The adsorption of 2,4-dinitrophenol and 2.6-dinitrophenol on non-polar and polar adsorbents was studied. The results showed that the equilibrium adsorption did not comply with the Langmuir equation and was not mono-la...The adsorption of 2,4-dinitrophenol and 2.6-dinitrophenol on non-polar and polar adsorbents was studied. The results showed that the equilibrium adsorption did not comply with the Langmuir equation and was not mono-layer absorption. It is of interest to notice that the effect of pH on the adsorption of 2.4-or 2,6-dinitrophenol onto ADS-7 and ADS-21 was very small. The result is explained by hydrogen bonding interaction between 2, 4- or 2. 6-dinitrophenol and the adsorbent ADS21. The large adsorption capacity of dinitrophenol onto ADS-21, which was about 500 mg/g at an equilibrium concentration of 400 mg/L. and the small dinitrophenol leakage in the effluent from ADS- 21 column presented a good prospect for treatment of wastewater containing dinitrophenol with absorbent ADS-21.展开更多
A strongly hydrophilic hydrogen-bonding adsorbent-macroporous crosslinked poly(N- vinyl-acetamide). which contain both hydrogen bond acceptor and donator, was synthesized. Adsorption mechanism and dynamic adsorption o...A strongly hydrophilic hydrogen-bonding adsorbent-macroporous crosslinked poly(N- vinyl-acetamide). which contain both hydrogen bond acceptor and donator, was synthesized. Adsorption mechanism and dynamic adsorption of tannin from aqueous solution onto the adsorbent were investigated. Most of the differential adsorption heats for various adsorption capacities calculated from the adsorption isotherms according to Clapeyron-Clausius equation lay in the range of hydrogen bond energy (8-50kJ/mol). Adsorption properties of the adsorbent were studied in detail. These results revealed a hydrogen bonding mechanism of the adsorption of tannin from aqueous solution onto the adsorbent. The result of the dynamic adsorption of tanning with the initial concentration under 600 mg/L showed that the adsorption rate of tannin exceeded 90% when the flow rate was 3BV/h and the effluent volume reached 100 BV. Therefore, the developed hydrogen-bonding adsorbent--macroporous crosslinked poly(N-vinyl-acetamide)—is an excellent adsorbent to remove tannin from extract of natural products. and has great value in application.展开更多
The adsorption dynamics for phenol in aqueous solution of the adsorbent based on polystyrene was studied. In order to distinguish with the Boyd quasi-homogeneous model of the inner structure of ion-exchanger, the part...The adsorption dynamics for phenol in aqueous solution of the adsorbent based on polystyrene was studied. In order to distinguish with the Boyd quasi-homogeneous model of the inner structure of ion-exchanger, the particle diffusion model including surface diffusion model and pore diffusion model was suggested which is suitable to the macroporous adsorbent. The diffusiondetermination step of the adsorption process was established and the effective diffusion coefficient was also determined. The influence of surface diffusion and pore diffusion on the particle diffusion rate was investigated qualitatively. All of these were very important to improve the structure of the macroporous adsorbent in order to improve the mass-transfer rate.展开更多
Two hydrogen-bonding adsorbents-macroporous crosslinked poly(p-nitrostyrene) and poly(p-vinylbenzyl amide)--were synthesized, and the absorption property of phenol from cyclohexane solution onto the adsorbents was stu...Two hydrogen-bonding adsorbents-macroporous crosslinked poly(p-nitrostyrene) and poly(p-vinylbenzyl amide)--were synthesized, and the absorption property of phenol from cyclohexane solution onto the adsorbents was studied. The differential adsorption heats for varied adsorption capacities calculated from the adsorption isotherms according to the Clapeyron-Clausius equation lay in the range of hydrogen bond energy (8-50kJ/mol). The adsorption capacity of o-nitrophenol in cyclohexane was much less than that of phenol under the same condition. The adsorption capacity of phenol from cyclohexane onto polyacrylonitile was much less than that onto poly(p-nitrostyrene) or poly(p-vinylbenzyl amide). All these results revealed that adsorption of phenol from cyclohexane by poly(p-nitrostyrene) or poly(p-vinylbenzyl amide) is based on hydrogen-bonding.展开更多
The film diffusion mass-transfer process of adsorption of phenol on macroporous polystyrene resin was investigated in detail In order to revise the Boyd film diffusion kinetics equation, the out-surface structure of t...The film diffusion mass-transfer process of adsorption of phenol on macroporous polystyrene resin was investigated in detail In order to revise the Boyd film diffusion kinetics equation, the out-surface structure of the macroporous resin and that of gel-type ion-exchange resin was compared and the new film diffusion equation was also suggested. These results showed that the film diffusion was influenced by porosity of the macroporous resin greatly, which differed from the film diffusion behavior of ion-exchange resin obviously.展开更多
Spherical macroporous copolymers of methyl acrylate and trimethylolpropane triacrylate with different surface and pore structure were synthesized via suspension polymerization. and their surface and pore structure wer...Spherical macroporous copolymers of methyl acrylate and trimethylolpropane triacrylate with different surface and pore structure were synthesized via suspension polymerization. and their surface and pore structure were characterized by measurements of surface area, apparent density and skeleton density and calculation of average pore diameter The results revealed that crosslinking degree and porogent determined the physical structure of these copolymers. Some of the copolymers were applied to adsorptive purification of ginkgo leaves extract to enhance the content of flavonoids, the results showed that most of the copolymers could be used to increase the flavonoids content.展开更多
