Activation of air-stable zero-valent iron nanoparticles: Comparision of different approaches

Abstract

Nanoscale zero-valent iron (nZVI) particles represent a strong reducing agent which makes them highly promising in the process of degradation of organic compounds such as persistent chlorinated compounds (e.g. chlorinated ethylenes) as well as immobilisation of inorganic pollutants (e.g. hazardous elements). In this contribution, we compare several types of activation procedures to restore the reactivity of air-stable nZVI particles. Different approaches to increase the reactivity of nZVI particles have been tested for hexavalent chromium (Cr(VI)) removal. The study was supplemented by complex characterisation of nZVI particles including electrochemical impedance spectroscopy, X-ray powder diffraction, transmission electron microscopy and specific surface area measurement. Based on experiments of contaminant removal capacity and the characterization of activated nZVI particles, we can conclude that the short-time high-temperature activation process is the most efficient.