Remediation of soils and groundwater contaminated with toxic metals and metalloids has been a major environmental challenge for decades. Yet, cost-effective and sustainable in situ remediation technologies remain lacking. Through more than a decade of intensive research, the Auburn University research team has developed a strategy to synthesize highly stable, soil-dispersible nanoparticles using low-cost and “green” polysaccharides, such as starch and carboxymethyl cellulose (CMC), as a stabilizer. The stabilizers can facilitate controlling the size, delivery and transport of the nanoparticles. This presentation will introduce the concept of in situ immobilization of metals/metalloids in soil and groundwater using various stabilized nanoparticles, and overview the effectiveness of the stabilized nanoparticles, including zero-valent iron (ZVI) for reductive immobilization of U(VI), Tc(VII), and Cr(VI), FeS for sorption of Hg(II), Pb(II) and Cd(II), and Fe-Mn binary oxides for As(V) and As(III). Lab and field-scale experiments demonstrated that these nanoparticles offer some unprecedented advantages over traditional aggregated particles, including: 1) they can be delivered and dispersed in various soils and attack contaminant plumes deep in aquifers, and 2) they offer strong affinity and high sorption capacity toward the target metals/metalloids. We also characterized the environmental fate and transport of these stabilized nanoparticles in the subsurface. While the application of the stabilizers facilitated the soil deliverability and dispersion of the nanoparticles, once delivered, the nanoparticles will remain in the targeted domain under typical natural soil and groundwater conditions, serving as a long-term sink for the contaminants. The in situ immobilization technology holds the potential to greatly advance the conventional practices in remediation of contaminated soil and groundwater.

Development and applications of stabilized nanoparticles for in situ immobilization of metals/metalloids in soil and groundwater

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.