Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide w...Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^(-1),which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.展开更多
We prepared a kind of metal oxide-modified walnut-shell activated carbon(MWAC) by KOH chemical activation method and used for PH_3 adsorption removal. Meanwhile, the PH_3 adsorption equilibrium was investigated experi...We prepared a kind of metal oxide-modified walnut-shell activated carbon(MWAC) by KOH chemical activation method and used for PH_3 adsorption removal. Meanwhile, the PH_3 adsorption equilibrium was investigated experimentally and fitted by the Toth equation, and the isosteric heat of PH_3 adsorption was calculated by the Clausius-Clapeyron Equation. The exhausted MWAC was regenerated by water washing and air drying. Moreover, the properties of five different samples were characterized by N_2 adsorption isotherm, SEM/EDS, XPS, and FTIR. The results showed that the maximum PH_3 equilibrium adsorption capacity was 595.56 mg/g. The MWAC had an energetically heterogeneous surface due to values of isosteric heat of adsorption ranging from 43 to 90 kJ/mol. The regeneration method provided an effective way for both adsorption species recycling and exhausted carbon regeneration. The high removal efficiency and big equilibrium adsorption capacity for PH_3 adsorption on the MWAC were related to its large surface area and high oxidation activity in PH_3 adsorption-oxidation to H_3 PO_4 and P_2 O_5. Furthermore, a possible PH_3 adsorption mechanism was proposed.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
This paper focuses on the development of three types of activated carbon (AC) adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite (ENG). Their thermal...This paper focuses on the development of three types of activated carbon (AC) adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite (ENG). Their thermal conductivity was investigated with the steady-state heat source method and the permeability was tested with nitrogen as the gas source. Results show that the thermal conductivity of granular AC with different sizes al-most maintains a constant at 0.36 W·(m·K)-1, while the value modestly increases to 0.40 W·(m·K)-1 for the con-solidated AC with chemical binder. The consolidated AC with ENG at the density of 600 kg·m-3 shows the best heat transfer performance and their thermal conductivity vary from 2.08 W·(m·K)-1 to 2.61 W·(m·K)-1 according to its fraction of AC. However, the granular AC and consolidated AC with chemical binder show the better permeability performance than consolidated AC with ENG binder whose permeability changes from 6.98×10-13 m2 to 5.16×10-11 m2 and the maximum occurs when the content of AC reaches 71.4% (by mass). According to the different thermal properties, the refrigeration application of three types of adsorbents is analyzed.展开更多
In this study,two regeneration methods(dielectric barrier discharge(DBD)plasma and ozone(O3)regeneration)of saturated granular activated carbon(GAC)with pentachlorophenol(PCP)were compared.The results show that the tw...In this study,two regeneration methods(dielectric barrier discharge(DBD)plasma and ozone(O3)regeneration)of saturated granular activated carbon(GAC)with pentachlorophenol(PCP)were compared.The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent.Comparing the DBD plasma with O3regeneration,the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3regeneration.O3regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC,which causes a decrease in PCP on GAC uptake.With increasing regeneration cycles,the regeneration efficiencies of the two methods decrease,but the decrease in the regeneration efficiencies of GAC after O3regeneration is very obvious compared with that after DBD plasma regeneration.Furthermore,the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique,and all the adsorption equilibrium isotherms fit the Langmuir model fairly well,which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process,but to shift the equilibrium towards lower adsorption concentrations.Analyses of the weight loss of GAC show that O3regeneration has a lower weight loss than DBD plasma regeneration.展开更多
In this paper, a pulsed discharge plasma(PDP) system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7(AO7) exhausted granular activated carbon(GAC). Regenera...In this paper, a pulsed discharge plasma(PDP) system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7(AO7) exhausted granular activated carbon(GAC). Regeneration of GAC was studied under different conditions of peak pulse discharge voltage and water p H, as well as the modification effect of GAC by the pulse discharge process, to figure out the regeneration efficiency and the change of the GAC structure by the PDP treatment. The obtained results showed that there was an appropriate peak pulse voltage and an optimal initial p H value of the solution for GAC regeneration. Analyses of scanning electron microscope(SEM), Boehm titration, Brunauer-Emmett-Teller(BET), Horvath-Kawazoe(HK), and X-ray Diffraction(XRD) showed that there were more mesopore and macropore in the regenerated GAC and the structure turned smoother with the increase of discharge voltage;the amount of acidic functional groups on the GAC surface increased while the amount of basic functional groups decreased after the regeneration process. From the result of the XRD analysis,there were no new substances produced on the GAC after PDP treatment.展开更多
