Publications by authors named "Eva K Stebel"

Single-solute batch kinetic and isotherm experiments were conducted in Type 1 (18.2 MΩ·cm resistivity) water supplemented with 10 mM carbonate buffer (pH 7.75, 25 °C) for nine drinking water relevant perfluoroalkyl chemicals and three bituminous-coal based granular activated carbons (GACs).

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Multiple non-targeted analysis tools were used to look for a broad range of possible chemical contaminants present in surface and drinking water using liquid chromatography separation and high-resolution mass spectrometry detection, including both quadrupole time of flight (Q-ToF) and Orbitrap instruments. Two chromatographic techniques were evaluated on an LC-Q-ToF with electrospray ionization in both positive and negative modes: (1) the traditionally used reverse phase C18 and (2) the hydrophilic interaction liquid chromatography (HILIC) aimed to capture more polar contaminants that may be present in water. Multiple ionization modes were evaluated with an LC-Orbitrap, including electrospray (ESI) and atmospheric pressure chemical ionization (APCI), also in both positive and negative modes.

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Article Synopsis
  • - The study assessed how selective certain drinking water-related PFAS compounds are for chloride ions using three types of anion exchange resins, focusing on low concentrations relevant to drinking water (≤500 ng/L).
  • - Results showed that most PFAS behaved according to traditional ion exchange principles, with selectivity increasing with both PFAS carbon chain length and chloride concentrations, while maintaining a much higher selectivity than inorganic anions like nitrate.
  • - A competition experiment confirmed that selectivity values for individual PFAS could be used in a multisolute context, paving the way for improved models in water treatment processes involving PFAS.
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A coconut shell (AC1230CX) and a bituminous coal based (F400) granular activated carbon (GAC) were ground with mortar and pestle (MP), a blender, and a bench-scale ball milling unit (BMU). Blender was the most time-efficient for particle size reduction. Four size fractions ranging from 20 × 40 to 200 × 325 were characterized along with the bulk GACs.

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When implementing anion exchange (AEX) for per- and polyfluoroalkyl substances treatment, temporal drinking water quality changes from concurrent inorganic anion (IA) removal can create unintended consequences (e.g., corrosion control impacts).

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Transformation of endocrine active compounds (EACs) by either chlorination (Cl-D) or UV disinfection (UV-D) was studied by field sampling and bench-scale validation studies. Field testing assessed concentration of 13 EACs in effluent at two Chicago area 250 MGD wastewater reclamation plants (WRP) over two years. One WRP uses chlorination/dechlorination while the other employs UV disinfection.

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