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Importance of PCDD/F molecules’ polarizability and steric hindrance on their adsorption onto zeolites in a standard EN1948-1 sampling device for incinerator emission monitoring
Chemosphere ( IF 8.1 ) Pub Date : 2020-06-29 , DOI: 10.1016/j.chemosphere.2020.127457
Oliver Schäf , Laurence Tortet , Angélique Simon-Masseron , Joël Patarin , Stephanie Defour , Rosine Blanc , Christophe Coste , Yves Zerega

Currently, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) monitoring at stationary sources uses short- and long-term sampling methods compliant with EN1948 standard. The XAD-2 resin is exposed to gas stream for 3–4 weeks (long term), and subsequently analysed in an accredited laboratory for 2 weeks. With the aim of developing an on-line mass spectrometer device using adsorption onto a set of different zeolites as specific adsorbents prior to mass analysis, the paper proposes to firstly test zeolites within the methods compliant with EN1948 standard.

In addition to the non-specific external surface adsorption, zeolites possess micropores for adsorbing molecules specifically. Zeolites allowing selective adsorption of only tetra- and penta-chlorinated toxic congeners (TeCDD/F, PeCDD/F) were exposed to the gas flow of a household waste incinerator. As the extraction method of EN 1948 standard does not allow us to discern the two types of adsorption, the adsorbents have been tested at a sampling point located before the last filter. With high congener concentrations, it is expected that the dynamic adsorption properties of the zeolites can be deduced from the breakthrough of some congeners.

The electronic interactions between zeolite surface area and PCDD/F involve the polarizability of the molecules. Thanks to the congener breakthrough comparing two zeolite structure types, it has been deduced that toxic TeCDD/F and PeCDD/F were adsorbed in the micropores of FAU-NaX zeolite due to steric compatibility of these congeners. Moreover, the partition of congeners between the condensate and gas phase was elucidated by considering the polarizability of PCDD/F molecules.



中文翻译:

在用于焚烧炉排放监测的标准EN1948-1采样设备中,PCDD / F分子的极化性和其吸附到沸石上的位阻的重要性

当前,固定源的多氯二苯并对二恶英和多氯二苯并呋喃(PCDD / F)监测使用符合EN1948标准的短期和长期采样方法。将XAD-2树脂暴露于气流中3-4周(长期),然后在认可的实验室中进行2周的分析。为了开发一种在线质谱仪设备,在质量分析之前将其吸附在一组不同的沸石上作为特定的吸附剂,本文建议首先在符合EN1948标准的方法中测试沸石。

除非特异性外表面吸附外,沸石还具有用于特异性吸附分子的微孔。仅允许选择性吸附四氯化和五氯化有毒同类物(TeCDD / F,PeCDD / F)的沸石暴露于生活垃圾焚化炉的气流中。由于EN 1948标准的提取方法无法区分两种吸附类型,因此已经在最后一个过滤器之前的采样点对吸附剂进行了测试。在高同类物浓度的情况下,预期可以从某些同类物的突破中推断出沸石的动态吸附性能。

沸石表面积和PCDD / F之间的电子相互作用涉及分子的极化性。由于比较两种沸石结构类型的同族物突破,已推断出由于这些同族物的空间相容性,有毒的TeCDD / F和PeCDD / F被吸附在FAU-NaX沸石的微孔中。此外,通过考虑PCDD / F分子的极化性,阐明了冷凝物和气相之间同类物的分配。

更新日期:2020-07-08
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