The powdered activated carbon which had adsorbed phenylglycine solution from pharmaceutics factory can be regenerated by mean of irradiation of high-energy electron beams in oxygen, nitrogen and water vapor respective...The powdered activated carbon which had adsorbed phenylglycine solution from pharmaceutics factory can be regenerated by mean of irradiation of high-energy electron beams in oxygen, nitrogen and water vapor respectively. The effects of radiation dose and beam current on regeneration of activated carbon in different atmosphere were studied. Differential scanning calorimetry (DSC) and the iodine number of activated carbon were used to monitor the change of carbon adsorption. The results show that the powder activated carbon polluted with phenlglycine could be regenerated effectively by irradiation of high energy electron beams in nitrogen stream. The generation did not need high temperature, and the weight loss of carbon and energy consumption were minimum.展开更多
A combined method of granular activated carbon(GAC) adsorption and bipolar pulse dielectric barrier discharge(DBD) plasma regeneration was employed to degrade phenol in water.After being saturated with phenol,the GAC ...A combined method of granular activated carbon(GAC) adsorption and bipolar pulse dielectric barrier discharge(DBD) plasma regeneration was employed to degrade phenol in water.After being saturated with phenol,the GAC was filled into the DBD reactor driven by bipolar pulse power for regeneration under various operating parameters.The results showed that different peak voltages,air flow rates,and GAC content can affect phenol decomposition and its major degradation intermediates,such as catechol,hydroquinone,and benzoquinone.The higher voltage and air support were conducive to the removal of phenol,and the proper water moisture of the GAC was 20%.The amount of H2 O2 on the GAC was quantitatively determined,and its laws of production were similar to phenol elimination.Under the optimized conditions,the elimination of phenol on the GAC was confirmed by Fourier transform infrared spectroscopy,and the total removal of organic carbons achieved 50.4%.Also,a possible degradation mechanism was proposed based on the HPLC analysis.Meanwhile,the regeneration efficiency of the GAC was improved with the discharge treatment time,which attained 88.5% after 100 min of DBD processing.展开更多
Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature > activated time > impreg...Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature > activated time > impregnation ratio > impregnation time. The optimum condition was found at an impregnation ratio of 2.5, an impregnation time of 9 hr, an activated temperature of 500°C, and an activated time of 80 min. The Brunauer-Emmett-Teller surface area and average pore size of the activated carbon were 1279 m2/g and 5.585 nm, respectively. A heterogeneous structure in terms of both size and shape was highly developed and widely distributed on the carbon surface. Some groups containing oxygen and phosphorus were formed, and the carboxyl group was the major oxygen-containing functional group. An isotherm equilibrium study was carried out to investigate the adsorption capacity of the activated carbon. The data fit the Langmuir isotherm equation, with maximum monolayer adsorption capacities of 192.30 mg/g for Neutral Red and 196.08 mg/g for Malachite Green. Dye-exhausted carbon could be regenerated effectively by thermal treatment. The results indicated that cattail-derived activated carbon was a promising adsorbent for the removal of cationic dyes from aqueous solutions.展开更多
Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were f...Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were further modified by potassium ferrate to finally prepare high-performance carbon for VOCs adsorption.At the same time,the samples before and after modification were systematically studied through characterization techniques such as SEM,Raman spectrometry,FT-IR,XPS,and dynamic/static adsorption.The results showed that the specific surface area and pore volume of the RAC after modification by the strong oxidant potassium ferrate increased by 1.4 times;the degree of defects was enhanced and the content of oxygen-containing functional groups on the surface increased significantly.Among them,the sample modified with potassium ferrate for 24 h had the best dynamic toluene adsorption performance(375.5 mg/g),and the dynamic adsorption capacity was twice that of the original sample(192.8 mg/g).The static adsorption test found that the maximum adsorption capacity of RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h was 796 mg/g,which indicated that the potassium ferrate modification treatment could significantly increase the VOCs adsorption performance of RAC.In addition,through consecutive toluene adsorption-desorption cycle tests,it was found that the RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h sample still retained 91%of adsorption activity after the fifth regeneration cycle.This indicates that RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h has good cycle stability and great application value for the efficient purification of industrial waste VOCs gas.展开更多
