Open AccessEstimation of Organic Vapor Breakthrough in Humidified Activated Carbon Beds: —Application of Wheeler‐Jonas Equation, NIOSH MultiVapor™ and RBT (Relative Breakthrough Time)
Author(s) -
Abiko Hironobu,
Furuse Mitsuya,
Takano Tsuguo
Publication year - 2016
Publication title -
journal of occupational health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 59
ISSN - 1348-9585
DOI - 10.1539/joh.15-0244-oa
Subject(s) - relative humidity , respirator , adsorption , chemistry , moisture , activated carbon , water vapor , thermodynamics , environmental science , sorption isotherm , analytical chemistry (journal) , materials science , environmental chemistry , organic chemistry , physics
Objectives In the use of activated carbon beds as adsorbents for various types of organic vapor in respirator gas filters, water adsorption of the bed and test gas humidity are expected to alter the accuracy in the estimation of breakthrough data. There is increasing interest in the effects of moisture on estimation methods, and this study has investigated the effects with actual breakthrough data. Methods We prepared several activated carbon beds preconditioned by equilibration with moisture at different relative humidities (RH=40%‐70%) and a constant temperature of 20°C. Then, we measured breakthrough curves in the early region of breakthrough time for 10 types of organic vapor, and investigated the effects of moisture on estimation using the Wheeler‐ Jonas equation, the simulation software NIOSH Multi‐ Vapor™ 2.2.3, and RBT (Relative Breakthrough Time) proposed by Tanaka et al.Results The Wheeler‐Jonas equation showed good accordance with breakthrough curves at all RH in this study. However, the correlation coefficient decreased gradually with increasing RH regardless of type of organic vapor. Estimation of breakthrough time by MultiVapor showed good accordance with experimental data at RH=50% . In contrast, it showed discordance at high RH (>50%). RBTs reported previously were consistent with experimental data at RH =50%. On the other hand, the values of RBT changed markedly with increasing RH. Conclusions The results of each estimation method showed good accordance with experimental data under comparatively dry conditions (RH≤50%). However, there were discrepancies under high humidified conditions, and further studies are warranted.