Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)...Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)and Fourier Transform Infrared Spectroscopy(FTIR)techniques.X-ray parameters of coal like interlayer spacing(d_(002)),crystallite size(L_(c)),aroamticity(f_(a)),average number of aromatic layers(N_(c)),and coal rank(I_(26)/I_(20))have been determined using profilefitting software.Considerable variation is observed in treated coals in comparison to the demineralized coals.The d_(002)values of treated coals have increased in both the media showing increase in disordering of organic moieties.A linear relationship has been observed between d_(002)values with the volatile matter of the coals.Similarly,the d_(002)values show linear relationship with C_(dmf) contents for demineralized as well as for the treated coals in both the media.The L_(c) and N_(c) values have decreased in treated coals corresponding to demineralized coals.The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity(f_(a))increases with increase in rank and shows a linear relationship with the vitrinite reflectance.The corresponding I_(26)/I_(20)values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium.FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals(SMCs)in both the media,the corresponding bands at 1550-1490 and 1355-1315 cm^(-1) respectively.FTIR study confirms that nitration is the predominant phenomenon,though,oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs.In comparison to raw coals,the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.展开更多
基金We thank the Director,CSIR-Central Institute of Mining and Fuel Research,Dhanbad for permission to publish this paper.We also thank our colleagues at the Resource Quality Assessment and CTL Research Group for their support.
文摘Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)and Fourier Transform Infrared Spectroscopy(FTIR)techniques.X-ray parameters of coal like interlayer spacing(d_(002)),crystallite size(L_(c)),aroamticity(f_(a)),average number of aromatic layers(N_(c)),and coal rank(I_(26)/I_(20))have been determined using profilefitting software.Considerable variation is observed in treated coals in comparison to the demineralized coals.The d_(002)values of treated coals have increased in both the media showing increase in disordering of organic moieties.A linear relationship has been observed between d_(002)values with the volatile matter of the coals.Similarly,the d_(002)values show linear relationship with C_(dmf) contents for demineralized as well as for the treated coals in both the media.The L_(c) and N_(c) values have decreased in treated coals corresponding to demineralized coals.The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity(f_(a))increases with increase in rank and shows a linear relationship with the vitrinite reflectance.The corresponding I_(26)/I_(20)values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium.FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals(SMCs)in both the media,the corresponding bands at 1550-1490 and 1355-1315 cm^(-1) respectively.FTIR study confirms that nitration is the predominant phenomenon,though,oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs.In comparison to raw coals,the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.
