The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier tr...The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy （FTIR）, and H20 adsorption mechanism on the surface of lignite pyrolysis was inferred. Two major changes in the pore structure of lignite char were observed as temperature increased in 105-200 ℃ and 500-700 ℃. Pyrolysis temperature is a significant factor in removing carboxyl and phenolic hydroxyl from lignite. Variation of ether bond content can be divided into three stages; the content initially increased, then decreased, and finally increased. The equilibrium adsorption ratio, content of oxygen-containing groups, and variation of pore volume below 700° were closely correlated with each other. The amount of adsorbed water on char pyrolyzed at 700 ℃ increased. Moreover, the adsorption capacity of the lignite decreased, and the adsorption state changed.展开更多
A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that ...A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that the pure crystalline product was obtained with the structure of LTA-type zeolite.SEM investigations showed that the well-defined LTA-Z crystals exhibited uniform size with the same cubic shape.The maximum AF adsorption amount was observed at pH=5,slightly lower than pHPZC of LTA-Z.Higher temperature favored AF adsorption onto LTA-Z and it was an endothermic process.Furthermore,AF adsorption amount increased with initial AF concentration increasing and LTA-Z dosage decreasing.Surface sorption governed this process at the initial 120 min period,followed by the internal diffusion of AF molecules between porous sites.The Langmuir model was determined as the adsorption isothermal,suggesting that the monolayer coverage of AF on LTA-Z surface was involved.展开更多
基金Supported by the National Science Foundation of China(Nos.21566029,21566028and 21266017)
文摘The effect of pyrolysis on the microstructure and moisture adsorption of lignite was investigated with low field nuclear magnetic resonance spectroscopy. Changes in oxygen-containing groups were analyzed by Fourier transform infrared spectroscopy （FTIR）, and H20 adsorption mechanism on the surface of lignite pyrolysis was inferred. Two major changes in the pore structure of lignite char were observed as temperature increased in 105-200 ℃ and 500-700 ℃. Pyrolysis temperature is a significant factor in removing carboxyl and phenolic hydroxyl from lignite. Variation of ether bond content can be divided into three stages; the content initially increased, then decreased, and finally increased. The equilibrium adsorption ratio, content of oxygen-containing groups, and variation of pore volume below 700° were closely correlated with each other. The amount of adsorbed water on char pyrolyzed at 700 ℃ increased. Moreover, the adsorption capacity of the lignite decreased, and the adsorption state changed.
基金supported by the National Natural Science Foundation of China (Grant No. 51002040)New Century Excellent Talents in Heilongjiang Provincial Universities (Grant No. 1253-NCET-010)+2 种基金Natural Science Youth Fund of Heilongjiang Province (Grant No. QC2012C084)Science Foundation of the Heilongjiang Education Office (Grant No. 12521071)Young Outstanding Talents Project of Harbin University of Science and Technology
文摘A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that the pure crystalline product was obtained with the structure of LTA-type zeolite.SEM investigations showed that the well-defined LTA-Z crystals exhibited uniform size with the same cubic shape.The maximum AF adsorption amount was observed at pH=5,slightly lower than pHPZC of LTA-Z.Higher temperature favored AF adsorption onto LTA-Z and it was an endothermic process.Furthermore,AF adsorption amount increased with initial AF concentration increasing and LTA-Z dosage decreasing.Surface sorption governed this process at the initial 120 min period,followed by the internal diffusion of AF molecules between porous sites.The Langmuir model was determined as the adsorption isothermal,suggesting that the monolayer coverage of AF on LTA-Z surface was involved.
