Fellow: Jay Thompson
Advisor: Achintya Bezbaruah, Ph.D., Assistant Professor, Department of Civil Engineering, North Dakota State University
Matching Support: Advisor’s salary and tuition waiver (In-kind matching)
Degree Progress: M.S. in Environmental Engineering expected in May 2008. 

Pesticide contamination of groundwater remains an ongoing area of concern. One promising pesticide remediation technology is reductive dechlorination by iron filings or powder.  This technology has been successful in both the lab and field.  However, limitations inherent in this process have limited its use. 

Recent research has shown that nanoscale zero valent iron (NZVI), with its high surface area and reactivity, can overcome many of these limitations.  Although particle properties can vary greatly with synthesis method, typical particles have diameters less than 100 nm.  This property results in extremely high specific surface area, which greatly speeds reactions and can eliminate potentially harmful byproducts.  Additionally, NZVI can be injected directly into an aquifer, eliminating the need for the expensive excavation associated with iron filings.  This research aims to determine the effectiveness of NZVI for the remediation of three commonly used pesticides, atrazine, alachlor and dicamba.

Project objectives:

1. Synthesize and characterize iron nanoparticles.  Characterization techniques include X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and BET surface area analysis.
2. Conduct kinetic degradation trials on the selected pesticides with both nano and micro scale iron.  Compare reaction kinetics and byproducts.
3. Investigate pesticide degradation in environmentally relevant conditions, e.g., column studies, synthetic groundwater, etc.

Progress:

NZVI has been successfully synthesized and characterized.  Cursory screening tests have shown that alachlor is the most susceptible to reductive dechlorination, so full-scale kinetic studies have begun with alachlor.  These studies are nearing completion.  Reaction byproduct identification is ongoing.

Significance:

This research will, for the first time, comprehensively investigate the effect of iron nanoparticles on chloro-s-triazine, chloroacetanilide, and benzoic acid class herbicides.  The results of this research will be useful for the development of a treatment system for herbicide removal from groundwater.  Such a system could remediate herbicides present at a higher concentration than possible with biological processes. 

Presentations:

     Thompson, J., Bezbaruah, A. Chisholm, B. 2007. Laboratory Scale Study to Determine the Effectiveness of Iron Nanoparticles for Selected Pesticide Remediation. American Water Resources Association 2007 Summer Specialty Conference: Emerging Contaminants of Concern in the Environment. Vail, CO. June 25.