SYNTHESIZING NANOSCALE IRON PARTICLES FOR RAPID AND COMPLETE DECHLORINATION OF TCE AND PCBS

Transformation of halogenated organic compounds (HOCs) by zero-valent iron represents one of the latest innovative technologies for environm ental remediation. For example, iron can be used to construct a reacti ve wall in the path of a contaminated groundwater plume to degrade HOC s. In this paper, an efficient method of synthesizing nanoscale (1-100 nm) iron and palladized iron particles is presented. Nanoscale partic les are characterized by high surface area to volume ratios and high r eactivities. BET specific surface area of the synthesized metal partic les is 33.5 m(2)/g. In comparison, a commercially available Fe powder (<10 mu m) has a specific surface area of just 0.9 m(2)/g. Batch studi es demonstrated that these nanoscale particles can quickly and complet ely dechlorinate several chlorinated aliphatic compounds and a mixture of PCBs at relatively low metal to solution ratio (2-5 g/100 mL). Sur face-area-normalized rate constants (K-SA) are calculated to be 10-100 times higher than those of commercially available iron particles. The approach presented offers unique opportunities for both fundamental r esearch and technological applications of zero-valent metals. For exam ple, a potential application of the nanoscale particles is to inject t he metal particles directly into contaminated aquifers instead of buil ding iron walls.