Lots to Adsorb: A Survey of PFAS’ Water-Partition Coefficients and Their Relation to Adsorption
Mentor 1
Yin Wang
Mentor 2
Xiaopeng Min
Start Date
16-4-2021 12:00 AM
Description
Perfluoroalkyl Substances (PFAS) are man-made chemicals used in food packaging and housewares for their water-repellent and non-stick properties. As a waste source, they are regarded as an emerging contaminant class known to leach into soil and water sources because of point and non-point source pollution, causing adverse health effects as they accumulate in organisms. As a result, their fate and transport are being heavily studied. Recent PFAS studies have applied the concept of a water-partition coefficient that expresses the affinity of PFAS to host solids in adsorption, which is a type of molecule-to-solid adhesion used to capture contaminants. The coefficients can then be used to fit adsorption data to kinetic and thermodynamic models using different methods, but no one method is ubiquitously used. This research seeks to review the literature on the different methods used to apply the water-partition co-efficient to predict adsorption behavior, as well as their effectiveness. The literature review has indicated that most studies use Langmuir Isotherms, kinetic modeling, or a modification thereof to model adsorption behavior, with the water-partition co-efficient being a variable associated with the initial adsorption and equilibrium stage of Isotherms and an important variable in kinetic model accuracy. The differences in terminology and curve-modeling can be attributed to PFAS only emerging recently in the literature. As a result, consistency in terminologies and more established trends of PFAS adsorption behaviors are required to determine the most effective contexts of each method so that adsorption solids can be better selected for use in capturing free PFAS in the environment which would otherwise adversely affect ecosystems as a contaminant.
Lots to Adsorb: A Survey of PFAS’ Water-Partition Coefficients and Their Relation to Adsorption
Perfluoroalkyl Substances (PFAS) are man-made chemicals used in food packaging and housewares for their water-repellent and non-stick properties. As a waste source, they are regarded as an emerging contaminant class known to leach into soil and water sources because of point and non-point source pollution, causing adverse health effects as they accumulate in organisms. As a result, their fate and transport are being heavily studied. Recent PFAS studies have applied the concept of a water-partition coefficient that expresses the affinity of PFAS to host solids in adsorption, which is a type of molecule-to-solid adhesion used to capture contaminants. The coefficients can then be used to fit adsorption data to kinetic and thermodynamic models using different methods, but no one method is ubiquitously used. This research seeks to review the literature on the different methods used to apply the water-partition co-efficient to predict adsorption behavior, as well as their effectiveness. The literature review has indicated that most studies use Langmuir Isotherms, kinetic modeling, or a modification thereof to model adsorption behavior, with the water-partition co-efficient being a variable associated with the initial adsorption and equilibrium stage of Isotherms and an important variable in kinetic model accuracy. The differences in terminology and curve-modeling can be attributed to PFAS only emerging recently in the literature. As a result, consistency in terminologies and more established trends of PFAS adsorption behaviors are required to determine the most effective contexts of each method so that adsorption solids can be better selected for use in capturing free PFAS in the environment which would otherwise adversely affect ecosystems as a contaminant.
