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J Air Waste Manag Assoc

Title:		Effect of pH and temperature on the kinetics of odor oxidation using chlorine dioxide
Author(s):		Kastner JR; Das KC; Hu C; McClendon R;
Address:		"Department of Biological and Agricultural Engineering, University of Georgia, Athens, Georgia 30602, USA. jkastner@engr.uga.edu"
Journal Title:		J Air Waste Manag Assoc
Year:		2003
Volume:		53
Issue:		10
Page Number:		1218 - 1224
DOI:		10.1080/10473289.2003.10466282
ISSN/ISBN:		1096-2247 (Print) 1096-2247 (Linking)
Abstract:		"Increasing public concerns over odors and air regulations in nonattainment zones necessitate the remediation of a wide range of volatile organic compounds (VOCs) generated in the poultry-rendering industry. Currently, wet scrubbers using oxidizing chemicals such as chlorine dioxide (ClO2) are utilized to treat VOCs. However, little information is available on the kinetics of ClO2 reaction with rendering air pollutants, limiting wet scrubber design and optimization. Kinetic analysis indicated that ClO2 does not react with hexanal and 2-methylbutanal regardless of pH and temperature and implied that aldehyde removal occurs primarily via mass transfer. Contrary to the aldehydes, ethanethiol or ethyl mercaptan (a model compound for methanethiol or methyl mercaptan) and dimethyl disulfide (DMDS) rapidly reacted with ClO2. The overall reaction was found to be second and third order for ethanethiol and DMDS, respectively. Moreover, an increase in pH from 3.6 to 5.1 exponentially increased the reaction rate of ethanethiol (e.g., k2 = 25-4200 L/mol/sec from pH 3.6 to 5.1) and significantly increased the reaction rate of DMDS if increased to pH 9 (k3 = 1.4 x 10(6) L2/mol2/sec). Thus, a small increase in pH could significantly improve wet scrubber operations for removal of odor-causing compounds. However, an increase in pH did not improve aldehyde removal. The results explain why aldehyde removal efficiencies are much lower than methanethiol and DMDS in wet scrubbers using ClO2"
Keywords:		"*Abattoirs Air Pollution/*prevention & control Chlorine Compounds/*chemistry Hydrogen-Ion Concentration Kinetics *Models, Theoretical *Odorants Oxidation-Reduction Oxides/*chemistry Temperature;"
Notes:		"MedlineKastner, James R Das, Keshav C Hu, Cheng McClendon, Ron eng Research Support, Non-U.S. Gov't 2003/11/08 J Air Waste Manag Assoc. 2003 Oct; 53(10):1218-24. doi: 10.1080/10473289.2003.10466282"