Degradation of Water Contaminants with Continuous Photoreactor

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2015-BARR-67160
Chemical products, such as methyl t-butyl ether (MTBE), 1,4-dioxane (DIOX), ethyl t-butyl ether (ETBE), t-amyl methyl ether (TAME), and diisopropyl ether (DIPE), are commonly used as solvents and gasoline additives. All have recently exhibited a presence in public water systems and are a significant cause of water contamination. These compounds are soluble in water and are chemically stable. Therefore, removal can be both expensive and difficult to apply to large systems. Recent approaches, such as activated carbon, can be applied to ether contamination, but its bed life is diminished by up to 75 percent, and then, the activated carbon must be collected and incinerated to destroy the contamination. Air stripping is another approach, but is costly and not very effective due to the high solubility of MTBE and DIOX. In addition, chemical treatment, such as hydrogen peroxide and Cu/Fe reagent or KMnO4, can produce dangerous amounts of heat and can leave metal cations in the solution. Hence, there is an unmet need to find an effective removal system that is applicable to larger scale municipal water systems.

Researchers at Purdue University have designed a series of continuous flow photoreactors that can effectively remove these compounds. MTBE, ETBE, TAME, DIOX, and DIPE undergo a degradation process involving visible/near UV light (300-600nm). Therefore, TiO2 coated glass tubing or beads are placed and water soluble ethers can be partially degraded using simple fluorescent lighting, up to 15 percent in less than two meters of reaction flow distance. This system is advantageous because oxygen concentration is kept constant throughout the process, so destruction of the substrate is not limited by oxygenation of the solution. Second, by coating the TiO2 onto surfaces of glass beads, there are no in-solution reaction components, catalyst, or products that must be dealt with at the end. Third, the results demonstrate that the same process can also work for other water soluble ethers. Finally, the reactor design is not limited by size and is expandable to larger municipal water systems that use larger flow rates, and thereby, resulting in improved degradation of many dangerous water contaminants.

Advantages:
-Effective removal of water contaminants
-Constant oxygenation and no in-solution reactions
-Reactor not limited by size

Potential Applications:
-Public water systems
Jun 10, 2016
Utility Patent
United States
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Jun 10, 2015
Provisional-Patent
United States
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Purdue Office of Technology Commercialization
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Email: otcip@prf.org