Evaluate Injection of Zero Valent Iron (PNNL Scope# 488994: Oostrom Fluor Daniel Hanford)
EMSL Project ID
14892
Abstract
We propose a series of intermediate-scale column and flow cell experiments using micrometer-scale particles. The micrometer particles used in the experiments are S-3700 Fe0 colloids with a diameter of 2 +/- 1 mm (International Speciality Products, Wayne, N.J.) and H-200 Special Zerovalent Iron with a diameter of 43 +/- 5 mm (ARS Technologies, New Brunswick, NJ). The S-3700 particles have been extensively tested in both batch and column experiments (Cantrell et al, 1997; Cantrell and Kaplan, 1997; Kaplan et al., 1994). These studies indicated that S-3700 colloid suspensions mixed with an anionic surfactant (Aerosol, Sigma Chemical Co.) and a synthetic high molecular weight polymer (vinyl polymer, VP), greatly increased the mobility of the colloidal zerovalent iron suspensions in porous media. The polymer acted as a shear-thinning fluid. In the proposed experiments, the S-3700 micrometer suspensions will contain both the surfactant and the polymer. The H-200 Iron from ARS Technologies has been successfully applied at many sites (see http://zerovalentiron.com). The removal of particles from a colloid suspension with micrometer-scale Fe0 particles can potentially occur through mechanical sieving, gravitational settling, and adsorption onto the surfaces of the porous media. Cantrell and Kaplan (1997) determined that gravitational settling was the most important mechanism in highly permeable laboratory sands.Zerovalent nanoparticles were also considered for this study. Unfortunately, the level of knowledge regarding injection of nanometer particle suspensions in porous media is not as developed as for the micrometer particles (e.g., Schrick et al., 2004). Detailed preliminary batch and small-column displacement studies need to be conducted first before a nanometer suspension with potential chemical enhancements can be recommended for field application. These initial studies are not included in the scope of this work.
The proposed work consists of several column and two intermediate-scale flow cell experiments. The column experiments will be conducted to determine the optimum combination of zerovalent micrometer iron, surfactant, and polymer concentration, injection rate and duration. The flow cell experiments test the zerovalent iron suspension and settling behavior in a heterogeneous system in two- and three dimensions. These studies will also provide needed information of density-dependent flow phenomena as the denser-than-water iron colloid suspension are injected. The experimental work will be conducted in the Environmental Molecular Sciences Laboratory at PNNL.
Project Details
Project type
Exploratory Research
Start Date
2005-04-15
End Date
2007-03-22
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Truex MJ, T Macbeth, VR Vermeul, BG Fritz, DP Mendoza, RD Mackley, M Oostrom, TW Wietsma, G Sandberg, T Powell, J powers, E Pitre, MM Michalsen, S Ballock-Dixon, and L Zhong. 2010. "Demonstration of Combined Zero-Valent Iron and Electrical Resistance Heating for In Situ TCE Remediation." PNNL-SA-76701, Pacific Northwest National Laboratory, Richland, WA. [Unpublished]
Truex MJ, VR Vermeul, DP Mendoza, BG Fritz, RD Mackley, M Oostrom, TW Wietsma, and T Macbeth. 2011. "Injection of Zero Valent Iron into an Unconfined Aquifer Using Shear-Thinning Fluids." Ground Water Monitoring and Remediation 31(1):50-58.