Adsorption of ammonia on treated stainless steel and polymer surfaces

O. Vaittinen, M. Metsälä (Corresponding Author), S. Persijn, M. Vainio, L. Halonen

Research output: Contribution to journalArticleScientificpeer-review

40 Citations (Scopus)

Abstract

Adsorption of dynamically diluted ammonia at part-per-billion to low part-per-million concentrations in dry nitrogen was studied with treated and non-treated stainless steel and polymer test tubes. The treatments included electropolishing and two types of coatings based on amorphous silicon. Cavity ring-down spectroscopy with an external cavity diode laser operating in the near-infrared wavelength range was used to monitor the adsorption process in real time in continuous-flow conditions to obtain quantitative assessment of the adsorptive properties of the studied surfaces. The investigated polymers were all less adsorptive than any of the treated or non-treated stainless steel surfaces. Some of the commercial coatings reduced the adsorption loss of stainless steel by a factor of ten or more. Polyvinylidene fluoride was found to be superior (less adsorption) to the four other studied polymer coatings. The number of adsorbed ammonia molecules per surface area obtained at different ammonia gas phase concentrations was modeled with Langmuir and Freundlich isotherms. The time behavior of the adsorption–desorption process occurring in the time scale of seconds and minutes was simulated with a simple kinetic model.
Original languageEnglish
Pages (from-to)185-196
JournalApplied Physics B: Lasers and Optics
Volume115
Issue number2
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Keywords

  • physical chemistry
  • laser technology
  • quantum optics
  • polymers
  • coatings
  • adsorption

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