Creating environmentally friendly reactive nanoparticles through surface modification

I&EC 155

Gregory V. Lowry, glowry@cmu.edu1, Tanapon Phenrat, tphenrat@andrew.cmu.edu1, Sufia K Kazy, sufia_kazy@yahoo.com2, Pedro J. J. Alvarez2, and Bellina Veronesi, Veronesi.Bellina@epamail.epa.gov3. (1) Department of Civil & Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890, (2) Department of Civil and Environmental Engineering, Rice University, Houston, TX 77251-1892, (3) Neurotoxicology Division-Cellular and Molecular Branch, National Health and Environmental Effects Research Laboratory U.S. Environmental Protection Agency, Mail Drop B105-06, Research Triangle Park, NC 27711
Reactive nanomaterials used for environmental remediation require surface modification to make them mobile in the subsurface. Nanomaterials released into the environment inadvertently without an engineered surface coating will acquire one (e.g. adsorption of natural organic matter). Thus, the chemistry of the surface coating controls a nanoparticle's interactions with mineral surfaces, organic matter, and living organisms, and hence controls its overall fate and potential for exposure and toxicity. This study investigates the effects of polyelectrolyte surface coatings on the mobility of nano-sized Fe0 (NZVI) particles in porous media, and its potential toxicity to microorganisms and neurotoxicity in vitro. NZVI is surface modified with polyaspartate (MW=2000 to 3000 g/mol), characterized in terms of size, adsorbed layer mass and conformation, surface charge, and aggregation. The transport of bare and modified particles is determined in saturated sand columns, the cytotoxicity of bare and surface-modified NZVI to B. subtilis and E. coli is measured in batch systems, and the potential neurotoxicity is assayed in vitro using a number of toxicity end points. In all cases, the presence of a surface coating significantly increased the mobility of the nanomaterials in sand columns, thereby increasing the potential for exposure. However, the surface coatings significantly decreased the toxicity of the NZVI compared to unmodified NZVI, suggesting that surface modification can be used to enhance functionality AND MICROBIAL PARTICIPATION IN THE REMEDIATION PROCESS while decreasing the potential for human or ecotoxicity.
 

Nanotechnology and the Environment: Emphasis on Green Nanotechnology
1:30 PM-5:30 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 231, Oral

Division of Industrial & Engineering Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008