Бидний тухай
Багш ажилтан
The tendency of use of coals under the restrictions of environmental safety demands a more detailed understanding of its structure for its various processing. Particularly, processing of brown coals is the most important for us (Mongolia) in the near future, since the brown coal is the most abundant (several hundred million tonnes) and approachable (more than 200 coal occurrences) resource in the country. Selected coal owns low degree of carbon containment. Additionally, oxygen and several trace elements content can be determined by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS). The analysis indicates dominations of elements such as silicon, calcium, aluminium and iron in the raw coal. By using the SEM results the Fourier transform infrared (FTIR) bands particularly, long wave region, are identified. Two extraction products are prepared in the refluxing processing of raw coal in solvents such as pyridine and ionic liquid (1-butyl-3-methilimidazolium chloride). Moreover, separated from the extractions, the insoluble coal residues washed with methanol, were analyzed as well. Structural features are determined in the brown coal extraction products after the processing with the solvents such as pyridine and ionic liquid (1-butyl-3-methilimidazolium chloride). Coal extraction characterizations thereafter, are compared to its raw coal functional groups using by FTIR spectroscopy. The difference in spectra is observed even for the used solvents. For example, an extraction FTIR spectrum in the pyridine treatment presents changes mostly in the long wave of the vibrational region. Short wave bands at 3400 and 3000-2800 cm-1 are the least affected under the pyridine processing. In contrast, long wave bands were vanished or weakened by intensity, essentially, the mineral bands in 600-400 cm-1 region of wave number. An intensity of whole infrared spectrum is low powered in the pyridine used solvent case, but an opposite way for the ionic liquid treatment. In the ionic liquid processing the spectrum is involved wholly, means the short and long wave regions of vibration. Ionic liquid and coal interaction calls stretching bond around 3000-2800 cm-1 to be affected and a blue shift of C-O bands at 1600 cm-1 and of minerals at 600-400 cm-1. It should be noted that the ionic liquid is still a powerful solvent in the meaning of solving insoluble material like coal. Insoluble coal residues are either analyzed by FTIR spectroscopy and compared to the raw coal infrared spectrum. In both pyridine and ionic liquid cases the residues were well washable from the solvent by methanol. FTIR spectra proves that in both case infrared spectra were renewable by means the original functional groups are similar as its raw coal.
Abstract: In the present work, the extraction of Mongolian Baganuur coal in solvents as pyridine and ionic liquid with 1-butyl-3-methyl-imidazolium chloride ([Bmim]Cl) anion was first applied. The as recieved coal, its extracts and insoluble residues were then characterized using the Fourier transform infrared (FTIR) spectroscopy. The obtained FTIR spectra have revealed many new features in the field of coal study. An appearance or sharpening of the particular bands after the chemical treatment allow a determination of inactive or weak fundamental vibrations precisely. Some emphasis are as follows, substantial quantitative change, the integrated area decrease of water molecule band at 3260 cm−1 comparing to as received sample and ionic liquid treated extract, can be seen for the extract spectrum in the pyridine treatment. Pyridine react to coal structure particularly in long-wave frequency zone means very susceptible to the oxygen containing functional group. Upon interaction between acidic group of the coal and the basic solvent as pyridine, the inter-fragment hydrogen and ester bonding in the coal structure is breaking, thus increasing the solubility of the individual fragments via producing new components. Towards forming H bond in the short wave zone Cl− anion shows a strong effect on the coal molec-ular structure. A stabilization of hydrogen bonds show well fluidization and a strong intermolecular interaction of the process via its powerful spectral intensity that is followed many new bands and con-siderable strengthening of band spectral integral area in this frequency region. In long-wave vibrational region there are appearances of many new bands, shift in frequency and depletion of the as recieved coal bands. [Bmim]Cl treatment exhibits the highest effect of the disruption on the carboxylic acids dimer.