From the lab to the field: Recent experiences with nanometals for in situ groundwater remediation

Abstract

Nanometals have received significant attention in recent years due to their ability to rapidly degrade numerous priority source zone contaminants in controlled laboratory studies.  Unfortunately nanoscale metals rapidly grow to micron-sized particles, due magnetic attractive forces, and ultimately settle out of aqueous solutions.  This makes effective in situ delivery to contaminated sediments very difficult.  The addition of polymers on the surface of nanometals significantly improves their stability in aqueous solutions.  This talk will briefly highlight the significant reactivity of nanometals and then discuss a series of 1D column experiments that were conducted to explore the mobility of polymer stabilized nanometals in sand systems.  For the range of conditions tested the nanometals exhibited good mobility in the 10 cm long columns.  The ability of a newly developed numerical model to predict observed behaviour will be presented.   To further explore the utility of nanometals for site remediation the developed numerical simulator was used to model nanometal mobility at the field scale.  The two-dimensional finite element model, which included a heterogeneous permeability field from an actual field site, was used to explore challenges associated with field scale application of nanometals.  Finally the talk will discuss scale up of laboroatory synthesis procedures for a recent field trial and present preliminary results.