The effect of demineralization on Indian bituminous coal by filamentous fungus Aspergillus niger has been investigated. X-ray diffraction profile reveals the presence of inorganic components in the sample. Biosolubilised products were characterized by FT-IR, SEM-EDS and XRD. The study reveals that coal consist of a semi-crystalline turbostratic structure. The broad diffraction peak at 20~25.5o attributed to the crystalline carbon in the sample. Leaching process removed. Silicate, pyrite minerals and aluminates were removed considerably. The absence of morphological features corresponding to inorganic mineral grains confirms demineralization. The FTIR spectrum reveals the presence of aliphatic and aromatic stretching bands. During bio-solubilization the fungus produced acids like gluconic acid, oxalic acid and citric acid along with oxalates which are responsible for the demineralization in coal by the formation of mineral salts. EDS analysis reveals high percentage of carbon in bituminous coal than high volatile bituminous coal. The peak at 230-270 nm confirms the benzene-oxygen charge transfer in the sample.
Biodegradation, Coal characterization, Fungi, Aspergillus niger