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POLYMERIC NANOFIBER-CARBON NANOTUBE COMPOSITE MATS AS FAST-EQUILIBRIUM PASSIVE SAMPLERS FOR POLAR ORGANIC CONTAMINANTS
Qian, J., A. Martinez, R.F. Marek, M.R. Nagorzanski, H. Zhi, E.T. Furlong, D.W. Kolpin, et al.
Environmental Science & Technology 54(11):6703-6712 (2020)
To improve the performance of polymeric electrospun nanofiber mats (ENMs) for equilibrium passive sampling applications in water, two types of multiwalled carbon nanotubes (CNTs) – with and without surface carboxyl groups – were integrated into polyacrylonitrile (PAN) and polystyrene (PS) ENMs. For 11 polar and moderately hydrophobic compounds, 90% of equilibrium uptake was achieved in under 0.8 days (Ii>t90% values) in non-mixed ENM-CNT systems. Sorption capacity of ENM-CNTs was between 2- and 50-fold greater than pure polymer ENMs, with equilibrium partition coefficients ranging from 1.4 to 3.1 log units (L/kg) depending on polymer type (hydrophilic PAN or hydrophobic PS), CNT loading, and CNT type. During field deployment at Muddy Creek in North Liberty, Iowa, optimal ENM-CNTs (PAN with 20 wt% carboxylated CNTs) yielded atrazine concentrations in surface water with a 40% difference relative to analysis of a same-day grab sample. A mean percent difference of 30 (±20)% was observed when comparing ENM-CNT sampler results to grab sample data collected within one week of deployment.
Environmental Science & Technology 54(11):6703-6712 (2020)
To improve the performance of polymeric electrospun nanofiber mats (ENMs) for equilibrium passive sampling applications in water, two types of multiwalled carbon nanotubes (CNTs) – with and without surface carboxyl groups – were integrated into polyacrylonitrile (PAN) and polystyrene (PS) ENMs. For 11 polar and moderately hydrophobic compounds, 90% of equilibrium uptake was achieved in under 0.8 days (Ii>t90% values) in non-mixed ENM-CNT systems. Sorption capacity of ENM-CNTs was between 2- and 50-fold greater than pure polymer ENMs, with equilibrium partition coefficients ranging from 1.4 to 3.1 log units (L/kg) depending on polymer type (hydrophilic PAN or hydrophobic PS), CNT loading, and CNT type. During field deployment at Muddy Creek in North Liberty, Iowa, optimal ENM-CNTs (PAN with 20 wt% carboxylated CNTs) yielded atrazine concentrations in surface water with a 40% difference relative to analysis of a same-day grab sample. A mean percent difference of 30 (±20)% was observed when comparing ENM-CNT sampler results to grab sample data collected within one week of deployment.
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