We developed electrospun nanofiber mats (ENMs) and their composites with embedded carbon nanotubes (CNTs) for use as passive samplers for various pesticides in air and water.  The majority of the work has been conducted with (i) polymer nanofibers of polyacrylonitrile (PAN), (ii) functionalized PAN composites with embedded carbon nanotubes (with or without surface carboxylic acid groups) and additives that impart surface charge (e.g. tetra-butyl ammonium bromide), and (iii) carbon nanofibers created from carbonization of PAN, using phthalic acid volatilization to create high surface area, macroporous materials.  Various ENMs were tested in sorption kinetic and isotherm experiments toward a diverse suite of pesticides, including atrazine, neonicotinoid insecticides (e.g.imidacloprid, colthianidin), acetochlor, metolachlor, 2,4-D, diuron, and chlorpyrifos.  We generally show that the rate and uptake of pesticides on ENMs can be controlled by tuning nanofiber properties, including nanofiber diameter, the amount and surface chemistry of embedded CNTs, and the presence of surface functional groups integrated into the ENMs via surface-segregating surfactants.  Ultimately, their fast rate and high capacity uptake make these materials ideal for equilibrium passive sampling applications.  For field validation, optimally performing ENMs were deplored in a nearby stream that contained agricultural runoff, revealing good agreement between results obtained with ENM passive sampling and more traditional grab sampling.  In ongoing work, we are testing ENMs in an exposure chamber with an influx of pesticides volatilized in air and measuring these materials ability to also perform as passive samplers in air.  Collectively this work highlights the promise of electrospun nanofiber mats as a next generation, multi-media passive sampling technology.

Passive sampling of pesticides in air and water using electrospun nanofiber mats

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.