Tunable synthesis and immobilization of zero-valent iron nanoparticles for environmental applications.

Zero-valent iron (ZVI) nanoparticles were synthesized and immobilized using supported polyelectrolyte multilayers as nanoreactors. The ZVI nanoparticles so produced were found to exhibit superior reactivity with respect to chemical reduction and deactivation of trichloroethylene, a compound representative of a major class of chlorinated organic contaminants. Manipulation of polyelectrolyte multilayer architectures and synthesis conditions rendered the properties and reactivities of the resulting ZVI nanoparticles readily tunable. In particular, the reactivity of ZVI nanoparticles appears to depend strongly on certain architectural features of the polyelectrolyte multilayer that are regulated by the pH of the assembly media. The results suggest significant potential for use of the polyelectrolyte multilayer approach to fabricate reactive iron nanoparticles for a broad range of environmental applications, and provide a scientific basis for material design and optimization.