Investigation of suspended particulate formation potential of some Nigerian coals

Abstract

Coal is often considered as a reliable and affordable energy source; however, its utilization poses environmental challenges due to particulate matter emissions. These emissions have severe consequences, making coal-related air pollution a critical concern. In spite of the renewed interest in coal utilization in Nigeria-driven by incessant petroleum shortages-limited studies have deeply examined the role of mineral matter and their contributions to the development of suspended particulates. This study aims to investigate the relationship between suspended particulate formation and the mineral properties of coal by examining the chemical structures, morphologies, and elemental compositions of coal samples from Odagbo (ODG), Lafia-Obi (LFO) and Onyeama (OYM) deposits in Nigeria to evaluate their potential for particulate generation. Three non-destructive analytical techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Fluorescence (XRF), were employed for characterization. FTIR results showed dominant Si–O and O–H functional groups, indicating the presence of kaolinite, quartz, and feldspar minerals. SEM micrographs showed distinct morphological differences, with LFO coal exhibiting loosely bound, angular mineral grains that are more susceptible to fragmentation. XRF analysis confirmed higher concentrations of silicon (Si), aluminium (Al), and iron (Fe) in LFO coal compared to the other samples. While FTIR suggested strong mineral signatures in OYM coal, combined SEM and XRF results indicate that LFO coal has the highest potential for suspended particulate formation. The results were compared with coals from other regions and showed that the studied samples performed better in some parameters, while others outperformed them in different aspects. Overall, the particulate formation potential follows the order: LFO>OYM>ODG. • Nigerian coals (Odagbo, Lafia-Obi, and Onyeama) were characterized using FTIR, SEM, and XRF. • FTIR spectra revealed dominant Si–O and O–H functional groups linked to quartz, kaolinite, and feldspar. • SEM micrographs showed porous, layered structures with mineral and metallic inclusions. • XRF analysis identified Si, Al, Fe, Sn, and Sb as major elements influencing particulate formation. • Findings indicate high potential for suspended particulate emissions from Nigerian coals