Department of Civil and Mineral Engineering , University of Toronto , 35 St. George Street , Toronto , Ontario M5S 1A4 , Canada.
Hazen and Sawyer , 1555 Roseneath Road , Richmond , Virginia 23230 , United States.
Environ Sci Technol. 2020 Feb 4;54(3):1929-1937. doi: 10.1021/acs.est.9b06273. Epub 2020 Jan 10.
The hydroxyl radical (OH) scavenging capacity is a useful parameter for the design and operation of an advanced oxidation process (AOP) in water treatment. The scavenging capacity may change with time, and it would be useful to continuously measure this change to be able to optimize AOP doses. In this study, we first reviewed current methods for scavenging capacity measurement to identify strengths and weaknesses of each method. This information helped guide the design of an external calibration method to allow straightforward laboratory and field measurement of OH scavenging capacity. The method used low-pressure UV/HO as the OH generation system, methylene blue (MB) as the probe compound, and isopropyl alcohol (IPA) as the standard. By monitoring, offline, the color decay of MB in a series of IPA solutions with different scavenging capacity, a calibration curve was established between the color decay rate and the scavenging capacity. The measured color decay in real water samples can then be used with this external calibration to estimate their scavenging capacity. Work was undertaken to ensure that the process would be robust under a wide range of water quality conditions. Parallel tests using this method compared with the benchmark methods confirmed its robustness and accuracy.
羟基自由基 (OH) 清除能力是水处理中高级氧化工艺 (AOP) 设计和运行的一个有用参数。清除能力可能随时间而变化，连续测量这种变化将有助于优化 AOP 剂量。在本研究中，我们首先回顾了当前的清除能力测量方法，以确定每种方法的优缺点。这些信息有助于指导外部校准方法的设计，以便能够在实验室和现场直接测量 OH 清除能力。该方法使用低压 UV/HO 作为 OH 产生系统，亚甲基蓝 (MB) 作为探针化合物，异丙醇 (IPA) 作为标准。通过在线监测一系列具有不同清除能力的 IPA 溶液中亚甲蓝的颜色衰减，建立了颜色衰减率与清除能力之间的校准曲线。然后可以使用该外部校准来估计实际水样的测量颜色衰减，以估算其清除能力。进行了工作以确保该过程在广泛的水质条件下具有稳健性。使用该方法与基准方法进行的平行测试证实了其稳健性和准确性。
