived.…”

Adsorption of methyl tert-butyl ether using granular activated carbon: Equilibrium and kinetic analysis

“…Given its high aqueous solubility, MTBE removal by traditional treatment technologies, such as air stripping has been expected to be less effective (Chang and Young, 2000;Soltanali and Shams Haghani, 2008). The byproducts of advanced oxidation process have prevented this technique from general application though it is quite effective in removing MTBE (Acero et al, 2001). Granular activated carbon (GAC) adsorption is a widely used technology for treating water contaminated with many taste-and odor-causing organics and synthetic organic chemicals, either independently or coupled with biological degradation (Suffet and Wable, 1995;El Diwani et al, 2009).…”