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An Electrochemical Investigation of the Enhanced Reactivity of Clays in Contact with Iron Metal


EMSL Project ID
2247

Abstract

Clays and iron metal are each independently capable of reducing a range of contaminants in aqueous solutions. There is a synergistic effect on the rate of reduction, however, when clays are in contact with iron metal. One mechanism proposed to explain this synergistic effect is that the dissolution of the clays in solution leads to the creation of protons and/or ions that increase the rate of corrosion of the iron metal to Fe(II); the Fe(II) that is adsorbed on or intercalated into the clay is an especially strong reductant and is responsible for the increased rate of reduction . The goal of our collaboration is to understand the detailed mechanism whereby clays interact with iron metal to produce a stronger reductant. Specifically, we will address the following questions: (i) Is Fe(II) from the electrochemical corrosion of iron metal responsible for the increased reactivity of clays in contact with iron metal?; (ii) Where in the clay film is the Fe(II) from the iron corrosion located ?; (iii) What is the mobility of the Fe(II) in the clay?; (iv) Does the clay accelerate the corrosion of iron or serve only as an Fe(II) adsorber?; (v) What is the role of the iron metal, i.e., is iron metal necessary or is Fe(II) dissolving from minerals (e.g. magnetite) sufficient? We propose to use clay-modified iron electrodes (CMIEs) in combination with Mvssbauer and FTIR spectroscopy to answer the above questions. This project requires the collaboration of Jim Amonette at EMSL because of his experience in using clays for contaminant reduction and his expertise in clay processing. The collaboration also makes it possible to use equipment at EMSL that is not available at Lewis & Clark College, specifically the FTIR and Mossbauer spectrometers, to characterize the clays after they have been in contact with the iron electrodes.

Project Details

Project type
Exploratory Research
Start Date
2001-05-08
End Date
2003-05-18
Status
Closed

Team

Principal Investigator

Barbara Balko
Institution
Lewis and Clark College

Related Publications

An Electrochemical Investigation of the Enhanced Reactivity of Clays in Contact with Iron Metal