Abstract
Chlorinated aliphatic compounds such as trichloroethylene are main contaminants of groundwater, and the dechlorination technique using iron powder as metallic reduction agents was investigated as a remediation technology for such contaminations. As for the iron powder obtained from industrial processes or waste, as well as the dechlorination rate constants of chlorinated aliphatics could be obtained through laboratory experiments, as well as the data on specific surface area and iron content. Furthermore, X-ray photoelectron spectroscopy (XPS) was used for measuring the fraction of zero-valent iron, divalent iron, and trivalent iron at the surface of iron powder, and for measuring the distribution of iron species along the depth direction by XPS after each etching time. The rate constant of a pseudo-first-ordered reaction can be ranked using the index of reaction area, which is determined by multiplying specific surface area by the mean zero-valent iron fraction measured by XPS.
