In this paper, six kinds of activated carbons such as Ag+-activated carbon, Cu2+- activated carbon, Fe3+- activated carbon, activated carbon, Ba2+- activated carbon and Ca2+- activated carbon were prepared. The model ...In this paper, six kinds of activated carbons such as Ag+-activated carbon, Cu2+- activated carbon, Fe3+- activated carbon, activated carbon, Ba2+- activated carbon and Ca2+- activated carbon were prepared. The model for estimating activated energy of desorption was established. Temperature-programmed desorption (TPD) experiments were conducted to measure the TPD curves of n-hexanol and then estimate the activation energy for desorption of n-hexanol on the activated carbons. Results showed that the activation energy for the desorption of n-hexanol on the Ag+- activated carbon, the Cu2+- activated carbon and the Fe3+- activated carbon were higher than those of n-hexanol on the activated carbon, the Ca2+- activated carbon and the Ba2+- activated carbon.展开更多
Adsorption equilibrium experiments of phenol on the NKA II resin are separately conducted in the presence and absence of ultrasound at ambient temperature. The isotherm of phenol on the polymer adsorbent in the presen...Adsorption equilibrium experiments of phenol on the NKA II resin are separately conducted in the presence and absence of ultrasound at ambient temperature. The isotherm of phenol on the polymer adsorbent in the presence of ultrasonic field is firstly reported. Results indicated that the isotherm of phenol determined in the presence of ultrasound is lower than that in the absence of ultrasound. In addition, experiments also show that the use of ultrasound to the adsorption system of the phenol aqueous solution and NKA II resin could cause the rising of the temperature of the system in the order of 6 0C. The effect of ultrasound on the isotherm of the phenol on the NKA II resin mostly ascribes to the thermal effect and the non-thermal effect of ultrasonic field, and the role of the later is greater than that of the former.展开更多
In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatograp...In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatography （IGC） in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption （TPD） technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.展开更多
Desorption of volatile organic compounds (VOCs) from polymeric adsorbents by microwave was investigated experimentally. Two kinds of organic compounds, benzene and toluene, were separately used as adsorbates in this w...Desorption of volatile organic compounds (VOCs) from polymeric adsorbents by microwave was investigated experimentally. Two kinds of organic compounds, benzene and toluene, were separately used as adsorbates in this work. Results showed that the application of microwave to regenerate the polymeric adsorbents not only can get higher regeneration efficiency in comparison with the use of heat regeneration, but also make the temperatures of the fixed beds much lower than that when using the heat regeneration. The weaker the polarity of a polymeric adsorbent, the easier its regeneration was.展开更多
A new model, phase equilibrium-kinetics model (PEKM), for estimation of diffusion coefficient was proposed in this paper. Kinetic experiments of phenol desorption on NKAII resin in the presence and the absence of ultr...A new model, phase equilibrium-kinetics model (PEKM), for estimation of diffusion coefficient was proposed in this paper. Kinetic experiments of phenol desorption on NKAII resin in the presence and the absence of ultrasound were separately conducted, and diffusion coefficients of phenol within an adsorbent particle were estimated by means of proposed PEKM and classic simplified model. Results show that the use of ultrasound not only changes the phase equilibrium state of NKA II resin/phenol/water system which had been equilibrium at normal condition, but also enhances diffusion of phenol within the resin. The diffusion coefficient of phenol in the resin in the field of ultrasound increases in an order of magnitude in comparison with the diffusion coefficient determined under no ultrasound. Experimental results also indicated that the diffusion coefficients estimated by PEKM were more accurate than that estimated by the classic simplified model.展开更多
CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over the...CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuOγ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuOγ-Al2O3 catalyst prepared via plasma was much higher than that of the CuOγ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment.展开更多
Studied the effect of ionic strength on the uptake of taurine on a strong-basic anion exchange resin The batch phase equilibrium experiments of taurine on the anion exchange resin D290 were conducted at different ioni...Studied the effect of ionic strength on the uptake of taurine on a strong-basic anion exchange resin The batch phase equilibrium experiments of taurine on the anion exchange resin D290 were conducted at different ionic strength, and then the amounts of uptake of taurine on the resin at different pH were determined. The ion exchange mechanisms of taurine on the anion exchange resin at different pH were discussed. Experimental results showed that with increase of the ionic strength of solution, the adsorbed amount of taurine on the resin D290 decreased; Adding small amounts of NaOH or HCl into the system of taurine aqueous solution/D290 anion resin would nfake the amount of taurine taken up on the resin to decrease due to the competition uptakes of hydroxyl ion with taurine or the decrease in the amount of absorbable zwitterions of taurine in the solution and excluding the cations of taurine from the anion resin.展开更多
hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) mat...hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.展开更多
The Parameter identification model is proposed for determining the linear adsorptionisotherms and the solid diffusion coefficients by using adsorption chromatography. Axialdispersion coefficients is firstly determined...The Parameter identification model is proposed for determining the linear adsorptionisotherms and the solid diffusion coefficients by using adsorption chromatography. Axialdispersion coefficients is firstly determined by pulse-respond experiment technique with aninert substance as tracer then the elution curves of chromatography separating the isomermannitol and sorbitol are determined by the chromatographic measuring technique, andfinally the adsorption isotherms and the solid diffusion coefficients of mannitol andsorbitol on Ca2+ resins are estimated by using this model. The results show that the axialdispersion coefficients increase with fluid velocity increasing, the adsorption equilibriumconstants decrease with temperature rising;and the solid diffusion coefficients increasewith temperature rising. The theoretical elution curves are good agreement with theexperimental elution curves of the liquid adsorption chromatography separating themannitol and the sorbitol. The model provides a simple and reliable procedure to estimatethe kinetic and thermodynamic parameters of the adsorption.展开更多
Linear driving force (LDF) model is widely used in a diffusion process. However thismodel has inherent weakness. When the dimensionless time is less than 0.1, its relativeerror is up to 95%. In this paper a new concen...Linear driving force (LDF) model is widely used in a diffusion process. However thismodel has inherent weakness. When the dimensionless time is less than 0.1, its relativeerror is up to 95%. In this paper a new concentration profile is proposed, and then a newmodified LDF model (MLDF) is deduced. Compared with the exact solution ofintraparticle diffusion equation, the transient volume-average amount adsorbedcalculated from the MLDF is more accurate than that calculaled from the LDF modeL .Ifone takes ±10% relative error for the limit of validity of approximation, the new model isvalid when the dimensionless time is just larger than 0. 0002, while the LDF model is notvalid until the dimension time is large than 0.05. The new model is superior to the LDFmodel. The new concentration profiles corresponding to the MLDF model are much closeto the exact concentration profiles within a particle than the parabolic propescorresponding to the LDF model.展开更多
基金The National Natural Scientific Foundation of China. (Project grant No. 29936100)
文摘In this paper, six kinds of activated carbons such as Ag+-activated carbon, Cu2+- activated carbon, Fe3+- activated carbon, activated carbon, Ba2+- activated carbon and Ca2+- activated carbon were prepared. The model for estimating activated energy of desorption was established. Temperature-programmed desorption (TPD) experiments were conducted to measure the TPD curves of n-hexanol and then estimate the activation energy for desorption of n-hexanol on the activated carbons. Results showed that the activation energy for the desorption of n-hexanol on the Ag+- activated carbon, the Cu2+- activated carbon and the Fe3+- activated carbon were higher than those of n-hexanol on the activated carbon, the Ca2+- activated carbon and the Ba2+- activated carbon.
基金The National Natural Science Foundation of China (No. 29936100), and the Natural Science Foundation of Guangdong Province.
文摘Adsorption equilibrium experiments of phenol on the NKA II resin are separately conducted in the presence and absence of ultrasound at ambient temperature. The isotherm of phenol on the polymer adsorbent in the presence of ultrasonic field is firstly reported. Results indicated that the isotherm of phenol determined in the presence of ultrasound is lower than that in the absence of ultrasound. In addition, experiments also show that the use of ultrasound to the adsorption system of the phenol aqueous solution and NKA II resin could cause the rising of the temperature of the system in the order of 6 0C. The effect of ultrasound on the isotherm of the phenol on the NKA II resin mostly ascribes to the thermal effect and the non-thermal effect of ultrasonic field, and the role of the later is greater than that of the former.
文摘In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatography （IGC） in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption （TPD） technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.
