Developing Functional Fe(0)-based Nanoparticles for In Situ Degradation of DNAPL Chlorinated
Organic Solvents
Funding Agency
Environmental Protection Agency
Collaborators
Robert Tilton, CMU (CHE)
Sara Majetich, CMU (Physics)
Kris Matyjaszewski, CMU (Chemistry)
Publications
Sarbu, T., Koon-Yee
Lin, John Ell, Daniel J. Siegwart, James Spanswick, and Krzysztof Matyjaszewski
(2004). “Polystyrene with Designed Molecular
Weight Distribution by Atom Transfer Radical Coupling.” Macromolecules 37, 3120-3127.
Liu Y., Majetich,
S. A., Tilton, R. D., Sholl, D. S., Lowry, G.V., (2005). “TCE Dechlorination
Rates, Pathways, and Efficiency of Nanoscale Iron
Particles with Different Properties”, Environ.
Sci. &Technol.
39(5) 1338-1345.
Saleh, N., Traian Sarbu, Kevin Sirk, Gregory V.
Lowry, Krzysztof Matyjaszewski and Robert D. Tilton (2005). “Oil-in-Water
Emulsions Stabilized by Polyelectrolyte-Grafted Nanoparticles.”
Langmuir 21, 9873-9878.
Liu, Y., Hyeok Choi, Sara A. Majetich, Dionysios Dionysiou, Gregory V.
Lowry (2005). TCE Hydrodechlorination
by amorphous monometallic nanoiron.” Chem.
Mat. 17, 5315-5322.
Saleh, N., Phenrat, T., Sirk, K., Dufour, B., Ok, J., Sarbu, T., Matyjaszewski, K.,
Tilton, R., Lowry, G. V. (2005). “Adsorbed Triblock Copolymers Deliver Reactive Iron Nanoparticles to the Oil/Water Interface.” Nano Lett. 5 (12) 2489-2494.
Phenrat, T., Saleh, N.,
Sirk, K., Tilton, R., Lowry, G. V. (2007) Aggregation and Sedimentation of
Aqueous Nanoiron Dispersions. Environ. Sci. Technol.,
41 (1) 284-290.
Saleh, N., Sirk, K.,
Liu, Y., Phenrat, T., Dufour,
B., Matyjaszewski, K., Tilton, R., Lowry, G. V. (2007) “Surface Modifications Enhance Nanoiron Transport and DNAPL Targeting in Saturated Porous
Media.” Environ.
Liu, Y., Lowry, G.V. (2006) “Effect of Particle Age (Fe0 content) and
Solution pH on NZVI Reactivity: H2 Evolution and TCE Dechlorination”. Environ. Sci. Technol., 40 (19) 6085-6090.
Abstract
Groundwater
contamination by chlorinated organic solvents poses a significant health
hazard. Dense Non-Aqueous Phase Liquid
(DNAPL) present at these sites acts as a long-term source, making cleanup
difficult and costly. Nanotechnology has
the potential to reduce the health risk and financial burden of these sites, as
demonstrated by the use of Pd-Fe(0) nanoparticles to degrade dissolved phase TCE in situ. This project will develop “smart” nanoparticles to effectively degrade DNAPLs
in the subsurface, and demonstrate the viability of this approach. The
hypothesis being tested is that the surface of a reactive nanoparticle
can be modified so that it can be transported in water through a porous matrix,
will preferentially partition at a DNAPL-water interface, and degrade DNAPL to
non-toxic products. The primary objective is to significantly improve the
efficiency of in situ groundwater remediation through nanotechnology, by
providing targeted delivery of reactive nanoparticles
directly to the DNAPL-water interface.
The approach is directly inspired by biomedical targeted drug delivery
technologies that efficiently concentrate drug molecules in diseased tissue
sites without wasting drugs (or introducing toxicity) in healthy tissue. Remediation agents introduced into the
subsurface would concentrate at the DNAPL-water interface in response to
designed thermodynamic affinity for the contaminant.
The particular materials proposed are hybrid
nano-structures with targeting provided by tailored
polymers attached to the surface. Nanoparticles consisting of Fe(0)
and Pd-Fe(0) will be synthesized and tested for ability to degrade TCE. The nanoparticle
surfaces will then be modified with amphiphilic
copolymers such that they maintain a stable suspension in water for transport
in a porous matrix, and create an affinity for the water-DNAPL interface. The physical and chemical properties of
particle suspensions will be determined including composite morphology, colloid
stability, polymer layer thickness, interfacial tension, and partitioning
behavior. Mobility, DNAPL targeting
capabilities, and DNAPL degradation rate for the nanoparticles
will be tested in model flow cells representative of subsurface properties at
contaminated sites. The measured DNAPL
degradation efficiency will be compared to those achieved using other treatment
alternatives to determine the potential effectiveness of this approach. The effect of groundwater constituents on the
ability of nanoparticles to transport, target, and
degrade TCE DNAPL will also be investigated.
Feedback from characterization and functionality experiments will help
develop polymer combinations that optimize these properties for their intended
function.
A new class of affinity-targeted nanoscale remediation agents will be developed for
efficient in situ remediation of DNAPL source areas in aquifers. By locating and maintaining reactive nanoparticles at the DANPL-water interface, fewer particles
will be required and more efficient DNAPL remediation is possible relative to
other methods. Moreover, the time to
site closure can be accelerated, significantly lowering the risk to human
health and remediation costs. Additional benefits include the advancement of
nanotechnology through use of synthetic nanoparticles
engineered for specific functions in subsurface environments, and an improved
ability to manipulate the migration of natural colloids. It provides the fundamental knowledge
required to solve other relevant environmental problems with nanotechnology
such as creating subsurface barriers to flow; improving bioremediation
through selective delivery of nutrients; encapsulating contaminants;
selectively mobilizing or sequestering toxic compounds; and, developing “smart
tracers” for in situ subsurface characterization.
The macroscale
problem. Illustration of DNAPL distribution as
residual saturation (sources) and a plume of dissolved contaminants in an
aquifer. Nanotechnology offers the potential
to effectively target the chemical treatment to the residual saturation
zone in situ. Reactive nanoparticles are injected into
the aquifer using a well. The
particles are transported to the contaminant source where they can degrade the
contaminant. Nanoparticles can aggregate (A) and be filtered from solution
via straining (B) or attachment to aquifer grains (C). Methods to target the nanoparticles to
the contaminant (D) could improve the efficiency of the technology.
Greg Lowry Home | Dept. Civil & Env.