Method for obtaining silver nanoparticle concentrations within a porous medium via synchrotron X-ray computed...

Area of Science:

• Environmental Science
• Geochemistry
• Materials Science

Background:

• Understanding nanoparticle fate and transport in subsurface environments is crucial.
• Current methods lack pore-scale quantification capabilities in realistic pore networks.

Purpose of the Study:

• To present the first method for high-resolution quantification of silver nanoparticle (nAg) concentrations within porous media.
• To enable the extraction of nAg concentrations within individual pores in static and quasi-dynamic systems.

Main Methods:

• Utilized absorption-edge synchrotron X-ray computed microtomography (SXCMT).
• Applied an extension of the Beer-Lambert law to convert 3D X-ray mass linear attenuation maps to nAg concentration.
• Investigated factors influencing quantification accuracy, including data acquisition, X-ray refraction, and statistical averaging.

Main Results:

• Developed a method to quantify nAg concentrations at the pore scale with high resolution.
• SXCMT-determined concentrations closely matched ICP analysis results.
• Identified and quantified effects of X-ray refraction and statistical averaging on concentration measurements.

Conclusions:

• The novel SXCMT method provides accurate pore-scale quantification of nAg concentrations in porous media.
• This technique overcomes previous limitations in studying nanoparticle behavior at the pore scale.
• Enables detailed examination of nanoparticle transport properties in controlled laboratory experiments.