On nanoscale metallic iron for groundwater remediation.
This communication challenges the concept that nanoscale metallic iron (nano-Fe(0)) is a strong reducing agents for contaminant reductive transformation. It is shown that the inherent relationship between contaminant removal and Fe(0) oxidative dissolution which is conventionally attributed to contaminant reduction by nano-Fe(0) (direct reduction) could equally be attributed to contaminant removal by adsorption and co-precipitation. For reducible contaminants, indirect reduction by adsorbed Fe(II) or adsorbed H produced by corroding iron (indirect reduction) is even a more probable reaction path. As a result, the contaminant removal efficiency is strongly dependent on the extent of iron corrosion which is larger for nano-Fe(0) than for micro-Fe(0) in the short term. However, because of the increased reactivity, nano-Fe(0) will deplete in the short term. No more source of reducing agents (Fe(II), H and H(2)) will be available in the system. Therefore, the efficiency of nano-Fe(0) as a reducing agent for environmental remediation is yet to be demonstrated.
Noubactep
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Angewandte Geologie, Universität Göttingen, Goldschmidtstrasse 3, D-37077 Göttingen, Germany. cnoubac@gwdg.de
Caré
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D052918:Environmental Restoration and Remediation / Q000379:methods*; D007501:Iron / Q000737:chemistry*; D036103:Nanotechnology; D014873:Water Pollutants / Q000302:isolation & purification*
D014873:Water Pollutants; D007501:Iron