Evaluate UV-LEDs for UV/Chlorine Advanced Oxidation

评估 UV-LED 的 UV/氯高级氧化能力

• 批准号: 543602-2019
• 负责人: Andrews, Susan
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680667
• 关键词: Evaluate; UV; LEDs; Chlorine; Advanced

Ultraviolet light-emitting diodes (UV LEDs) are fast becoming an attractive water treatment tool to disinfect the microorganisms and to remove the micropollutants. Different from the conventional mercury lamps which are currently adopted by the water treatment plants, they are compact, mercury-free, and can be turned on and off instantly. As such, they have the potential to replace conventional UV lamps. One of the more novel applications for LEDs in water treatment is in advanced oxidation processes (AOPs). In UV-based AOPs, UV light is used to split chemicals into reactive 'radical' species that can quickly destroy pollutants in water. To-date, most UV-based AOPs employ mercury lamps to generate the UV light. However, among the different known AOPs, UV/Cl2, which uses UV photons to split chlorine into radicals, may be particularly well-suited to using LEDs as the light source. This is because chlorine shows a high UV absorptivity at the wavelengths where UV LEDs can produce light more efficiently than conventional mercury lamps. Unfortunately, there is no information on the performance of UV LEDs relative to mercury lamps in the context of micropollutant removal by UV/Cl2, nor is there information on the byproducts that may be generated and whether or not they may be toxic. For example, chlorate, is known to form from radicals produced during UV/Cl2 processes that employ conventional UV lamps, and the government of Ontario currently regulates chlorate at 1 mg/L in drinking water due to its toxicity. It is hypothesized that the specific radicals leading to chlorate may be less predominant when using LEDs due to their low intensity and low energy UV output. This will be the first study evaluating the UV/Cl2 AOP by quantifying the competitiveness of LEDs relative to low and medium pressure mercury lamps on the basis of (1) the control of micropollutants and (2) the production of chlorate and other relevant byproducts.

紫外光发光二极管(UV LED)正在迅速成为一种具有吸引力的水处理工具，用于消毒微生物和去除微污染物。与目前水处理厂采用的传统汞灯不同，它们结构紧凑，不含汞，可以立即开启和关闭。因此，它们有可能取代传统的紫外线灯。LED在水处理中的最新应用之一是在高级氧化工艺(AOPS)中。在基于紫外线的AOPS中，紫外光被用来将化学物质分解成活性的“自由基”物种，这些物种可以迅速摧毁水中的污染物。到目前为止，大多数基于紫外线的AOPS都使用水银灯来产生紫外线。然而，在不同的已知AOPS中，使用UV光子将氯分解为自由基的UV/Cl2可能特别适合使用LED作为光源。这是因为氯在紫外线LED可以比传统汞灯更有效地产生光的波长上显示出高的紫外线吸收能力。不幸的是，在用UV/Cl2去除微污染物的情况下，没有关于UV LED相对于汞灯的性能的信息，也没有关于可能产生的副产品以及它们是否有毒的信息。例如，众所周知，氯酸盐是由使用传统紫外线灯的UV/Cl2过程中产生的自由基形成的，由于氯酸盐的毒性，安大略省政府目前规定饮用水中的氯酸盐含量为1毫克/L。假设在使用LED时，由于其低强度和低能量的紫外光输出，导致氯酸盐的特定自由基可能不太占优势。这将是第一项评估UV/Cl2 AOP的研究，方法是根据(1)微污染物的控制和(2)氯酸盐和其他相关副产品的生产，量化LED相对于低压和中压汞灯的竞争力。