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International Journal of Photoenergy
Volume 2013 (2013), Article ID 916849, 9 pages
http://dx.doi.org/10.1155/2013/916849
Research Article

Kinetic Modeling for Microwave-Enhanced Degradation of Methylene Blue Using Manganese Oxide

1Department of Safety, Health, and Environmental Engineering, Ming Chi University of Technology, 84 Gung-Juan Road, Taishan, New Taipei 24301, Taiwan
2School of Public Health, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110, Taiwan
3Department of Soil and Environmental Science, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan

Received 19 September 2012; Revised 13 December 2012; Accepted 13 December 2012

Academic Editor: Jafar Soltan

Copyright © 2013 Wen-Hui Kuan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study was originally performed to compare the MnO2-based degradation of aqueous methylene blue (MB) under microwave irradiation- (MW-) enhanced and conventional heating- (CH-) enhanced conditions. The degradation process and kinetics were investigated to elucidate the microwave effect on the reaction. The results showed that all three tested conditions, sole MnO2, MnO2/CH, and MnO2/MW, followed the third-order (second upon MB and first upon MnO2) kinetic model. However, a higher degradation rate of MB was available under the MW-enhanced process, which implies that the “athermal effect” of MW might be of more benefit for the generation of electrophilic oxygen ions ( , , and ) to degrade MB. The results showed that the degradation percentage of MB could reach 100%, corresponding to 92% total organic carbon (TOC) removal under microwave irradiation at pH 7.20 for 10 min.