Follow NEMC
 |
 |
 |
Mil-53(Al) as a Sorbent for Large Volume Air-Sampler for Chemical Warfare Agents
Oral Presentation
Prepared by B. Williamson1, C. Baker2, K. Favela3, J. Jones4
1 - Southwest Research Institute, 6220 Culebra Rd, San Antonio, Texas, 78228
2 - Southwest Research Institute, 6220 Culebra Rd, San Antonio , Texas, 78228
3 - Southwest Research Institute, 6220 Culebra Rd, San Antonio , Texas, 78228
4 - Southwest Research Institute, 6220 Culebra Rd, San Antonio , Texas, 78228
Contact Information: bwilliamson@swri.edu; 210-522-2187
ABSTRACT
Mil-53(Al) (Basolite® A100) is a highly porous, metal organic framework (MOF) material that has favorable properties for the collection and preservation of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), including high capacity and resistance to water-effects. In order to maximize the high capacity potential of this sorbent, it was coated onto Duocel® that is 80 pores per inch (ppi) reticulated vitreous carbon (RVC) with an open, porous structure allowing a high sampling rate. The combination of the high-capacity sorbent and cross-sectional area of the substrate facilitates much more rapid collection and concentration of chemicals over traditional sampling techniques such as XAD and is especially important for trace-level substances which may be forensically valuable. Small RVC coupons were coated with approximately 8.9 mg of Mil-53(Al) and four parameters (temperature, relative humidity, flow rate, collection volume) were systematically varied to evaluate performance under a range of conditions. All testing was conducted using 16 CWA-related compounds: N,N-diethyl aniline (DEA), 2-chloroethyl ethyl sulfide (CEES), diethyl ethyl phosphonate (DEEP), 2-chloroethyl phenyl sulfide (CEPS), 1,4-dithiane (DITH), O,O'-diethyl methylphosphonothioate (DEMPT), diethyl phosphite (DEP), diisopropyl fluorophosphates (DIFP), 1,4-thioxane (THX), dimethyl phosphite (DMHP), triethyl phosphate (TEP), bis(2-chloroethyl) sulfide (HD), O-isopropyl methylphosphonofluoridate (GB), 3,3-dimethylbutan-2-yl methylphosphonofluoridate (GD), diisopropyl methylphosphonate (DIMP) and dimethyl methylphospnonate (DMMP). Small RVC coupon recoveries for the 16 compounds averaged over all conditions were greater than 70% with the exception of GB (53%) and DMHP (35%). Furthermore, RSD over all conditions was less than 20% with the exception of DMHP (46%). This indicates the sorbent-coated RVC is very robust over conditions that are likely to be encountered in a field-setting. In general, the absorption affinity for the sulfur–containing compounds (THX, CEES, DEMPT, DITH) was lower than for the other classes of compounds tested. Preservation of the compounds on the Mil-53(Al)-coated RVC was tested at 0, 1, 3, 7, 14, 28, and 30 days post-collection. Percent loss over the 30-day period was less than 11% for each compound with the exceptions of DMHP (23%), GB (20%), and GD (20%), demonstrating adequate preservation for a minimum of 1 month. Finally, RVC large coupons containing approximately 30 mg of Mil-53(Al) sorbent were tested to demonstrate the potential to scale-up the sorbent/RVC system without sacrificing performance. In most instances, the large coupon performance was superior to that of the smaller coupons and traditional XAD tubes. Performance increase was especially clear for DMHP which improved significantly in both recovery (93%) and variability (6% RSD) over the small RVC coupons and XAD. The overall performance of the Mil-53(Al)/RVC air collection system indicates very efficient concentration of trace TIC and CWA substances is achievable via rapid, large volume sampling.
Oral Presentation
Prepared by B. Williamson1, C. Baker2, K. Favela3, J. Jones4
1 - Southwest Research Institute, 6220 Culebra Rd, San Antonio, Texas, 78228
2 - Southwest Research Institute, 6220 Culebra Rd, San Antonio , Texas, 78228
3 - Southwest Research Institute, 6220 Culebra Rd, San Antonio , Texas, 78228
4 - Southwest Research Institute, 6220 Culebra Rd, San Antonio , Texas, 78228
Contact Information: bwilliamson@swri.edu; 210-522-2187
ABSTRACT
Mil-53(Al) (Basolite® A100) is a highly porous, metal organic framework (MOF) material that has favorable properties for the collection and preservation of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), including high capacity and resistance to water-effects. In order to maximize the high capacity potential of this sorbent, it was coated onto Duocel® that is 80 pores per inch (ppi) reticulated vitreous carbon (RVC) with an open, porous structure allowing a high sampling rate. The combination of the high-capacity sorbent and cross-sectional area of the substrate facilitates much more rapid collection and concentration of chemicals over traditional sampling techniques such as XAD and is especially important for trace-level substances which may be forensically valuable. Small RVC coupons were coated with approximately 8.9 mg of Mil-53(Al) and four parameters (temperature, relative humidity, flow rate, collection volume) were systematically varied to evaluate performance under a range of conditions. All testing was conducted using 16 CWA-related compounds: N,N-diethyl aniline (DEA), 2-chloroethyl ethyl sulfide (CEES), diethyl ethyl phosphonate (DEEP), 2-chloroethyl phenyl sulfide (CEPS), 1,4-dithiane (DITH), O,O'-diethyl methylphosphonothioate (DEMPT), diethyl phosphite (DEP), diisopropyl fluorophosphates (DIFP), 1,4-thioxane (THX), dimethyl phosphite (DMHP), triethyl phosphate (TEP), bis(2-chloroethyl) sulfide (HD), O-isopropyl methylphosphonofluoridate (GB), 3,3-dimethylbutan-2-yl methylphosphonofluoridate (GD), diisopropyl methylphosphonate (DIMP) and dimethyl methylphospnonate (DMMP). Small RVC coupon recoveries for the 16 compounds averaged over all conditions were greater than 70% with the exception of GB (53%) and DMHP (35%). Furthermore, RSD over all conditions was less than 20% with the exception of DMHP (46%). This indicates the sorbent-coated RVC is very robust over conditions that are likely to be encountered in a field-setting. In general, the absorption affinity for the sulfur–containing compounds (THX, CEES, DEMPT, DITH) was lower than for the other classes of compounds tested. Preservation of the compounds on the Mil-53(Al)-coated RVC was tested at 0, 1, 3, 7, 14, 28, and 30 days post-collection. Percent loss over the 30-day period was less than 11% for each compound with the exceptions of DMHP (23%), GB (20%), and GD (20%), demonstrating adequate preservation for a minimum of 1 month. Finally, RVC large coupons containing approximately 30 mg of Mil-53(Al) sorbent were tested to demonstrate the potential to scale-up the sorbent/RVC system without sacrificing performance. In most instances, the large coupon performance was superior to that of the smaller coupons and traditional XAD tubes. Performance increase was especially clear for DMHP which improved significantly in both recovery (93%) and variability (6% RSD) over the small RVC coupons and XAD. The overall performance of the Mil-53(Al)/RVC air collection system indicates very efficient concentration of trace TIC and CWA substances is achievable via rapid, large volume sampling.