Kidak R, Ince N H
Bogazici University, Institute of Environmental Sciences, Bebek, 34342, Istanbul, Turkey.
J Hazard Mater. 2007 Jul 31;146(3):630-5. doi: 10.1016/j.jhazmat.2007.04.106. Epub 2007 May 4.
The present study is about the enhancement in ozone-mediated degradation and UV (254nm) photolysis of phenol in aqueous solutions by 300kHz acustic cavitation and the selection of operating parameters for optimum phenol removal efficiency. The method was based on monitoring of the concentration of phenol during 90min exposure to ozonation, sonication, UV photolysis, O(3)/ultrasound, UV/ultrasound and O(3)/UV/ultrasound operations. It was found that ozonation at alkaline pH was an effective method of phenol destruction, but it was considerably more effective when applied simultaneously with ultrasonic irradiation. The observed synergy particularly at alkaline pH was attributed to combined effects of: (i) increased ozone mass transfer (upon hydrodynamic shear forces created by ultrasonic bubbles) and (ii) excess hydroxyl radical formation (upon thermal decomposition of ozone in the gaseous cavity bubbles). Degradation of phenol by photolysis alone was negligible, while combination of UV-irradiation and ultrasound rendered considerable degrees of decay. The synergy here was explained by excess hydroxyl radicals that are formed by photolysis of ultrasound-generated H(2)O(2). Maximum rate of phenol degradation was observed in case of combined application of ozone, UV and ultrasound at basic pH.
本研究旨在探讨300kHz声空化对水溶液中臭氧介导的苯酚降解及紫外（254nm）光解的增强作用，以及选择最佳苯酚去除效率的操作参数。该方法基于在90分钟的臭氧化、超声处理、紫外光解、臭氧/超声、紫外/超声和臭氧/紫外/超声操作过程中监测苯酚浓度。研究发现，碱性pH条件下的臭氧化是一种有效的苯酚破坏方法，但与超声辐照同时应用时效果更佳。观察到的协同作用，尤其是在碱性pH条件下，归因于以下综合效应：（i）臭氧传质增加（由超声气泡产生的流体动力剪切力引起）和（ii）过量羟基自由基的形成（由气态腔泡中臭氧的热分解引起）。单独光解对苯酚的降解可忽略不计，而紫外辐照与超声的组合则导致相当程度的衰减。这里的协同作用是由超声产生的H₂O₂光解形成的过量羟基自由基来解释的。在碱性pH条件下联合应用臭氧、紫外和超声时，观察到苯酚降解的最大速率。
