A continuous stirred-tank reactor （CSTR） process with granular activated carbon （GAC） was developed for fermentation hydrogen production from molasses-containing wastewater by mixed microbial cultures. Operation a...A continuous stirred-tank reactor （CSTR） process with granular activated carbon （GAC） was developed for fermentation hydrogen production from molasses-containing wastewater by mixed microbial cultures. Operation at 35℃, an initial biomass of 17.74 g·L^-1 and hydraulic retention time （HRT） of 6 h, the CSTR reactor presented a continuous hydrogen production ability of 5.9 L·d^-1 and the biogas was free of methane throughout the experiment. Dissolved fermehtation products were predominated by ethanol and acetate acid, with smaller quantities of propionic acid, butyric acid and valeric acid. It was found that GAC could make the immobilized system durable and stable in response to organic load impacting and low pH value. When the organic loading rate （OLR） ranged from 8 kgCOD/（m^3d） to 4 kgCOD/（m^3d）, stable ethanol-type fermentation was formed, and the ethanol and acetate concentrations account for 89% of the total liquid products.展开更多
Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer...Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.展开更多
XPS(X-ray photoelectron spectroscopy) spectrometer EscA-750 was used to analyse the surface character of activated carbon, magnetic reagent and magnetic activated carbon. The distribution and change of C valence of th...XPS(X-ray photoelectron spectroscopy) spectrometer EscA-750 was used to analyse the surface character of activated carbon, magnetic reagent and magnetic activated carbon. The distribution and change of C valence of them were determined. The conclusion is that the magnetic reagent could be adsorbed on the surface of activated carbon chemically. the interpretation of adsorptive mechanism of magnetic reagent in microstructure was discussed.展开更多
Based on the special molccular structure of surfactant paramagnctic material used as magnetic nucleus wascoated with two layers of surfactant inculding an inner layer and an outer layer and an outer layer Magnetic rea...Based on the special molccular structure of surfactant paramagnctic material used as magnetic nucleus wascoated with two layers of surfactant inculding an inner layer and an outer layer and an outer layer Magnetic reagent can combine with activated carbon due to adsorption of hydrophilic raclical of the outer surfactant layer so activated carbon has magnetism Theeffects of magnetic reagent dosage. pH and activator upon the magnetic susceptibility of activated carbon were studied.Conceming the optimal conditions. MR-20 is the best magnetic reagent. Concentration of CaCl2 is 0.02M and pH1.8-2.4The physical properties of magnetic activated carbon vary with the types dosage and magnetizing condition of magneticreagent.展开更多
Numerous researches were reviewed and interpreted to depict a comprehensive illustration of activated carbon and its behavior towards oxidation.Activated carbon as one of the most important adsorbents is tried to be d...Numerous researches were reviewed and interpreted to depict a comprehensive illustration of activated carbon and its behavior towards oxidation.Activated carbon as one of the most important adsorbents is tried to be described in this review paper by terms of its＂Textural Characteristics＂and＂Surface Chemistry＂.These two terms,coupled with each other,are responsible for behavior of activated carbon in adsorption processes and in catalytic applications.Although as-prepared activated carbons are usually nonselective and their surfaces suffer from lack of enough reactive groups,their different aspects may be improved and developed by diverse types of modifications.Oxidation is one of the most conventional modifications used for activated carbons.It may be used as a final modification or as a pre-modification followed by further treatment.In this paper,methods of oxidation of activated carbon and other graphene-layer carbon materials are introduced and wet oxidation as an extensively-used category of oxidation is discussed in more detail.展开更多
Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly ...Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces. The texture property test reveals that the activated carbons displayed different texture properties, especially the micropore size distribution. The adsorption capacities of the activated carbons were investigated by adsorbing CH4, CO2, N2 and O2 at 25 ？C in the pressure range of 0-200 kPa. The results reveal that all the activated carbons had high CO2 adsorption capacity, one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa. And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa. In the pressure range of 0-200 kPa, the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.展开更多