The adsorption isotherms of caffeine from aqueous solution onto three hydrogen donating adsorbents - hydroxypolystyrene. polystyrene-azo-pyrogallol, and D72 resin-were measured. The adsorption enthalpies calculated fr...The adsorption isotherms of caffeine from aqueous solution onto three hydrogen donating adsorbents - hydroxypolystyrene. polystyrene-azo-pyrogallol, and D72 resin-were measured. The adsorption enthalpies calculated from the isotherms according to the Clausius-Clapeyron equation were-24~ -36kJ/mol, -32~ -37kJ/mol. and -19~ -24kJ/mol respectively These values implied that the absorption processes were based on hydrogen bonding. Furthermore, the mechanism of the adsorption of caffeine onto D72 resin was studied by IR spectra and the small molecular model experiments. and the results showed that the adsorption of caffeine onto hydrogen donating adsorbents was based on hydrogen bonding.展开更多
Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization. The properties of the obt...Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization. The properties of the obtained adsorbent were also investigated in detail. The results showed that the water permeability could be improved by adding hydroxyl-containing organic compound moiety into the adsorbent. The specific surface area and average pore diameter of these adsorbents increased while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.展开更多
Spherical crosslinked polystyrene-isocyanuric acid resin was synthesized by reaction of chloromethylated polystyrene with isocyanuric acid. The sorption isotherms of phenol from aqueous solution and cyclohexane soluti...Spherical crosslinked polystyrene-isocyanuric acid resin was synthesized by reaction of chloromethylated polystyrene with isocyanuric acid. The sorption isotherms of phenol from aqueous solution and cyclohexane solution onto the resin were measured. It is of interest to notice that the resin sorbed phenol efficiently though its specific surface area was 0 and did not swell in water, and the sorption capacity.from aqueous solution was close to that of phenol onto XAD-4 at the same equilibrium concentration. Sorption enthalpies calculated from the isotherms according to the Clausius-Clapeyron equation were -2I~ -25lJ/mol and -39~ -41kJ/mol respectively. These values implied that the sorption processes were based on hydrogen bonding. In addition the details of the hydrogen bonding between the active sites of the resin and phenol were suggested.展开更多
Absorption of phenol, catechol and resorcinol. which vary in their ability to interact with the adsorbent through hydrogen bond, were used to investigate the adsorption mechanistic interaction. The adsorption enthalpi...Absorption of phenol, catechol and resorcinol. which vary in their ability to interact with the adsorbent through hydrogen bond, were used to investigate the adsorption mechanistic interaction. The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out. The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity On the other hand the more of the groups available for hydrogen bond interaction. the higher of the adsorption affinity These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.展开更多
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164)
文摘The adsorption of 2,4-dinitrophenol and 2.6-dinitrophenol on non-polar and polar adsorbents was studied. The results showed that the equilibrium adsorption did not comply with the Langmuir equation and was not mono-layer absorption. It is of interest to notice that the effect of pH on the adsorption of 2.4-or 2,6-dinitrophenol onto ADS-7 and ADS-21 was very small. The result is explained by hydrogen bonding interaction between 2, 4- or 2. 6-dinitrophenol and the adsorbent ADS21. The large adsorption capacity of dinitrophenol onto ADS-21, which was about 500 mg/g at an equilibrium concentration of 400 mg/L. and the small dinitrophenol leakage in the effluent from ADS- 21 column presented a good prospect for treatment of wastewater containing dinitrophenol with absorbent ADS-21.
基金Supported by the National Natural Science Foundation of China! (Grant No. 29574164)
文摘A strongly hydrophilic hydrogen-bonding adsorbent-macroporous crosslinked poly(N- vinyl-acetamide). which contain both hydrogen bond acceptor and donator, was synthesized. Adsorption mechanism and dynamic adsorption of tannin from aqueous solution onto the adsorbent were investigated. Most of the differential adsorption heats for various adsorption capacities calculated from the adsorption isotherms according to Clapeyron-Clausius equation lay in the range of hydrogen bond energy (8-50kJ/mol). Adsorption properties of the adsorbent were studied in detail. These results revealed a hydrogen bonding mechanism of the adsorption of tannin from aqueous solution onto the adsorbent. The result of the dynamic adsorption of tanning with the initial concentration under 600 mg/L showed that the adsorption rate of tannin exceeded 90% when the flow rate was 3BV/h and the effluent volume reached 100 BV. Therefore, the developed hydrogen-bonding adsorbent--macroporous crosslinked poly(N-vinyl-acetamide)—is an excellent adsorbent to remove tannin from extract of natural products. and has great value in application.
