Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In...Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.展开更多
To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were investigated.First,the correlation betwe...To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were investigated.First,the correlation between the surface characteristics of four different alumina and the existing Mo species states was established.It was found that the Mo equilibrium adsorption capacity can be used as a specific descriptor to quantitatively evaluate the changes in surface characteristics of different alumina.A lower Mo equilibrium adsorption capacity for alumina means weaker metal-support interaction and the loaded Mo species are easier to transform into MoS2.However,the Mo-O-Al bonds still exist at the metal-support interface.The introduction of cationic surfactant hecadecyl trimethyl ammonium bromide(CTAB)can further improve Mo species dispersion through electrostatic attraction with Mo anions and interaction of its alkyl chain with the alumina surface;meanwhile,the introduction of ethylenediamine tetraacetic acid(EDTA)can complex with Ni ions to enhance the Ni-promoting effect on Mo.Therefore,the NiMo catalyst designed using alumina with lower Mo equilibrium adsorption capacity and the simultaneous addition of EDTA and CTAB exhibits the highest hydrodesulfurization activity for 4,6-dimethyl dibenzothiophene because of its proper metal-support interaction and more well-dispersed Ni-Mo-S active phases.展开更多
The present work was mainly focused on the single and binary adsorption of methylene blue(MB)and methyl orange(MO)from alcohol aqueous solution over rice husk based activated carbon(RHAC).The study of single dye adsor...The present work was mainly focused on the single and binary adsorption of methylene blue(MB)and methyl orange(MO)from alcohol aqueous solution over rice husk based activated carbon(RHAC).The study of single dye adsorption equilibrium experiments found that the Langmuir adsorption model was consistent with the adsorption behavior of RHAC on MB and MO,indicating that it was a single layer adsorption.The adsorption behavior con-formed to the pscudo-second-order kinetic model.The binary dye adsorption experiments showed that the Lang-muir-Freundlich model could be applied to describe the adsorption behavior of RHAC on MB and MO.Comparation with the single dye system,the adsorption capacity on the binary dye system was larger,and there was"competitive adsorption"and"synergistic adsorption"effects existed.Meanwhile,the pseudo-second-order kinetic model also fit for the binary dye adsorption behavior.展开更多
A utility equipment used in soil science is designed and installed.The equipment can be used in research pro- grams of soil water and solute transport.Pressure in pressure chamber of the equipment in which a tested so...A utility equipment used in soil science is designed and installed.The equipment can be used in research pro- grams of soil water and solute transport.Pressure in pressure chamber of the equipment in which a tested soil sam- ple is laid can be adjusted exactly so that we can determine the water content of soil sample.With the equipment we can not only study the problems related water movement in soil but also measure some solute,such as cadmi- um,plumbum and so on,adsorption on surface of soil in saturated and unsaturated state.As an illustration of the use of the equipment,we give the isothermal of cupric ion adsorption in soil.This equipment can be used in the re- search work and application of soil science.展开更多
Spherical particles of α-,β- and γ-cyclodextrin (CD) polymers to efficiently remove phenol from waste water were prepared by reverse suspension polymerization with epichlorohydrin as crosslinker in liquid paraffi...Spherical particles of α-,β- and γ-cyclodextrin (CD) polymers to efficiently remove phenol from waste water were prepared by reverse suspension polymerization with epichlorohydrin as crosslinker in liquid paraffin. By controlling the amounts of crosslinker and water, well- defined spherical polymer particles with controllable size were obtained. Due to the selective inclusion associations between CD groups and phenol, these CD spherical polymer particles were demonstrated to be ideal candidates for removal of phenol. Among them β-CD polymer particles showed the best performance. The kinetics and isothermal equilibrium models were used to fit the experimental data of phenol removal from aqueous solution using these CD polymer particles. It was found that the kinetics followed the Ho and Mckay equation, suggesting that the adsorption process of phenol was controlled by diffusion and the host-guest interaction between CD and phenol. Equilibrium isothermal data can be well fitted by the Freundlich equation. The negative free energy change indicated the spontaneous nature of adsorption of phenol by α-,β- and γ-CD spherical polymer particles, while the lowest free energy for β-CD polymer reflected its best adsorption ability, compared to α- and γ- CD polymer particles.展开更多