The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a v...The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus in order to obtain more information about the effect of CO2 on removal of organic sulfur-containing compounds in industrial gases. The active ingredients impregnated in the carbon samples show significant influence on the adsorption for CO2 and its volumes adsorbed on modified carbon samples B, C, and D are all larger than that on the raw carbon sample A. On the other hand, the physical parameters such as surface area, pore volume, and micropore volume of carbon samples show no influence on the adsorbed amount of CO2. The Dubinin-Radushkevich （D-R） equation was the best model for fitting the adsorption data on carbon samples A and B, while the Freundlich equation was the best fit for the adsorption on carbon samples C and D. The isosteric heats of adsorption on carbon samples A, B, C, and D derived from the adsorption isotherms using the Clapeyron equation decreased slightly increasing surface loading. The heat of adsorption lay between 10.5 and 28.4 kJ/mol, with the carbon sample D having the highest value at all surface coverages that were studied. The observed entropy change associated with the adsorption for the carbon samples A, B, and C （above the surface coverage of 7 ml/g） was lower than the theoretical value for mobile adsorption. However, it was higher than the theoretical value for mobile adsorption but lower than the theoretical value for localized adsorption for carbon sample D.展开更多
The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great co...The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries.展开更多
Coal-based Magnetic Activated Carbons （CMAC＇s） were prepared from three representative coal samples of various ranks： Baorigele lignite from Inner Mongolia; Datong bitumite from Shanxi province; and Taixi anthraci...Coal-based Magnetic Activated Carbons （CMAC＇s） were prepared from three representative coal samples of various ranks： Baorigele lignite from Inner Mongolia; Datong bitumite from Shanxi province; and Taixi anthracite from Ningxia Hui Auto- nomous Region. Fe3O4 was used as a magnetic additive. A nitrogen-adsorption analyzer was used to determine the specific surface area and pore structure of the resulting activated carbons. The adsorption capacity was assessed by the adsorption of iodine and methylene blue. X-ray diffraction was used to measure the evolution behavior of Fe304 during the preparation process. Magnetic properties were characterized with a vibrating-sample magnetometer. The effect of the activation temperature on the performance of CMAC＇s was also studied. The results show that, compared to Baorigele lignite and Taixi anthracite, the Datong bitumite is more appropriate for the preparation of CMAC＇s with a high specific surface area, an advanced pore structure and suitable magnetic properties. Fe304 can effectively enhance the magnetic properties and control the pore structure by increasing the ratio of meso- pores. An addition of 6.0% Fe304 and an activation temperature of 880 ℃ produced a CMAC having a specific surface area, an iodine adsorption, a methylene blue adsorption and a specific saturation magnetization of 1152.0 m2/g, 1216.7 mg/g, 229.5 mg/g and 4.623 emu/g, respectively. The coal used to prepare this specimen was Datong bitumite.展开更多
To investigate the effects of carbon surface characteristics on NH3 adsorption,coal-based and coconut shell activated carbons were modified by treatment with oxidants.The surface properties of the carbons were charact...To investigate the effects of carbon surface characteristics on NH3 adsorption,coal-based and coconut shell activated carbons were modified by treatment with oxidants.The surface properties of the carbons were characterized by low temperature nitrogen sorption,by Boehm's titrations and by XPS techniques.NH3 adsorption isotherms of the original and the modified carbons were determined.The results show that the carbons were oxidized by HNO3 and(NH4)2S2O8,and that there was an increase in oxygen containing functional groups on the surface.However,the pore-size distribution of the coal-based carbons was changed after KMnO4 treatment.It was found that the NH3 adsorption capacity of the modified carbons was enhanced and that the most pronounced enhancement results from(NH4)2S2O8 oxidation.Under our experimental conditions,the capacity is positively cor- rected to the number of surface functional groups containing oxygen,and to the number of micro-pores.Furthermore,an empirical model of the relationship between NH3 adsorption and multiple factors on the carbon surface was fit using a complex regression method.展开更多
Activated carbons derived from corncob （CACs） were prepared by pyrolysis carbonization and KOH activation. Through modifying activation conditions, samples with large pore volume and ultrahigh BET specific surface a...Activated carbons derived from corncob （CACs） were prepared by pyrolysis carbonization and KOH activation. Through modifying activation conditions, samples with large pore volume and ultrahigh BET specific surface area could be obtained. The sample achieved the highest hydrogen uptake capacity of 5.80 wt% at 40 bar and -196℃ The as-obtained samples were characterized by N2-sorption, transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. Besides, thermogravimetric analysis was also employed to investigate the activation behavior of CACs. Detailed investigation on the activation parameters reveals that moderate activation temperature and heating rate are favorable for preparing CACs with high surface area, large pore volume and optimal pore size distribution. Meanwhile, the micropore volume between 0.65 nm and 0.85 nm along with BET surface area and total pore volume has great effects on hydrogen uptake capacities. The present results indicate that CACs are the most promising materials for hydrogen storage application.展开更多