To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstru...To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.展开更多
Effluents containing inorganic contaminants are releasing into the environment untreated despite being hazardous to man and environment. It is costly and unsustainable to use conventional methods to remove them from d...Effluents containing inorganic contaminants are releasing into the environment untreated despite being hazardous to man and environment. It is costly and unsustainable to use conventional methods to remove them from dilute aqueous solution. Adsorption involving granular activated carbon is an alternative method for treating such effluents. Granular activated carbon is structurally strong, highly resistance to attrition and wearing, large and can easily separate from the effluents. However, its surface is highly hydrophobic and has little surface charge thereby reducing its adsorption capacity for anion or cation. This article reviews surfactant modification of activated carbon to enhance its adsorption capacity for inorganic contaminants and key factors affecting the adsorption efficiency. They include initial concentration of contaminants, contact time, solution pH, solution temperature, adsorbent concentration, ionic strength, competing ions, type of surfactant, and surfactant concentration. The modified activated carbon usually shows maximum contaminant uptake around its critical micelles concentration. Surfactant modification reduces specific surface area and/or micro pore volume but hot NaOH or HNO3 treatment before surfactant modification minimises this drawbacks and increases the net surface charge. Overall, surfactant modification is a simple but efficient method of enhancing adsorption capacity of activated carbon for removing anion or cation from aqueous solution. However, a handful publication is available on the regeneration of the spent (saturated) surfactant modified activated carbons. Hence, more research efforts should be directed towards proper regenerating reagents and the optimise conditions such as contact time, concentration, and temperature for regenerating spent modified activated carbons.展开更多
The study of the performances of regenerated activated carbons for the adsorption of MO(methyl orange)in an aqueous medium was carried out with the aim to evaluate the adsorption capacities of these activated carbons....The study of the performances of regenerated activated carbons for the adsorption of MO(methyl orange)in an aqueous medium was carried out with the aim to evaluate the adsorption capacities of these activated carbons.Three regenerated activated carbons issued from the unit of oil treatment of the thermal power station of Dibamba(Cameroon)-DPDC(Dibamba Power Development Company)were obtained thermally and chemically.These three samples(namely CAR 400℃(chemical regenerated activated carbon at 400℃),CAR 700℃(physical regenerated activated carbon at 700℃)and CAR 900℃(physical regenerated activated carbon at 900℃))and the non-used one CA were characterized by iodine number,XRD(X-ray Diffraction)and FTIR(Fourier-transform infrared spectroscopy).MO adsorption tests were performed in batch mode;this technique allowed the study of the influence of the parameters such as:the contact time,the initial’s MO concentration and the pH.Moreover,different kinetic models(first-order,pseudo-second-order and Webber and Morris intra-particle diffusion)and adsorption isotherms(Langmuir and Freundlich)are used for the evaluation of adsorption capacities.The physicochemical characterization of these adsorbents showed that they were micro-porous(iodine value:600 mg/g)and strongly crystallized according to their regeneration pathways.The influence of the parameters revealed that the adsorption of MO is the most favorable for concentrations from 5 to 25 mg/L(for materials CA and CAR 400℃)and 10 to 25 g/L(for materials CAR 700℃ and 900℃);and that it was maximum in acid medium(at pH=3 on the materials CA,CAR 400℃,CAR 900℃ and at pH=5 on the material CAR 900℃).The modeling of the adsorption kinetics of MO has revealed the conformity of the kinetic model of pseudosecond-order and intra-particle diffusion for some of these materials.The study of isotherms has shown that the Langmuir isotherm best describes the adsorption of MO on most of these adsorbents.展开更多