In this work,the effect of the textural property of activated carbons on desorption activation energy and adsorption capacity for benzothiophene(BT)was investigated.BET surface areas and the textural parameters of thr...In this work,the effect of the textural property of activated carbons on desorption activation energy and adsorption capacity for benzothiophene(BT)was investigated.BET surface areas and the textural parameters of three kinds of the activated carbons,namely SY-6,SY-13 and SY-19,were measured with an ASAP 2010 instrument.The desorption activation energies of BT on the activated carbons were determined by temperature-programmed desorption(TPD).Static adsorption experiments were carried out to determine the isotherms of BT on the activated carbons.The influence of the textural property of the activated carbons on desorption activation energy and the adsorption capacity for BT was discussed.Results showed that the BET surface areas of the activated carbons,SY-6,SY-13 and SY-19 were 1106,1070 and 689 m2·g^(-1),respectively,and their average pore diameters were 1.96,2.58 and 2.16 nm,respectively.The TPD results indicated that the desorption activation energy of BT on the activated carbons,SY-6,SY-19 and SY-13 were 58.84,53.02 and 42.57 KJ/mol,respectively.The isotherms showed that the amount of BT adsorbed on the activated carbons followed the order of SY-6>SY-19>SY-13.The smaller the average pore diameter of the activated carbon,the stronger its adsorption for BT and the higher the activation energy required for BT desorption on its surface.The Freundlich adsorption isotherm model can be properly used to formulate the adsorption behavior of BT on the activated carbons.展开更多
TiO2 particles with desirable properties were produced by undergoing specific durations of ball milling.Characterizations of the TiO2 particles before and after ball milling were investigated via X-ray diffraction(XR...TiO2 particles with desirable properties were produced by undergoing specific durations of ball milling.Characterizations of the TiO2 particles before and after ball milling were investigated via X-ray diffraction(XRD), Brunauer-Emmett-Teller(BET), particle size analysis, zeta potential, and scanning electron microscope(SEM). The equilibrium adsorption data were well fitted to Langmuir, Freundlich, and Dubinin-Radushkevich(D-R) isotherms. Compared to the as-received TiO2(mean particle size d150= 0.78μm, specific surface area = 88.17 m^2g-1, pore volume = 0.41 cm^3g-1), the 60 min ballmilled TiO2(d50= 0.55 μm, specific surface area = 99.48 m2g-1, pore volume = 0.48 cm3g-1) enhanced the adsorption quantity of congo red and methylene blue from 10.4 mg g-1to 13.6 mg g-1, and from17.0 mg g-1to 22.2 mg g-1, respectively; and also improved the kinetic rates from k = 0.1325 to 0.2193, and k = 0.0944 to 0.1553, respectively. Dye adsorption and degradation efficiency of congo red was enhanced in acidic p H range(2–5.14), and methylene blue was enhanced in alkaline p H range(7.58–12).展开更多
In this study, cucurbit[8]uril (CB[8]) was utilized as a kind of new adsorbent to remove Pb^2+ ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased ...In this study, cucurbit[8]uril (CB[8]) was utilized as a kind of new adsorbent to remove Pb^2+ ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb^2+ increased rapidly in the initial 30 min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb^2+ adsorption onto CB[8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67 mg/g for 298 K, 149.70 mg/g for 313 K and 136.42 mg/g for 323 K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB[8] was synthesized and characterized by 1H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB[8] molecule and Pb^2+ ions.展开更多
基金supported by the renewable energy and hydrogen projects in National Key Research and Development Plan of China(2019YFB1505000).
文摘Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.
基金funding of the National Key Research and Development Plan(Grant 2017YFB0306600)the Project of SINOPEC(NO.117006).
文摘To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were investigated.First,the correlation between the surface characteristics of four different alumina and the existing Mo species states was established.It was found that the Mo equilibrium adsorption capacity can be used as a specific descriptor to quantitatively evaluate the changes in surface characteristics of different alumina.A lower Mo equilibrium adsorption capacity for alumina means weaker metal-support interaction and the loaded Mo species are easier to transform into MoS2.However,the Mo-O-Al bonds still exist at the metal-support interface.The introduction of cationic surfactant hecadecyl trimethyl ammonium bromide(CTAB)can further improve Mo species dispersion through electrostatic attraction with Mo anions and interaction of its alkyl chain with the alumina surface;meanwhile,the introduction of ethylenediamine tetraacetic acid(EDTA)can complex with Ni ions to enhance the Ni-promoting effect on Mo.Therefore,the NiMo catalyst designed using alumina with lower Mo equilibrium adsorption capacity and the simultaneous addition of EDTA and CTAB exhibits the highest hydrodesulfurization activity for 4,6-dimethyl dibenzothiophene because of its proper metal-support interaction and more well-dispersed Ni-Mo-S active phases.
基金Supported by the National Natural Science Foundation of China(No.21501069)the National Key R&D Program During the 13th Five-year Plan of China(No.2016YFD0401405)+1 种基金the Fundamental Research Funds for the Central Universities of China(No.JUSRP51626B)MOE&SAFEA for the"111 Project"of China(No.B13025).
文摘The present work was mainly focused on the single and binary adsorption of methylene blue(MB)and methyl orange(MO)from alcohol aqueous solution over rice husk based activated carbon(RHAC).The study of single dye adsorption equilibrium experiments found that the Langmuir adsorption model was consistent with the adsorption behavior of RHAC on MB and MO,indicating that it was a single layer adsorption.The adsorption behavior con-formed to the pscudo-second-order kinetic model.The binary dye adsorption experiments showed that the Lang-muir-Freundlich model could be applied to describe the adsorption behavior of RHAC on MB and MO.Comparation with the single dye system,the adsorption capacity on the binary dye system was larger,and there was"competitive adsorption"and"synergistic adsorption"effects existed.Meanwhile,the pseudo-second-order kinetic model also fit for the binary dye adsorption behavior.