Supported coupling catalysts for CS2 removal were prepared with different activated carbons originated from wood,coconut shell and coal as supports,and their catalytic activities for CS2 removal were tested at ambient...Supported coupling catalysts for CS2 removal were prepared with different activated carbons originated from wood,coconut shell and coal as supports,and their catalytic activities for CS2 removal were tested at ambient temperature.The textural and surface properties of the activated carbons were characterized by nitrogen adsorption,temperature-programmed desorption（TPD）and Boehm titration.The activated carbon support with meso-and macropores,and oxygen-functional groups performs higher CS2 removal ability at ambient temperature.The effects of flow rate,CS2 inlet concentration,temperature and relative humidity on CS2 removal were also investigated.High efficient removal is obtained at temperature of 50-C,space velocity of 2000 h-1,inlet CS2 concentration of 500 mgS/m3 and relative humidity of 20%with the breakthrough sulfur capacity up to 4.3 gS/gCat and working sulfur capacity up to 7 gS/gCat.展开更多
Mesoporous activated carbons were prepared from direct coal liquefaction residue （CLR） by KOH activation method, and the experiments were carried out to investigate the effects of KOH/CLR ratio, solvent for mixing t...Mesoporous activated carbons were prepared from direct coal liquefaction residue （CLR） by KOH activation method, and the experiments were carried out to investigate the effects of KOH/CLR ratio, solvent for mixing the CLR and KOH, and carbonization procedure on the resultant carbon texture and catalytic activity for catalytic methane decomposition （CMD）. The results showed that optimal KOH/CLR ratio of 2 ： 1; solvent with higher solubility to KOH or the CLR, and an appropriate carbonization procedure are conductive to improving the carbon pore structure and catalytic activity for CMD. The resultant mesoporous carbons show higher and more stable activity than microporous carbons. Additionally, the relationship between the carbon textural properties and the catalytic activity for CMD was also discussed.展开更多
Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous r...Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous reduction of zinc-bearing dusts and activation of low-rank coal was developed and its mechanism was clarified in this paper.Under the optimal conditions,the reduced zinc-bearing dusts containing low harmful elements(0.02%Zn,0.015%K and 0.03%Na)could be made as high-quality burden for blast furnace while the low-rank coal was transferred into K,Na-embedded activated carbon,which can be used as effective adsorbent for purification of SO_(2) and NO-containing flue gases.The solid wastes were successfully utilized to treat the flue gases through the process.The synergetic activation and reduction mechanism in the process was revealed.The coupling effect between reduction reactions of metal oxides in the dusts and activation reaction of carbon in the coal promoted the simultaneous reduction and activation process.In the meanwhile,part of the potassium and sodium from the zinc-bearing dusts could be adsorbed by the activated carbon and played a catalytic role in the activation process.展开更多
A theoretical and experimental study was conducted to accurately determine the amount of adsorption and desorption of methane by various Granular Activated Carbon （GAC） under different physical conditions. To carry ...A theoretical and experimental study was conducted to accurately determine the amount of adsorption and desorption of methane by various Granular Activated Carbon （GAC） under different physical conditions. To carry out the experiments, the volumetric method was used up to 500 psia at constant temperature of 25℃. In these experiments, adsorption as well as desorption capacities of four different GAC in the adsorption of methane, the major constituent of natural gas, at various equilibrium pressures and a constant temperature were studied. Also, various adsorption isotherm models were used to model the experimental data collected from the experiments. The accuracy of the results obtained from the adsorption isotherm models was compared and the values for the regressed parameters were reported. The results shows that the physical characteristics of activated carbons such as BET surface area, micropore volume, packing density, and pore size distribution play an important role in the amount of methane to be adsorbed and desorbed.展开更多
