The adsorption of dibenzofuran （DBF） on three commercial granular activated carbons （GAC） was investigated to correlate the adsorption equilibrium and kinetics with the morphological characteristics of activated c...The adsorption of dibenzofuran （DBF） on three commercial granular activated carbons （GAC） was investigated to correlate the adsorption equilibrium and kinetics with the morphological characteristics of activated carbons. Breakthrough experiment was conducted to determine the isotherm and kinetics of dibenzofuran on the activated carbons. All-the experiment runs were performed in a fixed bed with a process temperature of 368 K. The effects of adsorbent morphological properties on the kinetics of the adsorption process were studied. The equilibrium data are found satisfactory fitted to the Langmuir isotherm. An intraparticle diffusion model based on the obtained Langmuir isotherm was＇developed for predicting the fixed bed adsorption of dibenzofuran. The result indicated that this model fit all the breakthrough curves well. The surface diffusion coefficients of dibenzofuran on the activated carbon are calculated, and a relationship with the microporosity is found. As it was expected, the dibenzofuran molecule finds more kinetic restrictions for the diffusion in those carbons with narrower pore diameter.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
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
Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673－773 K, 25－35 MPa) are investigated by molecular dynamics simulation with site-site models. It...Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673－773 K, 25－35 MPa) are investigated by molecular dynamics simulation with site-site models. It is found that at the ambient condition, the water molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond interaction between supercritical water molecules decreases dramatically under supercritical conditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical conditions increase by 30－180 times than those at the ambient condition. With the temperature approaching the critical temperature, the change of diffusion coefficient with pressure becomes pronounced.展开更多
The adsorption of dibenzofuran on three commercial granular activated carbons (ACs) was investigated by dynamic experiment to correlate the adsorption equilibrium and kinetics with the structure of activated carbons.P...The adsorption of dibenzofuran on three commercial granular activated carbons (ACs) was investigated by dynamic experiment to correlate the adsorption equilibrium and kinetics with the structure of activated carbons.Physical properties including surface area, average pore diameter, micropore area and micropore volume of the activated carbons were characterized by N2 adsorption experiment on ASAP2010. To calculate the adsorption parameters, adsorption isotherm data were fitted to the Langmuir equation, and adsorption kinetic data were fitted to the linear driving force (LDF) diffusion model. From the correlation results, it is concluded that the adsorption equilibrium and diffusion coefficient of dibenzofuran on activated carbon are controlled respectively by the total adsorbent surface area and the adsorbent pore diameter.展开更多
Self-diffusion coefficients of exponential-six fluids are studied using equilibrium molecular dynamics simulation technique. Mean-square displacements and velocity autocorrelation functions are used to calculate self-...Self-diffusion coefficients of exponential-six fluids are studied using equilibrium molecular dynamics simulation technique. Mean-square displacements and velocity autocorrelation functions are used to calculate self-diffusion coefficients through Einstein equation and Green-Kubo formula. It has been found that simulation results are in good agreement with experimental data for liquid argon which is taken as exponential-six fluid. The effects of density, temperature and steepness factor for repulsive part of exponential-six potential on self-diffusion coefficients are also investigated. The simulation results indicate that the self-diffusion coefficient of exponential-six fluid increases as temperature increases and density decreases. In addition, the larger self-diffusion coefficients are obtained as the steepness factor increases at the same temperature and density condition.展开更多
基金Supported by the National Natural Science Foundation of China （29936100） and the Natural Science Foundation of Guangdong Province （7010327）. The authors would like to thank to Pro. GU0 Haifu in Chemistry and Chemical Engineering department of Zhaoqing University for providing the necessary facilities to conduct part of the experimental work reported in this study.
文摘The adsorption of dibenzofuran （DBF） on three commercial granular activated carbons （GAC） was investigated to correlate the adsorption equilibrium and kinetics with the morphological characteristics of activated carbons. Breakthrough experiment was conducted to determine the isotherm and kinetics of dibenzofuran on the activated carbons. All-the experiment runs were performed in a fixed bed with a process temperature of 368 K. The effects of adsorbent morphological properties on the kinetics of the adsorption process were studied. The equilibrium data are found satisfactory fitted to the Langmuir isotherm. An intraparticle diffusion model based on the obtained Langmuir isotherm was＇developed for predicting the fixed bed adsorption of dibenzofuran. The result indicated that this model fit all the breakthrough curves well. The surface diffusion coefficients of dibenzofuran on the activated carbon are calculated, and a relationship with the microporosity is found. As it was expected, the dibenzofuran molecule finds more kinetic restrictions for the diffusion in those carbons with narrower pore diameter.
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.
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 State Key Fundamental Research Plan (NO. G2000048) and the National High Performance Computing Foundation of China (No. 99118).
文摘Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673－773 K, 25－35 MPa) are investigated by molecular dynamics simulation with site-site models. It is found that at the ambient condition, the water molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond interaction between supercritical water molecules decreases dramatically under supercritical conditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical conditions increase by 30－180 times than those at the ambient condition. With the temperature approaching the critical temperature, the change of diffusion coefficient with pressure becomes pronounced.
文摘The adsorption of dibenzofuran on three commercial granular activated carbons (ACs) was investigated by dynamic experiment to correlate the adsorption equilibrium and kinetics with the structure of activated carbons.Physical properties including surface area, average pore diameter, micropore area and micropore volume of the activated carbons were characterized by N2 adsorption experiment on ASAP2010. To calculate the adsorption parameters, adsorption isotherm data were fitted to the Langmuir equation, and adsorption kinetic data were fitted to the linear driving force (LDF) diffusion model. From the correlation results, it is concluded that the adsorption equilibrium and diffusion coefficient of dibenzofuran on activated carbon are controlled respectively by the total adsorbent surface area and the adsorbent pore diameter.
基金Supported by the National Natural Science Foundation of China(No.29736170).
文摘Self-diffusion coefficients of exponential-six fluids are studied using equilibrium molecular dynamics simulation technique. Mean-square displacements and velocity autocorrelation functions are used to calculate self-diffusion coefficients through Einstein equation and Green-Kubo formula. It has been found that simulation results are in good agreement with experimental data for liquid argon which is taken as exponential-six fluid. The effects of density, temperature and steepness factor for repulsive part of exponential-six potential on self-diffusion coefficients are also investigated. The simulation results indicate that the self-diffusion coefficient of exponential-six fluid increases as temperature increases and density decreases. In addition, the larger self-diffusion coefficients are obtained as the steepness factor increases at the same temperature and density condition.
