Extraction and chemical characterization of humic acid produced from lignite coals of arid region of Gujarat, Western India

Abstract In the current study, extraction of humic acid (HAs) from lignite fines of kutch basin of Gujarat (western India) were reported. The extraction was done by International Humic Substances Society (IHSS) method. Several analytical and spectroscopic techniques were used to characterize of extracted HAs. The gravimetric analysis showed (28.5% and 26.4%) of humic acid extraction from panandhro mines (PM) and mata-No-Madh mines (MNMM) respectively. UV–Vis spectroscopy revealed a high degree of humification, higher stability and aromatic nature. FTIR peaks demonstrated the presence of carboxylic, alcoholic, and phenolic functional groups. SEM/EDX analysis revealed that surface were smooth, non-porous and like loose sponge that showed the presence of major elements like C, O, F, Al, Na, S, Si, Ca, Ti and Fe. The combination of results gives a better and improved understanding of the nature of lignite coals of western India. It may be helpful in choosing suitable coals for the extraction of humic acid and using it for enhancing plant growth condition, soil enrichment and creating green energy solution. This study not only helps in the research related to extraction of humic acid from lignite but also creates a new avenue for the efficient and clean use of lignite.