Wettability changes in trichloroethylene-contaminated sandstone

Area of Science:

• Environmental Science
• Geochemistry
• Material Science

Background:

• Chlorinated solvent nonaqueous-phase liquids (NAPLs) are typically assumed to be nonwetting in water-saturated porous media.
• The wetting behavior of industrially used solvents, such as trichloroethylene (TCE), may differ from laboratory-grade equivalents.

Purpose of the Study:

• To investigate the wetting characteristics of industrially used TCE on porous media.
• To determine if used TCE alters the wettability of quartz and sandstone compared to laboratory-grade TCE.

Main Methods:

• Contact angle measurements were performed on quartz slides exposed to used TCE.
• Wettability of sandstone cores was assessed using the Amott test.
• Laboratory-grade TCE and synthesized mixtures were used for comparison.

Main Results:

• Used TCE significantly altered the wettability of quartz slides, inducing contact angle changes up to 170 degrees.
• Sandstone cores exposed to used TCE exhibited a shift towards neutral wetting.
• Laboratory-grade TCE and synthesized mixtures caused contact angle changes but did not alter overall wettability.
• Increased exposure duration to solvents impacted measured contact angles.

Conclusions:

• Industrially used TCE can render initially water-wet porous media nonwetting or neutrally wetting.
• The presence of industrial contaminants in TCE is crucial in altering its wetting behavior.
• Solvent exposure duration is a significant factor influencing wettability measurements.