Superfund Research Program
Green and Sustainable in situ Remediation of Heavy Metals Contaminated Soils and Aqueous Systems
Project Leader: Nadia Adam
Grant Number: R43ES031892
Funding Period: Phase I: September 2020 - March 2023
This SBIR phase I project will demonstrate the feasibility of in situ remediation of heavy metals Pb(II), Cd(II), Cu(II), Hg(II), Ni(II), Cr(VI), As(V), and Sb(V) contaminated soils and aqueous systems using novel green Fe-P nanoparticles synthesized using a proprietary (US Patent Pending) process. The widespread contamination of soils, surface waters, and ground water with heavy metal(loid)s currently represents one of the most severe environmental problems that can seriously affect environmental quality and human health. The project is particularly pertinent to contaminated soils, sediments and groundwater such as for the USS lead superfund site. Current and ongoing clean up of the USS lead superfund site located in East Chicago and Indiana is via direct excavation of contaminated soils to landfills costing in excess of 100 million dollars. The disturbance to the environment and workers exposure to toxic metals is much higher during the excavation, removal, and storage of contaminated soil to landfills w/o solving the contamination problem. Thus next generation, green, and cost-effective in situ remediation approaches with a clear impact on human health are needed. As part of the proposed SBIR phase I work, the research team is determining optimal Fe-P dosage to achieve remediation efficacy in soil and aqueous systems to meet EPA mandated MCL for respective metalloids and show the efficacy of this approach in real world samples of contaminated ground water. Unique advantages of the research team's technology include: 1) The proposed Fe-P nanoparticles unlike current Fe based nanoparticles are based on a new paradigm and are effective in remediating all trace metals in contaminated soils and groundwater; 2) while being an order of magnitude more cost- effective than current state of the art; it's synthesis is simple using a green process. They are similar to natural minerals found in soils (unlike nanozerovalent Fe) thus there is no concern with bioaccumulation or other adverse effects on human health; and 3) Fe-P nanoparticles utilize dual Fe-OH2+ and O-PO43- functional groups enabling permanent binding of cationic and anionic metalloids enabling a one step solution to mixed metal contamination (as is often the case). Unlike nZVFe and other iron based nanoparticles, they do not aggregate or need external stabilizers and do not corrode. This would guarantee stability compared to the current state of the art where immobilized phases are not very stable with low dissociation energies. Finally, reductive immobilization of Cr(VI) to Cr(III) and As(V) to As(III) is not uniformly helpful because while the reduced Cr(III) is less toxic than Cr(VI); the reduced As(III) is much more toxic than As(V) form.