The effect of vapor polarity and boiling point on breakthrough for binary mixtures on respirator carbon.
Am Ind Hyg Assoc J 1996 Aug; 57(8):717-723
In an effort to predict the service life of activated carbon respirator cartridges, the role of vapor polarity on breakthrough times was studied using the Wheeler model. The Wheeler model, which was developed to predict adsorbent bed behavior in dynamic systems, was described. Breakthrough was tested using a gas chromatograph containing both flame ionization detectors (FID) and photoionization detectors (PID). Binary mixtures containing one PID responsive component (test vapor) were studied in the presence of a second vapor (probe vapor). Vapor challenges on carbon beds were conducted for p-xylene (1330207) and pyrrole (109977) as test vapors, individually, and in binary mixtures with the polar and nonpolar probe vapors toluene (108883), p-fluorotoluene (352329), o- dichlorobenzene (95501), and p-dichlorobenzene (106467). The 1% breakthrough time (1% BTT), kinetic adsorption capacity (KAC), and the rate constant of the Wheeler model were unaffected by the probe vapor polarity. The Wheeler model, using single vapor data, reasonably estimated the 1% BTT and KAC for test vapors in binary mixtures. Total vapor concentration was primarily responsible for the 1% BTT in both single and binary systems. The KAC was proportional to the fractional molar concentration of the test vapor in mixtures. Differences seen in the rate constant for p-xylene compared with the probe boiling point did not appear to be of significant importance in estimating the 1% BTT for the range of boiling points tested. An effect due to probe boiling point was possible, and tests with chemicals of more widely ranging boiling points was recommended. The authors conclude that these results emphasize the importance of consideration of other vapors when estimating the service life of a respirator for a vapor in a mixture.
NIOSH-Publication; NIOSH-Grant; Respirators; Mathematical-models; Chemical-properties; Chemical-cartridge-respirators; Respiratory-equipment; Toxic-vapors; Chlorinated-hydrocarbons
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Respirator Research; Respirators
American Industrial Hygiene Association Journal
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