Evaluation of cation exchange membrane performance under exposure to high Hg0 and HgBr2 concentrations

Matthieu B. Miller, Sarrah M. Dunham-Cheatham, Mae Sexauer Gustin*, Grant C. Edwards

*Corresponding author for this work

    Research output: Contribution to journalArticle

    7 Citations (Scopus)

    Abstract

    Reactive mercury (RM), the sum of both gaseous oxidized Hg and particulate bound Hg, is an important component of the global atmospheric mercury cycle, but measurement currently depends on uncalibrated operationally defined methods with large uncertainty and demonstrated interferences and artifacts. Cation exchange membranes (CEMs) provide a promising alternative methodology for quantification of RM, but method validation and improvements are ongoing. For the CEM material to be reliable, uptake of gaseous elemental mercury (GEM) must be negligible under all conditions and RM compounds must be captured and retained with high efficiency. In this study, the performance of CEM material under exposure to high concentrations of GEM (1:43×106 to 1:85×106 pgm-3) and reactive gaseous mercury bromide (HgBr2 ∼ 5000 pgm-3) was explored using a custom-built mercury vapor permeation system. Quantification of total permeated Hg was measured via pyrolysis at 600 °C and detection using a Tekran® 2537A. Permeation tests were conducted over 24 to 72 h in clean laboratory air, with absolute humidity levels ranging from 0.1 to 10 gm-3 water vapor. GEM uptake by the CEM material averaged no more than 0.004% of total exposure for all test conditions, which equates to a non-detectable GEM artifact for typical ambient air sample concentrations. Recovery of HgBr2 on CEM filters was on average 127% compared to calculated total permeated HgBr2 based on the downstream Tekran® 2537A data. The low HgBr2 breakthrough on the downstream CEMs (<1 %) suggests that the elevated recoveries are more likely related to suboptimal pyrolyzer conditions or inefficient collection on the Tekran® 2537A gold traps.

    Original languageEnglish
    Pages (from-to)1207-1217
    Number of pages11
    JournalAtmospheric Measurement Techniques
    Volume12
    Issue number2
    DOIs
    Publication statusPublished - 26 Feb 2019

    Bibliographical note

    Copyright the Author(s) 2019. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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