Related Experiment Video
Updated: Feb 3, 2026
18:57
Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
47.4K
Comprehensive retention model for PFAS transport in subsurface systems.
Mark L Brusseau1, Ni Yan2, Sarah Van Glubt3
1Soil, Water, and Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States; Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, AZ, 85721, United States.
Water Research
|October 22, 2018
Summary
Adsorption at fluid-fluid interfaces significantly retains per- and polyfluoroalkyl substances (PFAS) in unsaturated soils. This interfacial adsorption is a key factor in PFAS transport and fate, influencing their environmental behavior in source zones.
Area of Science:
- Environmental Chemistry
- Geochemistry
- Environmental Engineering
Background:
- Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants.
- Understanding PFAS retention mechanisms in source zones is crucial for effective remediation.
- Fluid-fluid interfaces play a role in contaminant transport, especially in variably saturated media.
Purpose of the Study:
- To develop and validate a comprehensive compartment model for PFAS retention in source zones.
- To investigate the impact of air-water and decane-water interfacial adsorption on PFAS transport.
- To quantify the contribution of interfacial adsorption to overall PFAS retention.
Main Methods:
- Miscible-displacement experiments using quartz sand and soil.
- Transport experiments under saturated and unsaturated conditions.
- Utilized perfluorooctanesulfonic acid (PFOS) as the model PFAS.
- Developed methods for parameterizing the compartment model.
Main Results:
- Unsaturated conditions led to significantly greater PFOS retardation (delayed arrival) compared to saturated conditions.
- Air-water interfacial adsorption accounted for over 80% of PFOS retention in sand and 32% in soil.
- Decane-water interfacial adsorption contributed over 70% to PFOS retention in sand.
- Predicted retardation factors closely matched measured values, validating the model.
Conclusions:
- Adsorption at fluid-fluid interfaces is a significant retention process for PFAS in variably saturated porous media.
- The developed compartment model adequately represents key PFAS retention processes.
- Interfacial adsorption must be considered in characterizing PFAS transport and fate in source zones.
More Related Videos
12:18Pore-scale Imaging and Characterization of Hydrocarbon Reservoir Rock Wettability at Subsurface Conditions Using X-ray Microtomography
Published on: October 21, 2018
14.6K
14:25Window on a Microworld: Simple Microfluidic Systems for Studying Microbial Transport in Porous Media
Published on: May 3, 2010
11.3K
Related Concept Videos
01:20Gas Exchange and Transport
76.9K
Gas exchange, the intake of molecular oxygen (O2) from the environment and the outflow of carbon dioxide (CO2) into the environment, is necessary for cellular function. Gas exchange during respiration occurs largely via the movement of gas molecules along pressure gradients. Gas travels from areas of higher partial pressure to areas of lower partial pressure. In mammals, gas exchange occurs in the alveoli of the lungs, which are adjacent to capillaries and share a membrane with them.
76.9K
01:19Facilitated Transport
148.1K
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a...
148.1K
01:47Primary Active Transport
198.5K
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction...
198.5K
01:55Secondary Active Transport
137.9K
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
137.9K
02:22Regulated mRNA Transport
7.0K
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing...
7.0K
02:02Phloem and Sugar Transport
40.0K
Like many living organisms, plants have tissues that specialize in specific plant functions. For example, shoots are well adapted to rapid growth, while roots are structured to acquire resources efficiently. However, sugar production is primarily restricted to the photosynthetic cells that reside in the leaves of angiosperm plants. Sugar and other resources are transported from photosynthetic tissues to other specialized tissues by a process called translocation.
40.0K