Mineralogy and Morphological Characterization of Technogenic Magnetic Particles (TMP) from Industrial Dust: Insights into Environmental Implications

Abstract

AbstractMagnetic measurements are notable among the recent developments to encounter the spatial distribution and grades of heavy metal pollution and to determine the anthropogenic sources of such pollution. The present investigation aims towards characterizing the magnetic properties, microstructures, and mineral phase of the Technogenic Magnetic Particles (TMP) in the urban soils and to enlighten their potential environmental implications. The TMP considered for the present study are collected from Farakka area (in and around Farakka Super Thermal Power Station, FSTPS), W.B., India. The magnetic susceptibility, morphology and microstructures of the TMPs are studied using Bartington MS-2 Susceptibility Meter, Scanning Electron Microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The weight percentage of TMP in the concerned topsoil ranges from 0.05% to 0.5% (on an average). The magnetic susceptibility of the samples ranges within 263.4 × 10−8 m3/kg to 3.9 × 10−8 m3/kg. The collected samples displayed huge diversity of susceptibility values which was inevitably identified as a function of concentration and mineral composition. According to the XRD analysis, it is evident that the technogenic iron mainly occurs within the structures of silicates and other oxides. The TMP in general includes three dominant morphological forms: spherical, irregular shaped and aggregate particles. The spherical TMP belongs to a size range of 10–200 μm with a modal value of about 50 μm. EDAX studies indicating that the TMP are enriched in iron, magnesium etc. which are interpreted to have been incorporated within the lattice of major minerals present on account of their large lattice size. The concentration of the TMP bears a positive correlation with that of the heavy metal concentration within urban soils. Thus, in a nutshell magnetic properties, microstructures and mineral phases of Titano-magnetite can serve as the identification of pollution sources in the urban soils.KeywordsTechnogenic Magnetic Particles (TMP)Urban soilsHeavy metalsSEM-EDSX-ray diffraction