The presence of oxygen functional groups is detrimental to the capacitive performance of porous carbon electrode in organic electrolyte. In this regards, hydrogen thermal reduction has been demonstrated effective appr...The presence of oxygen functional groups is detrimental to the capacitive performance of porous carbon electrode in organic electrolyte. In this regards, hydrogen thermal reduction has been demonstrated effective approach in removing the unstable surface oxygen while maintaining the high porosity of carbon matrix. However, the exact evolution mechanism of various oxygen species during this process, as well as the correlation with electrochemical properties, is still under development. Herein, biomass-based porous carbon is adopted as the model material to trace its structure evolution of oxygen removal under hydrogen thermal reduction process with the temperature range of 400–800 °C. The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700°C. XPS, TPRMS and Boehm titration results indicate that the oxygen elimination undergoes three distinctive stages(intermolecular dehydration, hydrogenation and decomposition reactions). The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700 °C. Benefiting from the stable electrochemical interface and the optimized porous structure, the as-obtained HAC-700 exhibit significantly suppressed self-discharge and leak current, with improved cycling stability, which is attributable to the stabilization of electrochemical interface between carbon surface and electrolyte. The result provides insights for rational design of surface chemistry for high-performance carbon electrode towards advanced energy storage.展开更多
基金Funded by the National High Technology Research and Development Program of China("863"Program)(No.2006AA06A310)
文摘Using a walnut shellas a carbon source and ZnCl_2 as an activating agent,we resolved the temperature gradient problems of activated carbon in the microwave desorption process.An appropriate amount of silicon carbide was added to prepare the composite activated carbon with high thermalconductivity while developing VOC adsorption-microwave regeneration technology.The experimentalresults show that the coefficient of thermalconductivity of SiC-AC is three times as much as those of AC and SY-6.When microwave power was 480 W in its microwave desorption,the temperature of the bed thermaldesorption was 10 ℃ to 30 ℃ below that of normalactivated carbon prepared in our laboratory.The toluene desorption activation energy was 16.05 k J·mol^(-1),which was 15% less than the desorption activation energy of commercialactivated carbon.This study testified that the process could maintain its high adsorption and regeneration desorption performances.
基金Funded by the National Natural Science Foundation of China(51566017)
文摘We prepared a kind of metal oxide-modified walnut-shell activated carbon(MWAC) by KOH chemical activation method and used for PH_3 adsorption removal. Meanwhile, the PH_3 adsorption equilibrium was investigated experimentally and fitted by the Toth equation, and the isosteric heat of PH_3 adsorption was calculated by the Clausius-Clapeyron Equation. The exhausted MWAC was regenerated by water washing and air drying. Moreover, the properties of five different samples were characterized by N_2 adsorption isotherm, SEM/EDS, XPS, and FTIR. The results showed that the maximum PH_3 equilibrium adsorption capacity was 595.56 mg/g. The MWAC had an energetically heterogeneous surface due to values of isosteric heat of adsorption ranging from 43 to 90 kJ/mol. The regeneration method provided an effective way for both adsorption species recycling and exhausted carbon regeneration. The high removal efficiency and big equilibrium adsorption capacity for PH_3 adsorption on the MWAC were related to its large surface area and high oxidation activity in PH_3 adsorption-oxidation to H_3 PO_4 and P_2 O_5. Furthermore, a possible PH_3 adsorption mechanism was proposed.
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%.
基金Supported by the National Science Foundation for Excellent Young Scholars （51222601）, the International Collaborating Project Funded by the Foundation of Science and Technology Commission of Shanghai Municipality （11160706000）, the Program for New Century Excellent Talents in University by the Ministry of Education of China and the Shanghai Pujiang Program of China.
文摘This paper focuses on the development of three types of activated carbon (AC) adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite (ENG). Their thermal conductivity was investigated with the steady-state heat source method and the permeability was tested with nitrogen as the gas source. Results show that the thermal conductivity of granular AC with different sizes al-most maintains a constant at 0.36 W·(m·K)-1, while the value modestly increases to 0.40 W·(m·K)-1 for the con-solidated AC with chemical binder. The consolidated AC with ENG at the density of 600 kg·m-3 shows the best heat transfer performance and their thermal conductivity vary from 2.08 W·(m·K)-1 to 2.61 W·(m·K)-1 according to its fraction of AC. However, the granular AC and consolidated AC with chemical binder show the better permeability performance than consolidated AC with ENG binder whose permeability changes from 6.98×10-13 m2 to 5.16×10-11 m2 and the maximum occurs when the content of AC reaches 71.4% (by mass). According to the different thermal properties, the refrigeration application of three types of adsorbents is analyzed.
