The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed ...The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed according to the degree of affinity of organic groups to the trace elements. The results show that there is a possibility that trace elements, especially LREE, were bound to peripheral organic functional groups of middle rank coal macromolecule. The most possible functional group that binds trace element is the hydroxyl, and to the less degree, the asymmetric -CH3 and 〉CH2 stretching, -CH3 stretching, etc. The degree of affinity of trace elements to different functional groups varies. The tendency obeys the natural structural changing law of trace elements-- the periodic law. The deviation of some trace elements from this regular trend is attributed to the deviation of intrinsic ＂confusion degree＂ （conventional molar entropy） of the matter system of coal basin, which is affected by the inner and outer factors during the evolution.展开更多
The time evolution of coal structure during low temperature oxidation was investigated by oxidizing coal samples in air at 120 ℃ for periods of up to 14 days.The structure of the oxidized coal samples was characteriz...The time evolution of coal structure during low temperature oxidation was investigated by oxidizing coal samples in air at 120 ℃ for periods of up to 14 days.The structure of the oxidized coal samples was characterized by Fourier transform infrared spectroscopy(FTIR) and curve fitting analysis.The results show that carboxyl and ether groups are the main oxygen containing moieties in oxidized coal.Ethers are most abundant during the first 3 days of oxidation,thereafter carboxyl groups predominate.The content of carboxyl and ester functionality increases with oxidation time.The other oxygen containing groups vary in concentration over time.The amount of hydroxyl groups first decreases then increases and finally decrease again during the oxidation.The aliphatic structure and the degree of branching of the aliphatic chains is reduced as the oxidation proceeds.The proportion of aromatic structure increases with oxidation time.Obvious decomposition of aromatic rings occurs after about 9 days of oxidation.The aryl ester bands and the CH 3 /CH 2 ratio both have a good linear relationship to oxidation time.展开更多
基金supported by the National Science Foundation of China(Nos.41172143 and 40872101)Developmental Plan of Basic Research on Natural Science of Shanxi Province(20012JM5005)Science Research Plan of Shanxi education department(12JK0483)
文摘The relationship between trace elements in coal and organic functional groups of coal, also some of aromatic structure, was investigated by using curve fitting of infrared spectra. Cluster analysis was also performed according to the degree of affinity of organic groups to the trace elements. The results show that there is a possibility that trace elements, especially LREE, were bound to peripheral organic functional groups of middle rank coal macromolecule. The most possible functional group that binds trace element is the hydroxyl, and to the less degree, the asymmetric -CH3 and 〉CH2 stretching, -CH3 stretching, etc. The degree of affinity of trace elements to different functional groups varies. The tendency obeys the natural structural changing law of trace elements-- the periodic law. The deviation of some trace elements from this regular trend is attributed to the deviation of intrinsic ＂confusion degree＂ （conventional molar entropy） of the matter system of coal basin, which is affected by the inner and outer factors during the evolution.
基金supported by the Shaanxi Provincial Project of Special Foundation of Key Disciplinesthe Scientific Research Program Funded by Shaanxi Provincial Education Commission (No. 09JK583)the Seed Fund of Xi’an University of Science and Technology (No. 200745)
文摘The time evolution of coal structure during low temperature oxidation was investigated by oxidizing coal samples in air at 120 ℃ for periods of up to 14 days.The structure of the oxidized coal samples was characterized by Fourier transform infrared spectroscopy(FTIR) and curve fitting analysis.The results show that carboxyl and ether groups are the main oxygen containing moieties in oxidized coal.Ethers are most abundant during the first 3 days of oxidation,thereafter carboxyl groups predominate.The content of carboxyl and ester functionality increases with oxidation time.The other oxygen containing groups vary in concentration over time.The amount of hydroxyl groups first decreases then increases and finally decrease again during the oxidation.The aliphatic structure and the degree of branching of the aliphatic chains is reduced as the oxidation proceeds.The proportion of aromatic structure increases with oxidation time.Obvious decomposition of aromatic rings occurs after about 9 days of oxidation.The aryl ester bands and the CH 3 /CH 2 ratio both have a good linear relationship to oxidation time.