Nitrogen-containing carbons were prepared by modification of activated carbons.The modified carbons were used as electrode materials with improved electrochemical performance.Precursor anthracite was activated by KOH(...Nitrogen-containing carbons were prepared by modification of activated carbons.The modified carbons were used as electrode materials with improved electrochemical performance.Precursor anthracite was activated by KOH(KOH:anthracite= 1:1), modified by melamine or urea and then treated at 1173 K to obtain the modified carbons.The porous structure, the chemical composition and the electrochemical characteristics of the carbons were investigated by nitrogen sorption, XPS and electrochemical methods respectively.Electrochemical experiments were performed in an organic electrolytic solution of 1 M(C2H5)4NBF4/PC.The samples modified by the different methods showed differences in chemical composition that introduced varying degrees of electrochemical performance enhancement.The presence of nitrogen enhanced the electron donor properties and the surface wettability of the activated carbons:this ensured a sufficient utilization of the exposed surface for charge storage.展开更多
Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and cataly...Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasmatreated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.展开更多
In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activa...In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2 adsorption-desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO_(3))3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m^(2)/g to 685.90 m^(2)/g,and then decreased to 299.56 m^(2)/g.The total pore volume and micropore volume increased from 0.29 cm^(3)/g and 0.17 cm^(3)/g to 0.30 cm^(3)/g and 0.22 cm^(3)/g,and then decreased to 0.16 cm^(3)/g and 0.10 cm^(3)/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume(685.90 m^(2)/g and 0.30 cm^(3)/g)were formed under the optimized activation conditions(950℃,20%(volume)of CO_(2),ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.展开更多
Adsorption and desorption of methane by activated carbon （AC） at constant temperature and at various pressures were investigated. The effect of moisture was also studied. A volumetric method was used, up to 40 bar, ...Adsorption and desorption of methane by activated carbon （AC） at constant temperature and at various pressures were investigated. The effect of moisture was also studied. A volumetric method was used, up to 40 bar, at a temperature of 273.5 K. Results of a dry AC sample were compared with those obtained from a moist sample and two different ACs with different physical and surface properties were used. As expected, the results showed that the existence of moisture, trapped in the AC pores, could lead to a decrease in the amount of methane adsorbed and a decrease in the amount of methane delivered during desorption. To model the experimental results, a large variety of adsorption isotherms were used. The regressed parameters for the adsorption isotherms were obtained using the experimental data generated in the present study. The accuracy of the results obtained from the different adsorption isotherms was favorably compared.展开更多
The hierarchical nanostructured N-doped TiO2 immobilized activated carbon fiber(N-TiO2/ACF)porous composites are fabricated to removal dynamic toluene gas.The results show that nitrogen ions doping and ACF modificatio...The hierarchical nanostructured N-doped TiO2 immobilized activated carbon fiber(N-TiO2/ACF)porous composites are fabricated to removal dynamic toluene gas.The results show that nitrogen ions doping and ACF modification can decrease the band gap of TiO2,leading to red shift toward visible light region.Interestingly,N-TiO2/ACF exhibits strongly synergistic effect owing to high surface area,good crystallinity,enhanced bandgap structure and light harvesting.The toluene removal rate of N-TiO2/ACF composites is 2.29 times higher than that of TiO2.The N-TiO2/ACF for toluene degradation followed the Langmuir-Hinshelwood kinetic model,and the rate constant is enhanced 8 times compared with TiO2.The possible photodegradation pathway and mechanisms are proposed.展开更多
基金supported by the National Hi-Tech R&D Program (863 Program)Ministry of Science&Technology, China (Grant No. 2006AA05Z109)+1 种基金Shanghai Science and Technology Bureau (Grant No.071605122)Educated programme of excellent doctor of Southeast Forestry University (GRAP09)
文摘A continuous stirred-tank reactor （CSTR） process with granular activated carbon （GAC） was developed for fermentation hydrogen production from molasses-containing wastewater by mixed microbial cultures. Operation at 35℃, an initial biomass of 17.74 g·L^-1 and hydraulic retention time （HRT） of 6 h, the CSTR reactor presented a continuous hydrogen production ability of 5.9 L·d^-1 and the biogas was free of methane throughout the experiment. Dissolved fermehtation products were predominated by ethanol and acetate acid, with smaller quantities of propionic acid, butyric acid and valeric acid. It was found that GAC could make the immobilized system durable and stable in response to organic load impacting and low pH value. When the organic loading rate （OLR） ranged from 8 kgCOD/（m^3d） to 4 kgCOD/（m^3d）, stable ethanol-type fermentation was formed, and the ethanol and acetate concentrations account for 89% of the total liquid products.