基金supported by National Natural Science Foundation of China(No.21107085)National High Technology Research and Development Program of China(No.2008AA06Z308)
文摘In this study,two regeneration methods(dielectric barrier discharge(DBD)plasma and ozone(O3)regeneration)of saturated granular activated carbon(GAC)with pentachlorophenol(PCP)were compared.The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent.Comparing the DBD plasma with O3regeneration,the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3regeneration.O3regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC,which causes a decrease in PCP on GAC uptake.With increasing regeneration cycles,the regeneration efficiencies of the two methods decrease,but the decrease in the regeneration efficiencies of GAC after O3regeneration is very obvious compared with that after DBD plasma regeneration.Furthermore,the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique,and all the adsorption equilibrium isotherms fit the Langmuir model fairly well,which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process,but to shift the equilibrium towards lower adsorption concentrations.Analyses of the weight loss of GAC show that O3regeneration has a lower weight loss than DBD plasma regeneration.
基金financially supported by the National Natural Science Foundation of Zhejiang Province,China(No.Z505060)China Postdoctoral Science Foundation(No.2005038290).
基金supported by National Natural Science Foundation of China(No.21207052)China Postdoctoral Science Foundation(No.20110491353)Jiangsu Planned Projects for Postdoctoral Research Funds,China(No.1102116C)
文摘In this paper, a pulsed discharge plasma(PDP) system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7(AO7) exhausted granular activated carbon(GAC). Regeneration of GAC was studied under different conditions of peak pulse discharge voltage and water p H, as well as the modification effect of GAC by the pulse discharge process, to figure out the regeneration efficiency and the change of the GAC structure by the PDP treatment. The obtained results showed that there was an appropriate peak pulse voltage and an optimal initial p H value of the solution for GAC regeneration. Analyses of scanning electron microscope(SEM), Boehm titration, Brunauer-Emmett-Teller(BET), Horvath-Kawazoe(HK), and X-ray Diffraction(XRD) showed that there were more mesopore and macropore in the regenerated GAC and the structure turned smoother with the increase of discharge voltage;the amount of acidic functional groups on the GAC surface increased while the amount of basic functional groups decreased after the regeneration process. From the result of the XRD analysis,there were no new substances produced on the GAC after PDP treatment.
基金the Science Foundation of Shanghai Municipal of Commission of Education (99A44) and a Bilateral Scientific Project between C
文摘The powdered activated carbon which had adsorbed phenylglycine solution from pharmaceutics factory can be regenerated by mean of irradiation of high-energy electron beams in oxygen, nitrogen and water vapor respectively. The effects of radiation dose and beam current on regeneration of activated carbon in different atmosphere were studied. Differential scanning calorimetry (DSC) and the iodine number of activated carbon were used to monitor the change of carbon adsorption. The results show that the powder activated carbon polluted with phenlglycine could be regenerated effectively by irradiation of high energy electron beams in nitrogen stream. The generation did not need high temperature, and the weight loss of carbon and energy consumption were minimum.
基金financially supported by National Natural Science Foundation of China(Project No.51608468)the Natural Science Foundation of Hebei Province(Project Nos.B2015203303 and B2015203300)+3 种基金the China Postdoctoral Science Foundation(Project Nos.2015M580216 and 2016M601285)the Youth Teacher Independent Research Program of Yanshan University(Project No.15LGA013)the Hebei Province Preferred Postdoctoral Science Foundation(B2016003019)the Open Foundation of Key Laboratory of Industrial Ecology and Environmental Engineering(MOE)
文摘A combined method of granular activated carbon(GAC) adsorption and bipolar pulse dielectric barrier discharge(DBD) plasma regeneration was employed to degrade phenol in water.After being saturated with phenol,the GAC was filled into the DBD reactor driven by bipolar pulse power for regeneration under various operating parameters.The results showed that different peak voltages,air flow rates,and GAC content can affect phenol decomposition and its major degradation intermediates,such as catechol,hydroquinone,and benzoquinone.The higher voltage and air support were conducive to the removal of phenol,and the proper water moisture of the GAC was 20%.The amount of H2 O2 on the GAC was quantitatively determined,and its laws of production were similar to phenol elimination.Under the optimized conditions,the elimination of phenol on the GAC was confirmed by Fourier transform infrared spectroscopy,and the total removal of organic carbons achieved 50.4%.Also,a possible degradation mechanism was proposed based on the HPLC analysis.Meanwhile,the regeneration efficiency of the GAC was improved with the discharge treatment time,which attained 88.5% after 100 min of DBD processing.