文摘The adsorption dynamics for phenol in aqueous solution of the adsorbent based on polystyrene was studied. In order to distinguish with the Boyd quasi-homogeneous model of the inner structure of ion-exchanger, the particle diffusion model including surface diffusion model and pore diffusion model was suggested which is suitable to the macroporous adsorbent. The diffusiondetermination step of the adsorption process was established and the effective diffusion coefficient was also determined. The influence of surface diffusion and pore diffusion on the particle diffusion rate was investigated qualitatively. All of these were very important to improve the structure of the macroporous adsorbent in order to improve the mass-transfer rate.
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164 and 29974015)
文摘Two hydrogen-bonding adsorbents-macroporous crosslinked poly(p-nitrostyrene) and poly(p-vinylbenzyl amide)--were synthesized, and the absorption property of phenol from cyclohexane solution onto the adsorbents was studied. The differential adsorption heats for varied adsorption capacities calculated from the adsorption isotherms according to the Clapeyron-Clausius equation lay in the range of hydrogen bond energy (8-50kJ/mol). The adsorption capacity of o-nitrophenol in cyclohexane was much less than that of phenol under the same condition. The adsorption capacity of phenol from cyclohexane onto polyacrylonitile was much less than that onto poly(p-nitrostyrene) or poly(p-vinylbenzyl amide). All these results revealed that adsorption of phenol from cyclohexane by poly(p-nitrostyrene) or poly(p-vinylbenzyl amide) is based on hydrogen-bonding.
文摘The film diffusion mass-transfer process of adsorption of phenol on macroporous polystyrene resin was investigated in detail In order to revise the Boyd film diffusion kinetics equation, the out-surface structure of the macroporous resin and that of gel-type ion-exchange resin was compared and the new film diffusion equation was also suggested. These results showed that the film diffusion was influenced by porosity of the macroporous resin greatly, which differed from the film diffusion behavior of ion-exchange resin obviously.
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164)
文摘Spherical macroporous copolymers of methyl acrylate and trimethylolpropane triacrylate with different surface and pore structure were synthesized via suspension polymerization. and their surface and pore structure were characterized by measurements of surface area, apparent density and skeleton density and calculation of average pore diameter The results revealed that crosslinking degree and porogent determined the physical structure of these copolymers. Some of the copolymers were applied to adsorptive purification of ginkgo leaves extract to enhance the content of flavonoids, the results showed that most of the copolymers could be used to increase the flavonoids content.
基金Supported by the National Natural Science Fsundation of China !(Grant No. 29574164)
文摘The adsorption isotherms of caffeine from aqueous solution onto three hydrogen donating adsorbents - hydroxypolystyrene. polystyrene-azo-pyrogallol, and D72 resin-were measured. The adsorption enthalpies calculated from the isotherms according to the Clausius-Clapeyron equation were-24~ -36kJ/mol, -32~ -37kJ/mol. and -19~ -24kJ/mol respectively These values implied that the absorption processes were based on hydrogen bonding. Furthermore, the mechanism of the adsorption of caffeine onto D72 resin was studied by IR spectra and the small molecular model experiments. and the results showed that the adsorption of caffeine onto hydrogen donating adsorbents was based on hydrogen bonding.
基金uported by the National Natural Science Foundation of China !(Grant No. 29574164)
文摘Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization. The properties of the obtained adsorbent were also investigated in detail. The results showed that the water permeability could be improved by adding hydroxyl-containing organic compound moiety into the adsorbent. The specific surface area and average pore diameter of these adsorbents increased while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164 and 29974015)
文摘Spherical crosslinked polystyrene-isocyanuric acid resin was synthesized by reaction of chloromethylated polystyrene with isocyanuric acid. The sorption isotherms of phenol from aqueous solution and cyclohexane solution onto the resin were measured. It is of interest to notice that the resin sorbed phenol efficiently though its specific surface area was 0 and did not swell in water, and the sorption capacity.from aqueous solution was close to that of phenol onto XAD-4 at the same equilibrium concentration. Sorption enthalpies calculated from the isotherms according to the Clausius-Clapeyron equation were -2I~ -25lJ/mol and -39~ -41kJ/mol respectively. These values implied that the sorption processes were based on hydrogen bonding. In addition the details of the hydrogen bonding between the active sites of the resin and phenol were suggested.
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164 and 29974015)
文摘Absorption of phenol, catechol and resorcinol. which vary in their ability to interact with the adsorbent through hydrogen bond, were used to investigate the adsorption mechanistic interaction. The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out. The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity On the other hand the more of the groups available for hydrogen bond interaction. the higher of the adsorption affinity These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.
