Effects of dissolved gas species on ultrasonic degradation of (4-chloro-2-methylphenoxy) acetic acid (MCPA) in aqueous solution
Effects of dissolved gas species on ultrasonic degradation of (4-chloro-2-methylphenoxy) acetic acid (MCPA) in aqueous solution
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DOI：
10.1016/j.ultsonch.2004.04.002
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发表时间：
2005-04-01
影响因子：
8.4
通讯作者：
Asakura, Y
中科院分区：
文献类型：
--
作者：
Kojima, Y;Fujita, T;Asakura, Y
利用频率为500 kHz的超声波，研究了稀水溶液中MCPA(4-氯-2-甲基苯氧基)乙酸的超声化学降解。在氮气(N-2)、空气(O-2/N-2)、氧气(O-2)、Ar(Ar)和Ar/O-2(60/40%v/v)气氛中，考察了气体气氛对MCPA降解的影响。对于在N-2、空气(O-2/N-2)、O-2和Ar气氛中MCPA的声化学降解，在富氧气氛中超声分解MCPA的速率比在Ar气氛中更有效。认为氧分压越高，生成的氧化剂越多，从而加速了自由基反应体系中MCPA的分解。与O-2/N-2气氛相比，Ar气氛下的脱氯率和总有机碳(TOC)的降解率都较高。结果表明，在Ar/O-2(60/40%v/v)气氛中超声降解MCPA效果最好，具有较高的分解率、脱氯率和TOC降解率。(C)2004爱思唯尔B.V.保留所有权利。
Sonochemical degradation of MCPA ((4-chloro-2-methylphenoxy) acetic acid) in dilute aqueous solutions was studied using ultrasound with a frequency of 500 kHz. The effect of gas atmosphere on MCPA degradation was investigated in nitrogen (N-2) air (O-2/N-2) oxygen (O-2), argon (Ar) and Ar/O-2 (60/40% v/v) atmospheres. For sonochemical degradation of MCPA in N-2, air (O-2/N-2), O-2 and Ar atmospheres, the rate enhancement of MCPA decomposition by sonolysis was found to be more effective in an O-2-enriched atmosphere compared to Ar atmosphere. It was considered that a higher amount of oxidants was formed in a higher O-2 partial pressure, which accelerated MCPA decomposition in a radical reaction system. On the other hand, both dechlorination and total organic carbon (TOC) removal rates were higher in Ar atmosphere, compared to those in O-2/N-2 atmosphere. It was found that, MCPA was most effectively decomposed by sonication in Ar/O-2 (60/40% v/v) atmosphere, with higher rates of decomposition, dechlorination and TOC removal. (C) 2004 Elsevier B.V. All rights reserved.