| Physical insights into the sonochemical degradation of recalcitrant organic pollutants with cavitation bubble dynamics. | |
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MedLine Citation:
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PMID: 19321374 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This paper tries to discern the mechanistic features of sonochemical degradation of recalcitrant organic pollutants using five model compounds, viz. phenol (Ph), chlorobenzene (CB), nitrobenzene (NB), p-nitrophenol (PNP) and 2,4-dichlorophenol (2,4-DCP). The sonochemical degradation of the pollutant can occur in three distinct pathways: hydroxylation by ()OH radicals produced from cavitation bubbles (either in the bubble-bulk interfacial region or in the bulk liquid medium), thermal decomposition in cavitation bubble and thermal decomposition at the bubble-liquid interfacial region. With the methodology of coupling experiments under different conditions (which alter the nature of the cavitation phenomena in the bulk liquid medium) with the simulations of radial motion of cavitation bubbles, we have tried to discern the relative contribution of each of the above pathway to overall degradation of the pollutant. Moreover, we have also tried to correlate the predominant degradation mechanism to the physico-chemical properties of the pollutant. The contribution of secondary factors such as probability of radical-pollutant interaction and extent of radical scavenging (or conservation) in the medium has also been identified. Simultaneous analysis of the trends in degradation with different experimental techniques and simulation results reveals interesting mechanistic features of sonochemical degradation of the model pollutants. The physical properties that determine the predominant degradation pathway are vapor pressure, solubility and hydrophobicity. Degradation of Ph occurs mainly by hydroxylation in bulk medium; degradation of CB occurs via thermal decomposition inside the bubble, degradation of PNP occurs via pyrolytic decomposition at bubble interface, while hydroxylation at bubble interface contributes to degradation of NB and 2,4-DCP. |
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Authors:
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Thirugnanasambandam Sivasankar; Vijayanand S Moholkar |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-02-27 |
Journal Detail:
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Title: Ultrasonics sonochemistry Volume: 16 ISSN: 1873-2828 ISO Abbreviation: Ultrason Sonochem Publication Date: 2009 Aug |
Date Detail:
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Created Date: 2009-05-29 Completed Date: 2009-10-20 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9433356 Medline TA: Ultrason Sonochem Country: Netherlands |
Other Details:
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Languages: eng Pagination: 769-81 Citation Subset: IM |
Affiliation:
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Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Free Radicals
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chemistry Organic Chemicals / chemistry* Ultrasonics* Waste Management / instrumentation* Water Pollutants, Chemical / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Free Radicals; 0/Organic Chemicals; 0/Water Pollutants, Chemical |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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