基金National Natural Science Foundation of China(Nos.20576079,20776159)
文摘Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.
文摘XPS(X-ray photoelectron spectroscopy) spectrometer EscA-750 was used to analyse the surface character of activated carbon, magnetic reagent and magnetic activated carbon. The distribution and change of C valence of them were determined. The conclusion is that the magnetic reagent could be adsorbed on the surface of activated carbon chemically. the interpretation of adsorptive mechanism of magnetic reagent in microstructure was discussed.
文摘Based on the special molccular structure of surfactant paramagnctic material used as magnetic nucleus wascoated with two layers of surfactant inculding an inner layer and an outer layer and an outer layer Magnetic reagent can combine with activated carbon due to adsorption of hydrophilic raclical of the outer surfactant layer so activated carbon has magnetism Theeffects of magnetic reagent dosage. pH and activator upon the magnetic susceptibility of activated carbon were studied.Conceming the optimal conditions. MR-20 is the best magnetic reagent. Concentration of CaCl2 is 0.02M and pH1.8-2.4The physical properties of magnetic activated carbon vary with the types dosage and magnetizing condition of magneticreagent.
文摘Numerous researches were reviewed and interpreted to depict a comprehensive illustration of activated carbon and its behavior towards oxidation.Activated carbon as one of the most important adsorbents is tried to be described in this review paper by terms of its＂Textural Characteristics＂and＂Surface Chemistry＂.These two terms,coupled with each other,are responsible for behavior of activated carbon in adsorption processes and in catalytic applications.Although as-prepared activated carbons are usually nonselective and their surfaces suffer from lack of enough reactive groups,their different aspects may be improved and developed by diverse types of modifications.Oxidation is one of the most conventional modifications used for activated carbons.It may be used as a final modification or as a pre-modification followed by further treatment.In this paper,methods of oxidation of activated carbon and other graphene-layer carbon materials are introduced and wet oxidation as an extensively-used category of oxidation is discussed in more detail.
基金supported by the National Natural Science Foundation of China(Grant 20773090)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant 200806100009)
文摘Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces. The texture property test reveals that the activated carbons displayed different texture properties, especially the micropore size distribution. The adsorption capacities of the activated carbons were investigated by adsorbing CH4, CO2, N2 and O2 at 25 ？C in the pressure range of 0-200 kPa. The results reveal that all the activated carbons had high CO2 adsorption capacity, one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa. And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa. In the pressure range of 0-200 kPa, the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.
基金National Basic Research Program of China (2005CB221203).
文摘The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus in order to obtain more information about the effect of CO2 on removal of organic sulfur-containing compounds in industrial gases. The active ingredients impregnated in the carbon samples show significant influence on the adsorption for CO2 and its volumes adsorbed on modified carbon samples B, C, and D are all larger than that on the raw carbon sample A. On the other hand, the physical parameters such as surface area, pore volume, and micropore volume of carbon samples show no influence on the adsorbed amount of CO2. The Dubinin-Radushkevich （D-R） equation was the best model for fitting the adsorption data on carbon samples A and B, while the Freundlich equation was the best fit for the adsorption on carbon samples C and D. The isosteric heats of adsorption on carbon samples A, B, C, and D derived from the adsorption isotherms using the Clapeyron equation decreased slightly increasing surface loading. The heat of adsorption lay between 10.5 and 28.4 kJ/mol, with the carbon sample D having the highest value at all surface coverages that were studied. The observed entropy change associated with the adsorption for the carbon samples A, B, and C （above the surface coverage of 7 ml/g） was lower than the theoretical value for mobile adsorption. However, it was higher than the theoretical value for mobile adsorption but lower than the theoretical value for localized adsorption for carbon sample D.
