紫外高级氧化的影响因素通常包括紫外因素、氧化剂因素和水体水质因素。其中紫外因素中波长的影响目前研究较少。随着紫外光源技术的发展，紫外高级氧化体系波长的选择逐渐引起关注。本研究以UV/Cl2、UV/O3两种高级氧化体系为例，使用中心波长分别为267、275和286 nm的发光二极管LED作为光源，探究了波长对UV高级氧化体系的影响。本研究讨论了波长对氧化剂吸光度和量子产率的影响，并结合吸光度和量子产率对羟基自由基的生成水平进行定量分析。结果表明，紫外剂量、摩尔吸光系数和量子产率三者的乘积F·ε·Φ能够较好表征体系羟基自由基生成水平，相同F条件下，ε·Φ越大，羟基自由基生成水平越高。具体的，对于UV/Cl2体系：pH=4条件下，波长越低，ε越大，Φ也越大，ε·Φ越大，相同F条件下[OH·]越大； pH=10条件下，波长越高，尽管Φ越小，但ε越大，ε·Φ越大，相同F条件下[OH·]越大。对于UV/O3体系：pH=4、7和10条件下，波长越低，ε越大，Φ也越大，ε·Φ越大，相同F条件下[OH·]越大。进一步以甲酸、草酸、水杨酸、单宁酸作为模型化合物，探究UV/Cl2和UV/O3体系中紫外波长对其矿化效果的影响。甲酸、草酸在250-300 nm波段没有显著吸收，当pH确定时，不同波长下有机物矿化率规律与羟基自由基生成规律基本一致，在相同F条件下矿化率能够用ε·Φ较好表征。水杨酸和单宁酸在250-300 nm波段与氧化剂存在较强竞争吸收，由此本研究引入竞争吸收系数α，F·α·ε·Φ能够较好表征有机物矿化水平，相同F条件下，α·ε·Φ越大，矿化水平越高。最后，本研究选择地表水和再生水两类实际水体，观察在原始pH条件下TOC去除情况，结果表明，对于实际水体，不同波长、相同F条件下α·ε·Φ也能够较好反映TOC去除水平。在实际应用中，选择紫外高级氧化光源的波长时，除了氧化剂吸光度、量子产率、有机物竞争吸收以外，还需要结合紫外剂量是否足够、氧化剂直接氧化能力、氧化剂剂量、水质因素（如pH、碱度、有机物成分）来综合判断。当波长因素对紫外高级氧化体系去除水体中有机物效果的影响不显著时，需要着重考虑不同波长紫外光源的成本、寿命、能耗等因素。
The factors affecting ultraviolet (UV) advanced oxidation usually include UV, oxidant and water quality. Among them, the influence of wavelength of UV light is less studied. With the development of UV light source technology, the selection of UV light with different wavelengths has gradually attracted attention. In this study, the effect of wavelength on the UV/Cl2 and UV/O3 advanced oxidation systems was investigated by using light-emitting diodes (LEDs) as UV light sources with central wavelengths of 267, 275 and 286 nm, respectively. The effects of wavelength on the absorbance and quantum yield of oxidants were discussed. And quantitative analysis of hydroxyl radical generation levels was carried out by combining the UV intensity, absorbance and quantum yield of the source. The results show that F·ε·Φ can reflect the concentration of hydroxyl radicals. Under the same UV dose, the larger the ε·Φ is, the higher production of hydroxyl radical will be. Specifically, for the UV/Cl2 system: when pH=4, the lower the wavelength is, the larger ε, Φ and ε·Φ will be, leading to higher [OH·] under the same UV dose; when pH=10, the higher the wavelength is, though Φ will be smaller, the larger ε and ε·Φ will be, leading to higher [OH·] under the same UV dose. For UV/O3 system: when pH=4, 7 and 10, the lower the wavelength is, the larger ε, Φ and ε·Φ will be, leading to higher [OH·] under the same UV dose.Further studies on the effect of wavelength on the mineralization of model compounds were conducted by using formic acid, oxalic acid, salicylic acid and tannic acid. Formic acid and oxalic acid have no absorption in the 250-300 nm band. When the pH is determined, the law of mineralization rate of organic matter at different wavelengths is basically consistent with the law of hydroxyl radical generation, which can be characterized by ε·Φ under the same UV dose. Salicylic acid and tannic acid have strong competitive absorption with the oxidants in the range of 250-300 nm. Therefore, the competitive absorption coefficient α is introduced. F·α·ε·Φ can characterize the level of organic mineralization in the ultraviolet advanced oxidation system in the presence of organic matter. Under the same UV dose, the larger the α·ε·Φ is, the higher mineralization rate of the organic matter will be. Finally, this study chose two actual water bodies, surface water and reclaimed water, to observe the removal of TOC under the original pH conditions. The results show that the α·ε·Φ can reflect the TOC removal level well for actual water bodies under different wavelengths and the same UV dose.In practice, when selecting the wavelength of the ultraviolet advanced oxidation source, in addition to the oxidant absorbance, quantum yield, and competitive absorption of organic matter, it is necessary to take the UV dose, the direct oxidation capacity of the oxidant, the oxidant dosage and the dosing method, and the water quality factors (such as pH, alkalinity and organic composition) into consideration. If the importance of wavelength is weakened in the UV advanced oxidation processes during the removal of organic matter from water, it is necessary to consider other factors including the cost, life, energy consumption, when choosing the UV light source of different wavelengths.
