Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 3, 2003
Publication Date: September 20, 2003
Citation: Allaire, S.E., Yates, S.R., Ernst, F., Papiernik, S.K. 2003. Gas phase sorption-desorption of propargyl bromide and 1,3dichloropropene on plastic materials. Journal of Environmental Quality. 32:1915-1921. Interpretive Summary: The effect of adsorption of chemicals onto materials used to build experimental equipment, such as chambers, hasn't been studied in detail. Adsorption to experimental equipment can significantly affect the experimental results and obscure the true transport behavior. Materials should be used that minimize adsorption so that confounding effects are eliminated. Information exists on fumigant sorption to agricultural plastic films and methyl bromide sorption to Teflon, but there is limited information on vapor sorption-desorption of fumigants to other materials commonly used in laboratory equipment. The objective of this study was to provide information on vapor sorption-desorption of two fumigants (propargyl bromide and 1,3-dichloropropene) onto several different materials, including: stainless steel, teflon PTFE-FEP, flexible polyvinyl chloride, acrylic, nylon 66, low density polyethylene, vinyl (Tygon R3603), silicone, and polyurethane foam. These materials are commonly used to carry, sample, store, or build experimental equipment for the study of gases.
Technical Abstract: The goal of this research was to provide information for choosing appropriate materials for studying gas-phase concentration of propargyl bromide (3BP) and 1,3-dichloropropene (1,3-D) in laboratory experiments. Several materials were tested and found to sorb both gas-phase chemicals in the following order: Stainless steel (SS)< Teflon PTFE-FEP flexible polyvinyl chloride (PVC) acrylic < nylon 66 < Low density polyethylene (PE) < vinyl (Tygon R3603) silicone < polyurethane foam (PUF). Sorption of SS was insignificant and PUF sorbed as much as 3100 mg g-1 of 3BP and 740 mg g-1 of 1,3-D. For the other materials, linear sorption coefficients (Kd) for 3BP ranged from 3.0 cm3 g-1 for PVC to 215 cm3 g-1 for silicone. Freudlich sorption coefficients for 1,3-D ranged from 11.5 to 371 cm3 g-1. First-order desorption rate constants in an open system ranged from 0.05 to 1.38 hr-1 for 3BP and from 0.07 to 1.73 hr-1 for 1,3-D. In a closed system, less than 2 percent of sorbed fumigant desorbed from vinyl while up to 99 percent desorbed from PVC within 24 hours when equilibrated at the highest headspace concentration. Sorption of both fumigants was linearly related to the square root of time except for vinyl and silicone. This may indicate non-fickian diffusion of fumigant into the polymer matrix. Vinyl, silicone, PE, and PUF should be avoided for quantitative study of organic gases, except possibly as a trapping medium. Use of PTFE, PVC, acrylic and nylon may require correction for sorption-desorption and diffusion.