基金financial support from the National Natural Science Foundation of China(grant no.21406052the Program for the Outstanding Young Talents of Hebei Province(grant no.BJ2014010)the Scientific Research Foundation for Selected Overseas Chinese Scholars,Ministry of Human Resources and Social Security of China(grant no.CG2015003002)
文摘The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries.
基金supported by the National Natural Science Foundation of China (No20776150)the National High Technology Research and Development Program of China (No2008AA05Z308)
文摘Coal-based Magnetic Activated Carbons （CMAC＇s） were prepared from three representative coal samples of various ranks： Baorigele lignite from Inner Mongolia; Datong bitumite from Shanxi province; and Taixi anthracite from Ningxia Hui Auto- nomous Region. Fe3O4 was used as a magnetic additive. A nitrogen-adsorption analyzer was used to determine the specific surface area and pore structure of the resulting activated carbons. The adsorption capacity was assessed by the adsorption of iodine and methylene blue. X-ray diffraction was used to measure the evolution behavior of Fe304 during the preparation process. Magnetic properties were characterized with a vibrating-sample magnetometer. The effect of the activation temperature on the performance of CMAC＇s was also studied. The results show that, compared to Baorigele lignite and Taixi anthracite, the Datong bitumite is more appropriate for the preparation of CMAC＇s with a high specific surface area, an advanced pore structure and suitable magnetic properties. Fe304 can effectively enhance the magnetic properties and control the pore structure by increasing the ratio of meso- pores. An addition of 6.0% Fe304 and an activation temperature of 880 ℃ produced a CMAC having a specific surface area, an iodine adsorption, a methylene blue adsorption and a specific saturation magnetization of 1152.0 m2/g, 1216.7 mg/g, 229.5 mg/g and 4.623 emu/g, respectively. The coal used to prepare this specimen was Datong bitumite.
基金Project 2001AA527010-01 supported by the National High Technology Research and Development Program of China
文摘To investigate the effects of carbon surface characteristics on NH3 adsorption,coal-based and coconut shell activated carbons were modified by treatment with oxidants.The surface properties of the carbons were characterized by low temperature nitrogen sorption,by Boehm's titrations and by XPS techniques.NH3 adsorption isotherms of the original and the modified carbons were determined.The results show that the carbons were oxidized by HNO3 and(NH4)2S2O8,and that there was an increase in oxygen containing functional groups on the surface.However,the pore-size distribution of the coal-based carbons was changed after KMnO4 treatment.It was found that the NH3 adsorption capacity of the modified carbons was enhanced and that the most pronounced enhancement results from(NH4)2S2O8 oxidation.Under our experimental conditions,the capacity is positively cor- rected to the number of surface functional groups containing oxygen,and to the number of micro-pores.Furthermore,an empirical model of the relationship between NH3 adsorption and multiple factors on the carbon surface was fit using a complex regression method.
基金supported by the National High Technology Research and Development Program of China(863 Program)(2012AA053305)the International Cooperation Project from Ministry of Science and Technology of China(2010DFA64080)
文摘Activated carbons derived from corncob （CACs） were prepared by pyrolysis carbonization and KOH activation. Through modifying activation conditions, samples with large pore volume and ultrahigh BET specific surface area could be obtained. The sample achieved the highest hydrogen uptake capacity of 5.80 wt% at 40 bar and -196℃ The as-obtained samples were characterized by N2-sorption, transmission electron microscopy （TEM） and scanning electron microscopy （SEM）. Besides, thermogravimetric analysis was also employed to investigate the activation behavior of CACs. Detailed investigation on the activation parameters reveals that moderate activation temperature and heating rate are favorable for preparing CACs with high surface area, large pore volume and optimal pore size distribution. Meanwhile, the micropore volume between 0.65 nm and 0.85 nm along with BET surface area and total pore volume has great effects on hydrogen uptake capacities. The present results indicate that CACs are the most promising materials for hydrogen storage application.
