热解-宽带腔增强吸收光谱技术对大气总活性氮氧化物的定量研究  

Quantification of Atmospheric Total Reactive Nitrogen Oxides by Thermal Decomposition-Broadband Cavity Enhanced Absorption Spectroscopy

作　　者：邵豆 秦敏 方武 韩宝彬 唐科 解建业 赵夏丹 廖知堂 任恩伯 SHAO Dou;QIN Min;FANG Wu;HAN Bao-Bin;TANG Ke;XIE Jian-Ye;ZHAO Xia-Dan;LIAO Zhi-Tang;REN En-Bo(Key Laboratory of Environmental Optics and Technology,Chinese Academy of Sciences,Anhui Institute of Optics and Fine Mechanics,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;University of Science and Technology of China,Hefei 230026,China;College of Electrical and Opto Electronic Engineering,West Anhui University,Lu′an 237012,China)

机构地区：[1]中国科学院合肥物质科学研究院安徽光学精密机械研究所,中国科学院环境光学与技术重点实验室,合肥230031 [2]中国科学技术大学,合肥230026 [3]皖西学院电气与光电工程学院,六安237012

出　　处：《分析化学》2025年第3期387-396,共10页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.42175151);国家重点研发计划项目(No.2022YFC3701100);安徽省科技重大专项项目(No.202203a07020003)资助。

摘　　要：采用热解-宽带腔增强吸收光谱(TD-BBCEAS)技术,实现了大气中总活性氮氧化物(NO_(y))的在线实时测量。将NO_(y)高效转化为二氧化氮(NO_(2)),通过测量NO_(2)间接获得大气中总NO_(y)浓度。重点分析了一氧化氮(NO)滴定效率和其它NO_(y)组分热解效率对测量准确性的影响。通过改变流经汞灯的氧气(O_(2))流速改变滴定NO的O_(3)浓度,进而评估NO的滴定转化效率。结果表明,在O_(2)流速为6 mL/min的条件下,NO转化效率>99%。对大气NO_(y)组分中占比较大的NO_(2)、过氧乙酰硝酸酯(PAN)、硝酸(HNO_(3))以及亚硝酸(HONO)的热解效率进行测试,选择680℃作为NO_(y)高效转化的最优热解温度。分别以NO和HONO作为典型验证气体,通过汞灯及热解装置开启及关闭模式的切换,验证了NO_(y)的高效率转化以及TD-BBCEAS系统的测量准确性。在60 s积分时间下,系统对NO_(y)的检出限为2.83×10^(10)molecules/cm^(3)(60 s,2σ)。将TD-BBCEAS系统与商用NO_(y)分析仪进行了实际大气NO_(y)的对比测量,两种方法的测量结果具有良好的相关性,相关系数R2=0.98,斜率为0.93,进一步验证了TD-BBCEAS系统应用于大气总NO_(y)定量检测的可行性和准确性。Nitrogen oxides(NO_(x)=NO+NO_(2))are important precursors of ozone(O_(3)),and NO_(x) and its oxides together constitute reactive nitrogen oxides(NO_(y))in the atmosphere.A comprehensive understanding of the total NO_(y) level in the atmosphere is of great significance for a deeper understanding of the atmospheric nitrogen cycle and oxidation,as well as for formulating strategies for air pollution prevention and control.In this work,a thermal decomposition-broadband cavity enhanced absorption spectroscopy(TD-BBCEAS)technique for online measurement of total NO_(y) in the atmosphere was developed.With this method,the NO_(y) was efficiently converted into NO_(2),and the total NO_(y) concentration in the atmosphere was indirectly obtained by measuring NO_(2).Focusing on the key factors affecting the measurement of total NO_(y),the influence of NO titration efficiency and other NO_(y) component TD efficiency on measurement accuracy was emphasized.By changing the oxygen(O_(2))flow rate through the mercury lamp to alter the O_(3) concentration for titrating NO,the conversion efficiency of NO was evaluated.At O_(2) flow rate of 6 mL/min,the conversion efficiency of NO was greater than 99%.TD efficiency testing and analysis on NO_(2),peroxyacetyl nitrate(PAN),nitric acid(HNO_(3)),and nitrous acid(HONO),which account for a large proportion of atmospheric NO_(y) components,was carried out using 680℃ as the optimal TD temperature for efficient conversion of NO_(y).With NO and HONO sample gases as typical verification gases,the conversion efficiency of NO_(y) and the accuracy of NO_(y) measurement by TD-BBCEAS system were verified by switching the on and off modes of mercury lamp and TD device.At integration time of 60 s,the detection limit of the system for NO_(y) was 2.83×10^(10) molecules/cm^(3)(60 s,2σ).A comparative measurement of actual atmospheric NO_(y) was conducted between the TD-BBCEAS system and the NO_(y) analyzer.The observation results showed a correlation coefficient(R2)of 0.98 and a slope of 0.93,further v

关 键 词：活性氮氧化物 热解 宽带腔增强吸收光谱 

分 类 号：O657.3[理学—分析化学]