基金supported by the National Key Technology R&D Program for the 11th Five-year Plan of China (No.2006BAC10B03)the National Natural Science Foundation of China-Japan Science and Technology Agency (NSFC-JST) Strategic Joint Research Project (No.50721140017)the National Natural Science Foundation of China (No.50508019)
文摘Activated carbon was prepared from cattail by H3PO4 activation. The effects influencing the surface area of the resulting activated carbon followed the sequence of activated temperature > activated time > impregnation ratio > impregnation time. The optimum condition was found at an impregnation ratio of 2.5, an impregnation time of 9 hr, an activated temperature of 500°C, and an activated time of 80 min. The Brunauer-Emmett-Teller surface area and average pore size of the activated carbon were 1279 m2/g and 5.585 nm, respectively. A heterogeneous structure in terms of both size and shape was highly developed and widely distributed on the carbon surface. Some groups containing oxygen and phosphorus were formed, and the carboxyl group was the major oxygen-containing functional group. An isotherm equilibrium study was carried out to investigate the adsorption capacity of the activated carbon. The data fit the Langmuir isotherm equation, with maximum monolayer adsorption capacities of 192.30 mg/g for Neutral Red and 196.08 mg/g for Malachite Green. Dye-exhausted carbon could be regenerated effectively by thermal treatment. The results indicated that cattail-derived activated carbon was a promising adsorbent for the removal of cationic dyes from aqueous solutions.
基金financialy supported by the National Natural Science Foundation of China (No.21936005,52070114,21876093)the Postdoctoral Science Program of China (No.2019M660061)
文摘Regenerated activated carbon(RAC)samples were prepared by carbon activation using waste activated carbon from solid waste resources as the carbon source precursor coupled with adding alkaline additives,and then were further modified by potassium ferrate to finally prepare high-performance carbon for VOCs adsorption.At the same time,the samples before and after modification were systematically studied through characterization techniques such as SEM,Raman spectrometry,FT-IR,XPS,and dynamic/static adsorption.The results showed that the specific surface area and pore volume of the RAC after modification by the strong oxidant potassium ferrate increased by 1.4 times;the degree of defects was enhanced and the content of oxygen-containing functional groups on the surface increased significantly.Among them,the sample modified with potassium ferrate for 24 h had the best dynamic toluene adsorption performance(375.5 mg/g),and the dynamic adsorption capacity was twice that of the original sample(192.8 mg/g).The static adsorption test found that the maximum adsorption capacity of RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h was 796 mg/g,which indicated that the potassium ferrate modification treatment could significantly increase the VOCs adsorption performance of RAC.In addition,through consecutive toluene adsorption-desorption cycle tests,it was found that the RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h sample still retained 91%of adsorption activity after the fifth regeneration cycle.This indicates that RAC-6%K_(2)FeO_(4)+H_(2)SO_(4)-24h has good cycle stability and great application value for the efficient purification of industrial waste VOCs gas.
基金Open Fund of Key Laboratory of Ministry of Education for Metallurgical Emission Reduction and Comprehensive Utilization of Resources,China(No.JKF19-08)General Project of Science and Technology Plan of Yunnan Science and Technology Department,China(No.2019FB077)+1 种基金Industrialization Cultivation Project of Scientific Research Fund of Yunnan Provincial Department of Education,China(No.2016CYH07)Top Young Talents of Yunnan Ten Thousand Talents Plan,China(No.YNWR-QNBJ-2019-263)。
文摘To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.
