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Environ Sci Technol

Title:		Comparison of toluene removal in air at atmospheric conditions by different corona discharges
Author(s):		Schiorlin M; Marotta E; Rea M; Paradisi C;
Address:		"Department of Chemical Sciences, Universita di Padova, 35131 Padova, Italy"
Journal Title:		Environ Sci Technol
Year:		2009
Volume:		43
Issue:		24
Page Number:		9386 - 9392
DOI:		10.1021/es9021816
ISSN/ISBN:		0013-936X (Print) 0013-936X (Linking)
Abstract:		"Different types of corona discharges, produced by DC of either polarity (+/-DC) and positive pulsed (+pulsed) high voltages, were applied to the removal of toluene via oxidation in air at room temperature and atmospheric pressure. Mechanistic insight was obtained through comparison of the three different corona regimes with regard to process efficiency, products, response to the presence of humidity and, for DC coronas, current/voltage characteristics coupled with ion analysis. Process efficiency increases in the order +DC < -DC < +pulsed, with pulsed processing being remarkably efficient compared to recently reported data for related systems. With -DC, high toluene conversion and product selectivity were achieved, CO(2) and CO accounting for about 90% of all reacted carbon. Ion analysis, performed by APCI-MS (Atmospheric Pressure Chemical Ionization-Mass Spectrometry), provides a powerful rationale for interpreting current/voltage characteristics of DC coronas. All experimental findings are consistent with the proposal that in the case of +DC corona toluene oxidation is initiated by reactions with ions (O(2)(+*), H(3)O(+) and their hydrates, NO(+)) both in dry as well as in humid air. In contrast, with -DC no evidence is found for any significant reaction of toluene with negative ions. It is also concluded that in humid air OH radicals are involved in the initial stage of toluene oxidation induced both by -DC and +pulsed corona"
Keywords:		"*Air Atmospheric Pressure Carbon Dioxide/chemistry Carbon Monoxide/chemistry Electrochemistry/*methods Humidity Oxidation-Reduction Spectroscopy, Fourier Transform Infrared Temperature Toluene/chemistry Volatile Organic Compounds/chemistry;"
Notes:		"MedlineSchiorlin, Milko Marotta, Ester Rea, Massimo Paradisi, Cristina eng Research Support, Non-U.S. Gov't 2009/12/17 Environ Sci Technol. 2009 Dec 15; 43(24):9386-92. doi: 10.1021/es9021816"