Inoue Marcio, Okada Fumio, Sakurai Akihiko, Sakakibara Mikio
Department of Applied Chemistry and Biotechnology, University of Fukui, Bunkyo 3-9-1, Fukui 910-8507, Japan.
Ultrason Sonochem. 2006 May;13(4):313-20. doi: 10.1016/j.ultsonch.2005.05.003. Epub 2005 Jul 12.
Dyestuffs are often present in industrial wastewaters and can consist of hazardous substances which have a serious impact on the environment and personal health. This report describes a system developed to degrade these substances using sonochemical reactions. Ultrasonic frequencies of 118, 224, 404 and 651 kHz and power input values of 11.4, 29.0 and 41.5 W were tested on Rhodamine B and Orange II dyestuff solutions in order to find the best degradation conditions. The ultrasonic irradiation of air-saturated solutions produces free radicals that combine and generates hydrogen peroxide, and compared to the production of hydrogen peroxide when irradiating water, a decrease was found during the irradiation to dyestuff solutions, indicating that some of the free radicals were consumed in the dyestuffs degradation process. The effects of the ultrasonic irradiation conditions on the pH, nitric and nitrous acid formations as well as the total organic carbon value (TOC) were also investigated. For the ultrasonic frequencies of 224, 404 and 651 kHz, the degradation rates were very similar, however, the 118 kHz system presented a degradation rate of about one-third that of the higher frequencies for both dyestuffs. The Rhodamine B solutions were decolorized within 2 h of ultrasonic irradiation for all systems with the exception of the 118 kHz one. For Orange II, except for the 118 kHz system, all solutions were decolorized within 4 h of ultrasonic irradiation. All reactions were carried out at 25 degrees C and the total ultrasonic irradiation time was 10 h.
染料通常存在于工业废水中，可能包含对环境和人体健康有严重影响的有害物质。本报告描述了一种利用声化学反应降解这些物质的系统。对罗丹明B和橙黄II染料溶液测试了118、224、404和651 kHz的超声频率以及11.4、29.0和41.5 W的功率输入值，以找到最佳降解条件。对空气饱和溶液进行超声辐照会产生自由基，这些自由基结合生成过氧化氢，与辐照水时过氧化氢的生成量相比，辐照染料溶液时发现过氧化氢生成量减少，这表明一些自由基在染料降解过程中被消耗。还研究了超声辐照条件对pH值、硝酸和亚硝酸形成以及总有机碳值（TOC）的影响。对于224、404和651 kHz的超声频率，降解速率非常相似，然而，118 kHz系统对两种染料的降解速率约为较高频率系统的三分之一。除118 kHz系统外，所有系统的罗丹明B溶液在超声辐照2小时内均被脱色。对于橙黄II，除118 kHz系统外，所有溶液在超声辐照4小时内均被脱色。所有反应均在25℃下进行，超声辐照总时间为10小时。