文摘A utility equipment used in soil science is designed and installed.The equipment can be used in research pro- grams of soil water and solute transport.Pressure in pressure chamber of the equipment in which a tested soil sam- ple is laid can be adjusted exactly so that we can determine the water content of soil sample.With the equipment we can not only study the problems related water movement in soil but also measure some solute,such as cadmi- um,plumbum and so on,adsorption on surface of soil in saturated and unsaturated state.As an illustration of the use of the equipment,we give the isothermal of cupric ion adsorption in soil.This equipment can be used in the re- search work and application of soil science.
文摘Spherical particles of α-,β- and γ-cyclodextrin (CD) polymers to efficiently remove phenol from waste water were prepared by reverse suspension polymerization with epichlorohydrin as crosslinker in liquid paraffin. By controlling the amounts of crosslinker and water, well- defined spherical polymer particles with controllable size were obtained. Due to the selective inclusion associations between CD groups and phenol, these CD spherical polymer particles were demonstrated to be ideal candidates for removal of phenol. Among them β-CD polymer particles showed the best performance. The kinetics and isothermal equilibrium models were used to fit the experimental data of phenol removal from aqueous solution using these CD polymer particles. It was found that the kinetics followed the Ho and Mckay equation, suggesting that the adsorption process of phenol was controlled by diffusion and the host-guest interaction between CD and phenol. Equilibrium isothermal data can be well fitted by the Freundlich equation. The negative free energy change indicated the spontaneous nature of adsorption of phenol by α-,β- and γ-CD spherical polymer particles, while the lowest free energy for β-CD polymer reflected its best adsorption ability, compared to α- and γ- CD polymer particles.
基金the National Natural Science Foundation of China(Grant No.20336020)for financial support.
文摘In this work,the effect of the textural property of activated carbons on desorption activation energy and adsorption capacity for benzothiophene(BT)was investigated.BET surface areas and the textural parameters of three kinds of the activated carbons,namely SY-6,SY-13 and SY-19,were measured with an ASAP 2010 instrument.The desorption activation energies of BT on the activated carbons were determined by temperature-programmed desorption(TPD).Static adsorption experiments were carried out to determine the isotherms of BT on the activated carbons.The influence of the textural property of the activated carbons on desorption activation energy and the adsorption capacity for BT was discussed.Results showed that the BET surface areas of the activated carbons,SY-6,SY-13 and SY-19 were 1106,1070 and 689 m2·g^(-1),respectively,and their average pore diameters were 1.96,2.58 and 2.16 nm,respectively.The TPD results indicated that the desorption activation energy of BT on the activated carbons,SY-6,SY-19 and SY-13 were 58.84,53.02 and 42.57 KJ/mol,respectively.The isotherms showed that the amount of BT adsorbed on the activated carbons followed the order of SY-6>SY-19>SY-13.The smaller the average pore diameter of the activated carbon,the stronger its adsorption for BT and the higher the activation energy required for BT desorption on its surface.The Freundlich adsorption isotherm model can be properly used to formulate the adsorption behavior of BT on the activated carbons.
文摘TiO2 particles with desirable properties were produced by undergoing specific durations of ball milling.Characterizations of the TiO2 particles before and after ball milling were investigated via X-ray diffraction(XRD), Brunauer-Emmett-Teller(BET), particle size analysis, zeta potential, and scanning electron microscope(SEM). The equilibrium adsorption data were well fitted to Langmuir, Freundlich, and Dubinin-Radushkevich(D-R) isotherms. Compared to the as-received TiO2(mean particle size d150= 0.78μm, specific surface area = 88.17 m^2g-1, pore volume = 0.41 cm^3g-1), the 60 min ballmilled TiO2(d50= 0.55 μm, specific surface area = 99.48 m2g-1, pore volume = 0.48 cm3g-1) enhanced the adsorption quantity of congo red and methylene blue from 10.4 mg g-1to 13.6 mg g-1, and from17.0 mg g-1to 22.2 mg g-1, respectively; and also improved the kinetic rates from k = 0.1325 to 0.2193, and k = 0.0944 to 0.1553, respectively. Dye adsorption and degradation efficiency of congo red was enhanced in acidic p H range(2–5.14), and methylene blue was enhanced in alkaline p H range(7.58–12).
基金support provided by the National Nature Science Foundation of China (Nos. 51208179, 21202037)the Doctor Fund of Henan University of Technology (No. 2013BS066)
文摘In this study, cucurbit[8]uril (CB[8]) was utilized as a kind of new adsorbent to remove Pb^2+ ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb^2+ increased rapidly in the initial 30 min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb^2+ adsorption onto CB[8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67 mg/g for 298 K, 149.70 mg/g for 313 K and 136.42 mg/g for 323 K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB[8] was synthesized and characterized by 1H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB[8] molecule and Pb^2+ ions.