Novel Methodology for the Estimation of Chemical Warfare Agent Mass Transport Dynamics, Part I: Evaporation

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• 作者：Matthew P. Willis ; Brent A. Mantooth ; Teri A. Lalain
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：538-545
• 全文大小：460K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1932-7455

文摘

A novel contact angle experimental and computational methodology has been developed to estimate mass transport parameters for the evaporation of water and bis(2-chloroethyl) sulfide (distilled mustard, known as the chemical warfare agent HD) on homogeneous, impermeable, substrates of interest. The model uses a finite element technique to simulate the evaporation of a liquid droplet into air. A regression technique is applied to experimental contact angle data to determine the temperature-dependent mass transport parameters (i.e., the diffusivity of the agent in air). The technique predicted the diffusion coefficient for water in air within 1% at 40 掳C. The methodology was used to evaluate the evaporation of HD into air at several temperatures, which may be used to develop accurate predictions for vapor emission hazards due to vapor-phase HD. Evaporation of liquid HD generates potential hazards to unprotected personnel. Modeling this process on nonsorptive substrates is the first step toward enable modeling contamination on absorptive substrates. The novel methodology can be applied to other chemicals and therefore may be implemented as a preliminary assessment of the chemicals鈥?ability to evaporate, which can generate the potential for a chemical vapor hazard. The physics-based models, combined with the generated physical parameter values, enable the prediction of vapor emission hazards from the substrate. The application of this model is intended to simulate chemical warfare agents; however, it is applicable to any liquid on a surface.