Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation w...Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation well (r 2 ≥0.91) and the adsorption extents increased in the order: metolachlor < acetochlor < pratilachlor < butachlor. The product of Freundlich adsorption constants, Kf (1/n), showed to have a good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that OM is the primary factor dominating in the adsorption process of these asetanilide herbicides. Multivariant correlation regression between Kf (1/n) and two factors, water solubility (S.) of herbicides and OM, was also performed. Kf(1/n) correlated with 1/S. and OM/S. well, showing that high S. corresponds to a weak tendency to adsorb on soils. Infrared (IR) spectra and electron spin resonance (ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the main adsorption mechanisms of these acetanilide herbicides. The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.展开更多
Adsorption and desorption behavior of Yb （III） by SQD-85 resin was investigated by various chemical methods and IR spectrometry. The adsorption capacity of SQD-85 resin for Yb （III） was studied as a function of so...Adsorption and desorption behavior of Yb （III） by SQD-85 resin was investigated by various chemical methods and IR spectrometry. The adsorption capacity of SQD-85 resin for Yb （III） was studied as a function of solution pH, initial concentration of Yb（III）, temperature and contact time. The optimal pH for the adsorption was 5.50 in the HAc-NaAc system, and the maximum adsorption capacity was estimated to be 347.6 mg/g at 308 K. The isotherms adsorption data fit well with Langmuir model. The adsorption kinetics data are in agreement with pseudo-second-order model. Thermodynamic parameters indicate that Yb （III） adsorption by SQD-85 resin is endothermic and spontaneous in nature. Thomas model is reasonably accurate in predicting experimental column results. The dynamic desorption rate of Yb（III） can increase to 97.3% when the elution agent is 1.0 mol/L HCl. These results suggest that Yb（III） in aqueous solution can be removed and recovered by SQD-85 resin efficiently.展开更多
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
基金the National Natural Science Foundation of China (Nos: 29477274 and 3967O420)
文摘Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundich equation well (r 2 ≥0.91) and the adsorption extents increased in the order: metolachlor < acetochlor < pratilachlor < butachlor. The product of Freundlich adsorption constants, Kf (1/n), showed to have a good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that OM is the primary factor dominating in the adsorption process of these asetanilide herbicides. Multivariant correlation regression between Kf (1/n) and two factors, water solubility (S.) of herbicides and OM, was also performed. Kf(1/n) correlated with 1/S. and OM/S. well, showing that high S. corresponds to a weak tendency to adsorb on soils. Infrared (IR) spectra and electron spin resonance (ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the main adsorption mechanisms of these acetanilide herbicides. The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.
基金Project (2011007) supported by Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, Zhejiang Sci-tech University, ChinaProject (2010C32085) supported by Science and Technology Department of Zhejiang Province, China
文摘Adsorption and desorption behavior of Yb （III） by SQD-85 resin was investigated by various chemical methods and IR spectrometry. The adsorption capacity of SQD-85 resin for Yb （III） was studied as a function of solution pH, initial concentration of Yb（III）, temperature and contact time. The optimal pH for the adsorption was 5.50 in the HAc-NaAc system, and the maximum adsorption capacity was estimated to be 347.6 mg/g at 308 K. The isotherms adsorption data fit well with Langmuir model. The adsorption kinetics data are in agreement with pseudo-second-order model. Thermodynamic parameters indicate that Yb （III） adsorption by SQD-85 resin is endothermic and spontaneous in nature. Thomas model is reasonably accurate in predicting experimental column results. The dynamic desorption rate of Yb（III） can increase to 97.3% when the elution agent is 1.0 mol/L HCl. These results suggest that Yb（III） in aqueous solution can be removed and recovered by SQD-85 resin efficiently.
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.
