Highly tunable fluorescent core-shell particles for environmental release simulation and tracking applications
Inventors
Assignees
US Environmental Protection Agency
Publication Number
US-10941057-B2
Publication Date
2021-03-09
Expiration Date
2038-06-28
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Abstract
A particle for emulating pollutant tracking in water has a florescent core. A semitransparent shell is formed around the florescent core.
Core Innovation
The invention is a particle for emulating pollutant tracking in water that comprises a fluorescent core surrounded by a semitransparent shell. This core-shell particle is designed to mimic the transport properties of environmental contaminants such as oil and chemical spills, addressing the difficulty in developing accurate simulants for environmental release simulation and tracking.
The problem being solved is that current materials used to track or emulate crude oil movement, such as coffee beans, peat moss, and wood chips, do not adequately represent actual crude oil behavior, especially surface and sub-surface transport of oil droplets. Traditional tracers like fluorescent dyes also rapidly dilute, have low absorption rates, and degrade quickly under sunlight, limiting their usefulness for tracking contaminants in water.
The invention overcomes these limitations by providing tunable core-shell particles with fluorescent cores formed by electrospray generation, producing monodisperse particles with controlled sizes from nanometer to micrometer scales. The semitransparent shell, formed by condensational growth using biodegradable materials like plant or animal waxes, allows visibility of the fluorescent core and can be tailored to have specific surface properties to mimic pollutant behavior such as floating, sinking, or adhesion.
Claims Coverage
The independent claims disclose methods of forming particles comprising fluorescent cores and biodegradable semitransparent shells designed to emulate pollutant movement in water. The claims emphasize the processes and materials for the core and shell formation, as well as tailoring physical and surface properties to simulate pollutant transport.
Formation of fluorescent cores by electrospray generation
This feature covers producing fluorescent cores by spraying a fluorescent dye through at least one spray nozzle into an electrospray chamber to create monodisperse fluorescent cores, allowing control over particle size and charge for self-dispersion.
Formation of biodegradable semitransparent shells around fluorescent cores
This feature describes forming semitransparent shells by applying a vapor air mixture coating the fluorescent cores, where the shell materials are biodegradable, such as plant or animal waxes, applied via a furnace process with a holder containing the shell material and cores.
Tailoring shell properties to emulate pollutant movement and interactions
This feature includes selecting the vapor air mixture and shell material to match the movement properties of the desired pollutant in water and to control particle-particle interactions, such as promoting attraction to form cohesive units or repelling to mimic individual droplets.
The claims collectively disclose a method to produce fluorescent core-shell particles with controlled size, biodegradable shells formed by condensational growth, and customizable surface chemistry to simulate pollutant transport and interactions in water environments.
Stated Advantages
The core-shell particles provide improved emulation of environmental contaminant transport properties compared to traditional materials and tracers.
Tunable size and surface behavior allow for modeling a range of pollutant behaviors including floating, sinking, adhesion, and repulsion.
The biodegradable nature of the particles reduces potential environmental impact during and after their use.
The particles have strong fluorescence, enabling detection in both concentrated and diluted conditions.
The electrospray generation process allows for high-volume, continuous, and scalable production of uniform particles.
Documented Applications
Use as simulants and tracers for environmental release simulation and tracking of oil and chemical spills in water, including open water environments such as oceans and rivers.
Modeling pollutant transport in complex environmental media such as soils and sediments.
Emergency response training exercises where oil simulants visible under fluorescence are needed to trace spill movement.
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