Recent studies have shown that drinking water contains up to 0.1 μg/L of prescribed drugs and are a health risk to humans. Typical water purification methods are often not effective or too costly to remove pharmaceuticals. Ultrasonic irradiation is an attractive alternative to purifying contaminated water since it can be applied to a range of water qualities and it does not require the addition chemicals or adsorbents. Diphenhydramine (DPH), the active ingredient Benadryl and other antihistamines, has been found in drinking waters. The presence of DPH even at low concentrations can be a threat to environmental and human health. Ultrasonic induced degradation is the result direct pyrolysis and hydroxyl radical induced oxidation. Our preliminary results demonstrate DPH is readily degraded by hydroxyl radicals during the ultrasound process. Within this mind, two hydroxyl radical trapping agents were used in an attempt to quantitate the amount of hydroxyl radicals produced during ultrasonic irradiation. The trapping agents produce specific hydroxyl radical products that can be readily detected using fluorescence techniques. Specifically, coumarin, a hydrophobic compound, reacts with the hydroxyl radicals to produce 7-hydroxycoumarin. Terephthalic acid, a hydrophilic compound, forms the fluorophore 2-hydroxyterephthalic acid upon reaction with hydroxyl radical. Ongoing competition experiments of DPH and each of the hydroxyl traps over a range of concentrations will provide insight about the localization of hydroxyl radical generation during ultrasonic treatment. The rates of hydroxyl radical generation determined herein will be useful for predicting treatment times for hydrophobic and hydrophilic pollutants. Our results show the rapid degradation of DPH by ultrasound is quite effective and suggest it can be used for remediation of a variety of polluted water sources.

Assessment of hydroxyl radicals production during ultrasonic irradiation for potential treatment of diphenhydramine pollution

253rd National Meeting (2017)

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