Hematite nanopowder obtained from waste: Iron-removal sludge

Abstract

X-ray diffraction and Fourier-transform IR spectroscopy techniques were employed to confirm that heavy-tonnage iron-removal sludge wastes could be successfully used to synthesize hematite nanopowder (HM NP) with an average particle size of 42nm. The sizes of the HM NP particles were confirmed from the TEM images. The hematite particles mostly exhibit elongated irregular oval shapes and their sizes vary within 18–74nm, with a dominant fraction at 42–46nm. The obtained HM NPs were characterized by a saturation magnetization of ~1.5emu/g and a remanent magnetization of ~0.9emu/g. Low-temperature nitrogen adsorption measurements showed that the obtained powder had a large specific surface area (S=14m2/g) and well-developed mesoporosity (average pore size, 17.2nm). A comparison of the obtained results to data from other researchers suggests that this hematite powder has high potential for use in the preparation of sorbents for water purification.