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TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS
Citation:
SahleDemessie*, E. TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS. Presented at ACE Annual Meeting, Division of Environmental Chemistry, Chicago, IL, 8/26-30/2001.
Description:
The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-contaminated synthetic water and field samples from two different contaminated sites were used for these studies. Complete degradation of the MTBE was observed as a titanium dioxide concentration of 0.1 g/L within 90min. The major degradation products from MTBE were methyl tert-butyl alcohol (TBA) and tert-butyl formate (TBF) and small amounts of acetone. These degradation products appeared in the reservoir in similar concentrations, and their combined concentrations initially totaled the amount of MTBE degraded, indicating that TBF and TBA are formed within the first few reaction steps in the oxidation of MTBE. Studies conducted using contaminated groundwater samples with TiO2 and sunlight showed that aromatic organic species BTEXs, (benzene, toluene, ethylbenzene, and xylenes) were degraded up to a factor of 10 times faster than MTBE. However, dissolved metals (Fe2+) and chloride ions in contaminated water decreased the photo-activity of TiO2 for the degradation of MTBE. Reducing the pH of the grondwater samples increased the MTBE degrdation rate by three folds. Photocatalysis accelerates the solar degradation of MTBE and reduces its half-life by more than three orders of magnitude. The study indicated that solar degradation is a low cost and effective alternative to attenuate MTBE in drinking water supplies and the treatment train that combine air stripping with gas phase photooxidation is cost effective and can achieve most cleanup goals.