Chapter 18 - Physicochemistry of Polyelectrolyte Coatings that Increase Stability, Mobility, and Contaminant Specificity of Reactive Nanoparticles Used for Groundwater Remediation

Abstract

This chapter reveals that the novel reactive nanomaterials offer the potential for efficient targeted delivery of remedial agents to subsurface contaminants such as chlorinated solvents and heavy metals. The primary challenge to their application is to overcome rapid aggregation and deposition of these nanomaterials in water-saturated porous media, and to improve the efficiency by increasing the specificity of the nanoparticles for specific subsurface contaminants. The amphiphilic nature of some coatings provides the particles specificity for the dense nonaqueous phase liquid (DNAPL)/water interface; whereas other coatings use ligands to specifically sequester heavy metals or hydrophobic nanoparticles to selectively adsorb very hydrophobic organic contaminants. This chapter describes the state-of-the art in polymeric surface modification for reactive nanoparticles used for in situ groundwater remediation, explains the fundamental physieochemical processes by which polyelectrolyte surface modification and functionalization inhibit aggregation and deposition, and increases mobility in the subsurface. It also describes the methods used for targeting specific subsurface contaminants.