基金financially supported by the National Basic Research Program of China(2010CB732300)the National Key Technologies R&D Program of China(2007BAJ03B01)
文摘Supported coupling catalysts for CS2 removal were prepared with different activated carbons originated from wood,coconut shell and coal as supports,and their catalytic activities for CS2 removal were tested at ambient temperature.The textural and surface properties of the activated carbons were characterized by nitrogen adsorption,temperature-programmed desorption（TPD）and Boehm titration.The activated carbon support with meso-and macropores,and oxygen-functional groups performs higher CS2 removal ability at ambient temperature.The effects of flow rate,CS2 inlet concentration,temperature and relative humidity on CS2 removal were also investigated.High efficient removal is obtained at temperature of 50-C,space velocity of 2000 h-1,inlet CS2 concentration of 500 mgS/m3 and relative humidity of 20%with the breakthrough sulfur capacity up to 4.3 gS/gCat and working sulfur capacity up to 7 gS/gCat.
基金supported by the National Natural Science Foundation of China(No.20906009)the Key Program Project of Joint Fund of Coal Research by NSFC and Shenhua Group(No.51134014)+2 种基金the Fundamental Research Funds for the Central Universities(No.DUT12JN05)the National Basic Research Program of China(973Program)the Ministry of Science and Technology,China(No.2011CB201301)
文摘Mesoporous activated carbons were prepared from direct coal liquefaction residue （CLR） by KOH activation method, and the experiments were carried out to investigate the effects of KOH/CLR ratio, solvent for mixing the CLR and KOH, and carbonization procedure on the resultant carbon texture and catalytic activity for catalytic methane decomposition （CMD）. The results showed that optimal KOH/CLR ratio of 2 ： 1; solvent with higher solubility to KOH or the CLR, and an appropriate carbonization procedure are conductive to improving the carbon pore structure and catalytic activity for CMD. The resultant mesoporous carbons show higher and more stable activity than microporous carbons. Additionally, the relationship between the carbon textural properties and the catalytic activity for CMD was also discussed.
基金the National Natural Science Foundation of China (No. 51574281), which supplied us with the facilities and funds needed to completed the experiments
文摘Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous reduction of zinc-bearing dusts and activation of low-rank coal was developed and its mechanism was clarified in this paper.Under the optimal conditions,the reduced zinc-bearing dusts containing low harmful elements(0.02%Zn,0.015%K and 0.03%Na)could be made as high-quality burden for blast furnace while the low-rank coal was transferred into K,Na-embedded activated carbon,which can be used as effective adsorbent for purification of SO_(2) and NO-containing flue gases.The solid wastes were successfully utilized to treat the flue gases through the process.The synergetic activation and reduction mechanism in the process was revealed.The coupling effect between reduction reactions of metal oxides in the dusts and activation reaction of carbon in the coal promoted the simultaneous reduction and activation process.In the meanwhile,part of the potassium and sodium from the zinc-bearing dusts could be adsorbed by the activated carbon and played a catalytic role in the activation process.
文摘A theoretical and experimental study was conducted to accurately determine the amount of adsorption and desorption of methane by various Granular Activated Carbon （GAC） under different physical conditions. To carry out the experiments, the volumetric method was used up to 500 psia at constant temperature of 25℃. In these experiments, adsorption as well as desorption capacities of four different GAC in the adsorption of methane, the major constituent of natural gas, at various equilibrium pressures and a constant temperature were studied. Also, various adsorption isotherm models were used to model the experimental data collected from the experiments. The accuracy of the results obtained from the adsorption isotherm models was compared and the values for the regressed parameters were reported. The results shows that the physical characteristics of activated carbons such as BET surface area, micropore volume, packing density, and pore size distribution play an important role in the amount of methane to be adsorbed and desorbed.
基金Projects 50672025 and 50730003 supported by the National Natural Science Foundation of China
文摘Nitrogen-containing carbons were prepared by modification of activated carbons.The modified carbons were used as electrode materials with improved electrochemical performance.Precursor anthracite was activated by KOH(KOH:anthracite= 1:1), modified by melamine or urea and then treated at 1173 K to obtain the modified carbons.The porous structure, the chemical composition and the electrochemical characteristics of the carbons were investigated by nitrogen sorption, XPS and electrochemical methods respectively.Electrochemical experiments were performed in an organic electrolytic solution of 1 M(C2H5)4NBF4/PC.The samples modified by the different methods showed differences in chemical composition that introduced varying degrees of electrochemical performance enhancement.The presence of nitrogen enhanced the electron donor properties and the surface wettability of the activated carbons:this ensured a sufficient utilization of the exposed surface for charge storage.
