The use of impregnated filters to collect traces of gases in the atmosphere

Analysis of Sulfur-Containing Gases in the Ambient Air Using Selective Pre-Filters and a Micro-coulometric Detector

“…The optimum pH, the filter formulations, and the retention efficiencies for the most effective filters for the five gases are given in Table II. A membrane filter impregnated with 5% sodium bicarbonate effectively removed sulfur dioxide and passed 90% or more of the other four compounds studied. This corroborated the findings of Pate, et al, 3 who collected sulfur dioxide from the atmosphere with a potassium bicarbonate impregnated membrane filter. The addition of sodium carbonate or potassium acid phthalate to sodium bicarbonate to adjust the pH of the bicarbonate filter over the range from 7 to 11 did not significantly change the filter specificity.…”

“…Oeveral analytical processes, including conductivity, x color imetry, 2 light-absorption, 3 fluorescence quenching, 4 and coulometry, 5 have been used for the continuous, automatic analysis of sulfur-containing gases in the atmosphere. Numerous commercial and home-made, direct-reading instruments have been produced embodying modifications of these techniques.…”

“…17 Numerous advantages of the dry filtration system over liquid collection media have been reported by Lodge, et al ls In addition, a dry separating system would be more adaptable to an automatic field monitoring system than a wet separation system. Pate, et al, 3 found that membrane filters which had been impregnated with 5% potassium bicarbonate and then dried, quantitatively collected SO2 from air samples with an efficiency of 100%. Lead acetate-impregnated membrane filter tape has been used to remove H 2 S from sampled air.…”

H2S fluxes from Mt. Etna, Stromboli, and Vulcano (Italy) and implications for the sulfur budget at volcanoes

“…Filter pack measurements involved pumping plume air at a constant flow rate (4 L · min Ϫ1 for 30 min) through a sampler consisting of two filter holders arranged in parallel. The first filter holder contained one particulate and three 1M NaOH-impregnated filters in series (Aiuppa et al, 2002;Aiuppa et al, 2004a), allowing determination of SO 2 according to a standard procedure (Pate et al, 1963;Johnson et al, 1975;Finnegan et al, 1989). (Note that NaOH-treated filters do not appreciably retain H 2 S, due to its weak Lewis acid nature; Finnegan et al, 1989.)…”

Simultaneous collection of particles and gases followed by multielement analysis using nuclear techniques

“…Sulfur dioxide has been collected with impregnated filters containing KOH (Huygen, 1963;Lewin and Zachau-Christiansen, 1977;Fogg and Rahn, 1984), K2CO3 (Huygen, 1963;Johnson and Atkins, 1975), KHCO3 (Huygen, 1963;Pate et al, 1963), and LiOH (Finnegan, 1984;Kitto et al, 1983). Gaseous halogens have been collected on filters containing tetrabutyl ammonium hydroxide (TBAH) (Rahn et aL, 1977;Lazrus (t al., 1975) and LiOH (Finnegan, 1984;Kitto et al, 1983;Rahn et al, 1976).…”