Ozone microbubble-aided intensification of degradation of naproxen in a plant prototype. Issue 3 (June 2019)

• Record Type: Journal Article
• Authors: Patel, Surabhi; Majumder, Subrata Kumar; Das, Papita; Ghosh, Pallab
• Is Part Of: Journal of environmental chemical engineering. Volume 7:Issue 3(2019)
• Publication Date: 2019-06
• Subjects: Degradation -- Kinetics -- Microbubble -- Ozonation -- Pharmaceuticals; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2019.103102
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: Use of peroxone (O3 +H2 O2 ) in a microbubble system degraded the naproxen rapidly. In-situ hydroxyl radical generation enhanced the process efficiently. Main step of naproxen degradation was found decarboxylation More than 90% naproxen was degraded within 6 min of ozonation. Abstract: Naproxen (NPX), one of the best-selling nonsteroidal anti-inflammatory drugs, is found in surface and drinking water at concentrations up to 1 μg dm −3 . It has been emerging as a water contaminant during the last two decades. Conventional removal techniques, i.e. sewage treatment, membrane separation, filtration, and adsorption have been found to be inefficient for complete removal of NPX. Intensification of the wastewater treatment processes is important in order to achieve higher degradation efficiencies. Advanced oxidation processes (i.e. ozonation, photolysis, and photo-Fenton) have the greater capability of NPX removal. In the present study, a combination of ozonated microbubbles and H2 O2 was used for effective removal of NPX. The use of microbubbles increased the mass transfer into the aqueous phase. Use of H2 O2 with ozone increased the degradation process significantly, which confirms the − the hydroxyl radicals generated in situ under the alkaline conditions. The ozone supply rates were 0.39, 0.41, 0.44, and 0.48 mg s −1 and the corresponding reaction times were 10000, 2400, 840, and 240 s, respectively for 98−99% conversion for pH 9. The pseudo first-order reaction constants or O3 alone and H2 O2 + O3 were in the range of 2.89 × 10 −3 − 6.44 × 10 −3 and 3.39 × 10 −3 − 13.6 × 10 −3 min −1, respectively. The effects of ozone supply rate and pH of the reaction system were also studied. The by-products were identified and a mechanism of ozonation of NPX was proposed. The main intermediates were 2-methoxy-6-ethyl naphthalene, (2-methoxy-6-methyl naphthalene, and 1-(6-methoxynaphtalen-2-yl) ethyl-hydroperoxide.