Synthesis of reactive nanoscale zero valent iron using rectorite supports and its application for Orange II removal

The nanoscale zero valent iron-rectorite (nZVI-R) composite was successfully synthesized through incorporation of nano-zero valent iron (nZVI) into the natural rectorite as supports. Iron ions were imbedded in the interlayer of rectorite clay via an ion-exchange reaction, and then the exchangeable Fe(III) cations were reduced to nZVI by NaBH4 in solution. The confinement of Fe crystal growth in the interlayer regions of rectorite resulted in the formation of nZVI particles at ca. 10.3 nm. The structure, morphology, Fe species, crystal phase, and elemental composition of the prepared nZVI-R composite materials were characterized using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence (XRF). Comparing with the commercially available nZVI-Junye, nZVI prepared in laboratory (nZVI-Lab) and Na-rectorite, the synthesized nZVI-R composite in this study showed superior decolorization efficiency for Orange II with 0.2 g of nZVI-R and a complete removal of Orange II achieved in less than 10 min. On the basis of FT-IR spectra, the mechanism for nZVI-R in the discoloration of Orange II was also postulated. This nZVI-R composite has potential applications in cleaning up environmental contaminants such as organic dyes or halogen compounds. (C) 2012 Published by Elsevier B.V.