基金supported by National Natural Science Foundation of China(No.50876077)
文摘Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasmatreated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.
基金The authors thank the National Natural Science Foundation of China(No.51906130)the Natural Science Foundation of Shandong Province(No.ZR2019BEE053)+1 种基金the Key R&D and Development Plan of Shandong Province(2020CXGC011401)the Foundation of Shandong Key Lab of Energy Carbon Reduction and Resource Utilization,Shandong University(No.ECRRU201804)for the financial support.
文摘In this study,the Heishan coal was used to prepare a series of activated carbon(AC)samples via a vapor deposition method.The effects of the Fe(NO_(3))3/coal weight ratio on the physicochemical properties of the activated carbon were systematically investigated,and the AC samples were analyzed by the N2 adsorption-desorption technique,the scanning electron microscopy,the X-ray diffraction,the Raman spectroscopy,and the Fourier transform infrared spectroscopy.Furthermore,the adsorption properties of ethyl acetate were investigated.The results indicated that as the Fe(NO_(3))3/coal mass ratio increased from 1:8 to 1:2,the specific surface area,the total pore volume and the micropore volume initially increased and then decreased.The specific surface area increased from 560.86 m^(2)/g to 685.90 m^(2)/g,and then decreased to 299.56 m^(2)/g.The total pore volume and micropore volume increased from 0.29 cm^(3)/g and 0.17 cm^(3)/g to 0.30 cm^(3)/g and 0.22 cm^(3)/g,and then decreased to 0.16 cm^(3)/g and 0.10 cm^(3)/g,respectively.The optimized ratio was 1:8.During the activation process,iron ions infiltrated the activated carbon to promote the development of the pore structure,the pore size of which was between 2.5 nm and 3 nm in daimeter.This approach could enhance the capacity for adsorption of ethyl acetate.It is worth noting that the ACs displaying the largest specific surface area and total pore volume(685.90 m^(2)/g and 0.30 cm^(3)/g)were formed under the optimized activation conditions(950℃,20%(volume)of CO_(2),ratio 1:5),and the maximum AC capacity for adsorption of ethyl acetate was 962.62 mg/g.After seven repeated thermal regeneration experiments,the saturated AC adsorption capacity was still above 90%.
文摘Adsorption and desorption of methane by activated carbon （AC） at constant temperature and at various pressures were investigated. The effect of moisture was also studied. A volumetric method was used, up to 40 bar, at a temperature of 273.5 K. Results of a dry AC sample were compared with those obtained from a moist sample and two different ACs with different physical and surface properties were used. As expected, the results showed that the existence of moisture, trapped in the AC pores, could lead to a decrease in the amount of methane adsorbed and a decrease in the amount of methane delivered during desorption. To model the experimental results, a large variety of adsorption isotherms were used. The regressed parameters for the adsorption isotherms were obtained using the experimental data generated in the present study. The accuracy of the results obtained from the different adsorption isotherms was favorably compared.
基金This study was supported by the CNPC Research Institute of Safety and Environmental Protection Technology(No.PPCIP2017005).
文摘The hierarchical nanostructured N-doped TiO2 immobilized activated carbon fiber(N-TiO2/ACF)porous composites are fabricated to removal dynamic toluene gas.The results show that nitrogen ions doping and ACF modification can decrease the band gap of TiO2,leading to red shift toward visible light region.Interestingly,N-TiO2/ACF exhibits strongly synergistic effect owing to high surface area,good crystallinity,enhanced bandgap structure and light harvesting.The toluene removal rate of N-TiO2/ACF composites is 2.29 times higher than that of TiO2.The N-TiO2/ACF for toluene degradation followed the Langmuir-Hinshelwood kinetic model,and the rate constant is enhanced 8 times compared with TiO2.The possible photodegradation pathway and mechanisms are proposed.