文摘Desorption of volatile organic compounds (VOCs) from polymeric adsorbents by microwave was investigated experimentally. Two kinds of organic compounds, benzene and toluene, were separately used as adsorbates in this work. Results showed that the application of microwave to regenerate the polymeric adsorbents not only can get higher regeneration efficiency in comparison with the use of heat regeneration, but also make the temperatures of the fixed beds much lower than that when using the heat regeneration. The weaker the polarity of a polymeric adsorbent, the easier its regeneration was.
基金The National Natural Science Foundation of China (No. 29936100) The Natural Science Foundation of Guangdong Province (No. 990629).
文摘A new model, phase equilibrium-kinetics model (PEKM), for estimation of diffusion coefficient was proposed in this paper. Kinetic experiments of phenol desorption on NKAII resin in the presence and the absence of ultrasound were separately conducted, and diffusion coefficients of phenol within an adsorbent particle were estimated by means of proposed PEKM and classic simplified model. Results show that the use of ultrasound not only changes the phase equilibrium state of NKA II resin/phenol/water system which had been equilibrium at normal condition, but also enhances diffusion of phenol within the resin. The diffusion coefficient of phenol in the resin in the field of ultrasound increases in an order of magnitude in comparison with the diffusion coefficient determined under no ultrasound. Experimental results also indicated that the diffusion coefficients estimated by PEKM were more accurate than that estimated by the classic simplified model.
基金The national Natural Science Foundation of China (No. 20336020) the Doctorate Foundation of the State Education Ministry of China (No.20020561010) The Natural Science Foundation of Guangdong Province of China (No.36566).
文摘CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuOγ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuOγ-Al2O3 catalyst prepared via plasma was much higher than that of the CuOγ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment.
基金Science & Technology Foundation of Guangdong Province of China (No. 2003A3050501)
文摘Studied the effect of ionic strength on the uptake of taurine on a strong-basic anion exchange resin The batch phase equilibrium experiments of taurine on the anion exchange resin D290 were conducted at different ionic strength, and then the amounts of uptake of taurine on the resin at different pH were determined. The ion exchange mechanisms of taurine on the anion exchange resin at different pH were discussed. Experimental results showed that with increase of the ionic strength of solution, the adsorbed amount of taurine on the resin D290 decreased; Adding small amounts of NaOH or HCl into the system of taurine aqueous solution/D290 anion resin would nfake the amount of taurine taken up on the resin to decrease due to the competition uptakes of hydroxyl ion with taurine or the decrease in the amount of absorbable zwitterions of taurine in the solution and excluding the cations of taurine from the anion resin.
基金Plan Project of Science and Technology of Guangzhou City (2002J1-C0061) The First Author: XI Hongxia(1968-)
文摘hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.
文摘The Parameter identification model is proposed for determining the linear adsorptionisotherms and the solid diffusion coefficients by using adsorption chromatography. Axialdispersion coefficients is firstly determined by pulse-respond experiment technique with aninert substance as tracer then the elution curves of chromatography separating the isomermannitol and sorbitol are determined by the chromatographic measuring technique, andfinally the adsorption isotherms and the solid diffusion coefficients of mannitol andsorbitol on Ca2+ resins are estimated by using this model. The results show that the axialdispersion coefficients increase with fluid velocity increasing, the adsorption equilibriumconstants decrease with temperature rising;and the solid diffusion coefficients increasewith temperature rising. The theoretical elution curves are good agreement with theexperimental elution curves of the liquid adsorption chromatography separating themannitol and the sorbitol. The model provides a simple and reliable procedure to estimatethe kinetic and thermodynamic parameters of the adsorption.
文摘Linear driving force (LDF) model is widely used in a diffusion process. However thismodel has inherent weakness. When the dimensionless time is less than 0.1, its relativeerror is up to 95%. In this paper a new concentration profile is proposed, and then a newmodified LDF model (MLDF) is deduced. Compared with the exact solution ofintraparticle diffusion equation, the transient volume-average amount adsorbedcalculated from the MLDF is more accurate than that calculaled from the LDF modeL .Ifone takes ±10% relative error for the limit of validity of approximation, the new model isvalid when the dimensionless time is just larger than 0. 0002, while the LDF model is notvalid until the dimension time is large than 0.05. The new model is superior to the LDFmodel. The new concentration profiles corresponding to the MLDF model are much closeto the exact concentration profiles within a particle than the parabolic propescorresponding to the LDF model.
