摘要
以饮用水中痕量氯仿、四氯化碳和一溴二氯甲烷3种卤代甲烷为目标化合物,采用超声辐照技术研究它们在不同条件下的去除效果。结果表明,3种卤代甲烷的超声降解遵循准一级反应动力学模型,超声辐照1 h后的去除效率与速率常数均按氯仿、一溴二氯甲烷、四氯化碳的顺序递增,分子的疏水性对3种卤代甲烷的降解效率有显著影响。超声强度越大,饮用水中的痕量卤代甲烷去除效果越好。超声辐照后自来水的pH值降低很小,进一步论证超声技术应用于饮用水处理的可行性。在敞口容器中,超声波辐照对水样中的卤代甲烷同时存在着降解与吹脱作用,根据超声空化理论,提出可能的超声吹脱机理。
The removals of CHC;3 , CCl4 and CHBrCl2, with very low initial concentrations in the chlorinated drinking water under ultrasonic irradiation at different conditions were investigated. It is observed that the removal efficiencies and the sonolysis rate constants of three halomethanes after 1 h ultrasonic irradiation fitted the following increasing order：CHCl3 〈 CHBrCl2 〈 CCl4, and the degradation of halomethanes studied followed the pseudo-first-order kinetics model, respectively. Meanwhile, molecular hydrophobicity was found to be a crucial factor in controlling the sonodegradation of halomethane mixtures. Additionally, acoustic intensity also remarkably influenced the sonodegradation of halomethanes, a higher acoustic intensity led to a better removal efficiency of halomethanes. A slight decrease in pH values of drinking water during the sonodegradation processes further demonstrates that ultrasonic technology is practical in the treatment of chlorinated drinking water. It is also concluded that the ultrasonic stirring and degradation coexisted when the halomethanes were irradiated in the unsealed vessel. Based on the ultrasonic cavitation theory, a possible mechanism of the ultrasonic stirring is put forward.
出处
《南京气象学院学报》
CSCD
北大核心
2007年第5期710-714,共5页
Journal of Nanjing Institute of Meteorology
基金
江苏省高新技术项目(BG2001040)
污染控制与资源化研究国家重点实验室开放课题
南京信息工程大学科研启动基金资助项目(QD54)
关键词
卤代甲烷
超声辐照
降解
halomethane
ultrasonic irradiation
degradation
