Immobilization of nanoscale Fe 0 in and on PVA microspheres for nitrobenzene reduction

Abstract

In this study, nanoscale Fe 0 was immobilized in and on poly(vinyl alcohol) (PVA) microspheres by the inverse suspension crosslinked method. Two different sizes of Fe 0/PVA microspheres were synthesized in the presence and absence of dispersant. The chelating action between Fe 2+ and PVA was identified by Fourier transform infrared and X-ray photoelectron spectroscopy. The morphology and distribution of the obtained Fe 0/PVA microspheres were characterized by environmental scanning electron microscope, energy-dispersive X-ray spectrometry, and X-ray diffraction. Nanoscale Fe 0 particles were mostly dispersed over the surface of the microspheres. They were distributed more homogeneously on the surfaces of Fe 0/PVA microspheres with diameter of 600–700 μm than those with diameter of 10–12 μm. The nitrobenzene (NB) reduction reactions followed pseudo-first-order kinetics. The normalized surface rate constants ( k SA) values were determined to be 0.162 L h −1 m −2 for L-Fe 0/PVA microspheres, 0.098 L h −1 m −2 for S-Fe 0/PVA microspheres, and 0.023 L h −1 m −2 for nanoscale Fe 0 particles. Furthermore, with the analysis of the products by GC/MS, possible reductive pathways of NB by Fe 0/PVA microspheres were suggested. The recovery rates of iron in microspheres were determined to be 81.17% for large Fe 0/PVA and 60.31% for small Fe 0/PVA.