文摘Effluents containing inorganic contaminants are releasing into the environment untreated despite being hazardous to man and environment. It is costly and unsustainable to use conventional methods to remove them from dilute aqueous solution. Adsorption involving granular activated carbon is an alternative method for treating such effluents. Granular activated carbon is structurally strong, highly resistance to attrition and wearing, large and can easily separate from the effluents. However, its surface is highly hydrophobic and has little surface charge thereby reducing its adsorption capacity for anion or cation. This article reviews surfactant modification of activated carbon to enhance its adsorption capacity for inorganic contaminants and key factors affecting the adsorption efficiency. They include initial concentration of contaminants, contact time, solution pH, solution temperature, adsorbent concentration, ionic strength, competing ions, type of surfactant, and surfactant concentration. The modified activated carbon usually shows maximum contaminant uptake around its critical micelles concentration. Surfactant modification reduces specific surface area and/or micro pore volume but hot NaOH or HNO3 treatment before surfactant modification minimises this drawbacks and increases the net surface charge. Overall, surfactant modification is a simple but efficient method of enhancing adsorption capacity of activated carbon for removing anion or cation from aqueous solution. However, a handful publication is available on the regeneration of the spent (saturated) surfactant modified activated carbons. Hence, more research efforts should be directed towards proper regenerating reagents and the optimise conditions such as contact time, concentration, and temperature for regenerating spent modified activated carbons.
文摘The study of the performances of regenerated activated carbons for the adsorption of MO(methyl orange)in an aqueous medium was carried out with the aim to evaluate the adsorption capacities of these activated carbons.Three regenerated activated carbons issued from the unit of oil treatment of the thermal power station of Dibamba(Cameroon)-DPDC(Dibamba Power Development Company)were obtained thermally and chemically.These three samples(namely CAR 400℃(chemical regenerated activated carbon at 400℃),CAR 700℃(physical regenerated activated carbon at 700℃)and CAR 900℃(physical regenerated activated carbon at 900℃))and the non-used one CA were characterized by iodine number,XRD(X-ray Diffraction)and FTIR(Fourier-transform infrared spectroscopy).MO adsorption tests were performed in batch mode;this technique allowed the study of the influence of the parameters such as:the contact time,the initial’s MO concentration and the pH.Moreover,different kinetic models(first-order,pseudo-second-order and Webber and Morris intra-particle diffusion)and adsorption isotherms(Langmuir and Freundlich)are used for the evaluation of adsorption capacities.The physicochemical characterization of these adsorbents showed that they were micro-porous(iodine value:600 mg/g)and strongly crystallized according to their regeneration pathways.The influence of the parameters revealed that the adsorption of MO is the most favorable for concentrations from 5 to 25 mg/L(for materials CA and CAR 400℃)and 10 to 25 g/L(for materials CAR 700℃ and 900℃);and that it was maximum in acid medium(at pH=3 on the materials CA,CAR 400℃,CAR 900℃ and at pH=5 on the material CAR 900℃).The modeling of the adsorption kinetics of MO has revealed the conformity of the kinetic model of pseudosecond-order and intra-particle diffusion for some of these materials.The study of isotherms has shown that the Langmuir isotherm best describes the adsorption of MO on most of these adsorbents.
基金National Science Foundation for Excellent Young Scholars of China (21922815)Key Research and Development (R&D) Projects of Shanxi Province (201903D121007)+3 种基金Natural Science Foundations of Shanxi Province (201801D221156)DNL Cooperation Fund of CAS (DNL180308)Science and Technology Service Network Initiative of CAS (KFJ-STS-ZDTP-068)Youth Innovation Promotion Association of CAS。
文摘The presence of oxygen functional groups is detrimental to the capacitive performance of porous carbon electrode in organic electrolyte. In this regards, hydrogen thermal reduction has been demonstrated effective approach in removing the unstable surface oxygen while maintaining the high porosity of carbon matrix. However, the exact evolution mechanism of various oxygen species during this process, as well as the correlation with electrochemical properties, is still under development. Herein, biomass-based porous carbon is adopted as the model material to trace its structure evolution of oxygen removal under hydrogen thermal reduction process with the temperature range of 400–800 °C. The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700°C. XPS, TPRMS and Boehm titration results indicate that the oxygen elimination undergoes three distinctive stages(intermolecular dehydration, hydrogenation and decomposition reactions). The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700 °C. Benefiting from the stable electrochemical interface and the optimized porous structure, the as-obtained HAC-700 exhibit significantly suppressed self-discharge and leak current, with improved cycling stability, which is attributable to the stabilization of electrochemical interface between carbon surface and electrolyte. The result provides insights for rational design of surface chemistry for high-performance carbon electrode towards advanced energy storage.
