In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated c...In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon （SAC） supported photocatalyst doped with upconversion luminescence agent Er3＋：YAlO3 was prepared by immobilizing Er3＋：YAlO3/TiO2, which was obtained by combination of Er3＋：YAlO3 and TiO2 using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction （XRD）, energy dispersive X-ray spectra （EDS） analysis, scanning electron microscopy （SEM） and fluorescence spectra analysis （FSA）. The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange （MO） in aqueous solution under visible light irradiation from a LED lamp （λ400 nm）. The results showed that Er3＋：YAlO3 could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er3＋：YAlO3/TiO2 calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min-1 under visible light irradiation.展开更多
TiO2-coated activated carbon surface （TAs） composites were prepared by a sol-gel method with supercritical pretreatment. The photocatalytic degradation of acid yellow （AY） was investigated under UV radiation to es...TiO2-coated activated carbon surface （TAs） composites were prepared by a sol-gel method with supercritical pretreatment. The photocatalytic degradation of acid yellow （AY） was investigated under UV radiation to estimate activity of catalysts and determine the kinetics. And the effects of parameters including the initial concentration of AY, light intensity and TiO2 content in catalysts were examined. The results indicate that TAs has a higher efficiency in decomposition of AY than P25, pure TiO2 particles as well as the mixture of TiO2 powder and active carbon. The photocatalytic degradation rate is found to follow the pseudo-first order kinetics with respect to the AY concentration. The new kinetic model fairly resembles the classic Langmuir-Hinshelwood equation, and the rate constant is proportional to the square root of the light intensity in a wide range. However, its absorption performance depends on the surface areas of catalysts. The model fits quite well with the experimental data and elucidates phenomena about the effects of the TiO2 content in TAs on the degradation rate.展开更多
The technology for green and macro-conversion of solid waste biomass to prepare high-quality activated carbon demands urgent development.This study proposes a technique for synthesizing carbon adsorbents using trace K...The technology for green and macro-conversion of solid waste biomass to prepare high-quality activated carbon demands urgent development.This study proposes a technique for synthesizing carbon adsorbents using trace KOH-catalyzed CO_(2) activation.Comprehensive investigations were conducted on three aspects:physicochemical structure evolution of biochar,mechanistic understanding of trace KOH-facilitated CO_(2) activation processes,and application characteristics for CO_(2) adsorption.Results demonstrate that biochar activated by trace KOH(<10%)and CO_(2) achieves comparable specific surface area(1244.09 m^(2)/g)to that obtained with 100%KOH activation(1425.10 m^(2)/g).The pore structure characteristics(specific surface area and pore volume)are governed by CO and CH4 generated through K-salt catalyzed reactions between CO_(2) and biochar.The optimal CO_(2) adsorption capacities of KBC adsorbent reached 4.70 mmol/g(0℃)and 7.25 mmol/g(25℃),representing the maximum values among comparable carbon adsorbents.The 5%KBC-CO_(2) sample exhibited CO_(2) adsorption capacities of 3.19 and 5.01 mmol/g under respective conditions,attaining current average performance levels.Notably,CO_(2)/N_(2) selectivity(85∶15,volume ratio)reached 64.71 at 0.02 bar with robust cycling stability.Molecular dynamics simulations revealed that oxygen-containing functional groups accelerate CO_(2) adsorption kinetics and enhance micropore storage capacity.This technical route offers simplicity,environmental compatibility,and scalability,providing critical references for large-scale preparation of high-quality carbon materials.展开更多
The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts...The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts,while its symmetric charge distribution nature is not favorable for electron transfer and then hindering the efficient CO_(2)RR.Herein,we constructed a Ni SA/CNs single-atom catalyst.Notably,it features unique Ni-N_(4)-O active sites,featuring one axial O atom and four planar N atoms,constituting a broken symmetrical electronic structure of Ni-N_(4) sites.Furthermore,hierarchical pore structures were obtained with the assistance of NaNO_(3) pore-forming agent during thermal treatment process,which promote electronic and mass transfer.And the resulting high specific surface area can host more Ni-N_(4)-O active sites.These specialized active sites promote the key intermediate(∗CO)adsorption/desorption and suppresses hydrogen evolution.Consequently,the Ni SA/CNs catalyst exhibits a high turnover frequency(TOF)value,reaching 34,081 h^(-1) at-0.98 V vs.RHE.Additionally,it achieves an excellent CO Faradaic efficiency,exceeding 90%,over a wide potential range from-0.4 V to-1.0 V vs.RHE.This work not only offers a new method for the rational synthesize single-atom catalysts with unique Ni-N_(4)-O active sites,but also provides in-depth insight into the origin of catalytic activity of porous carbon-base catalysts.展开更多
A new nanostructured amino-functionalized magnetic bacterial cellulose/activated carbon（BC/AC）composite bioadsorbent（AMBCAC）was prepared for removal of Pb^2＋ and methyl orange（MO）from aqueous solution.The resul...A new nanostructured amino-functionalized magnetic bacterial cellulose/activated carbon（BC/AC）composite bioadsorbent（AMBCAC）was prepared for removal of Pb^2＋ and methyl orange（MO）from aqueous solution.The results demonstrated that the equilibrium adsorption capacity（qe）for Pb^2＋ obviously increases by 2.14 times after introduction of amino groups,the optimum p H for Pb^2＋and MO adsorption was 5.0 and 3.0,respectively,and the qeof AMBCAC was 161.78 mg g^-1 for Pb^2＋ and 83.26 mg g^-1 for MO under the optimal conditions in this investigation.The kinetics and adsorption isotherm data of the sorption process were well fitted by pseudo-second-order kinetic model and Langmuir isotherm respectively.The thermodynamic results（the Gibbs free energy change G〈0,the enthalpy change H〉0,the entropy change S〉0）implied that the adsorption process of Pb^2＋ and MO was feasible,endothermic and spontaneous in nature.These results support that the AMBCAC composite developed in this work can provide a cheap and efficient way for easy removal of both Pb^2＋ and MO as a promising adsorbent candidate for wastewater treatment.展开更多
The photocatalytic degradation of Rhodamine B(RhB)was carried out using TiO_(2)supported on activated carbon(TiO_(2)-AC)under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray...The photocatalytic degradation of Rhodamine B(RhB)was carried out using TiO_(2)supported on activated carbon(TiO_(2)-AC)under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction(XRD),transmission electron microscopy(TEM)and Brunauer-Emmett-Teller(BET).In the process of microwave-enhanced photocatalysis(MPC),RhB(30 mg/L)was almost completely decoloured in 10 min,and the mineralization efficiency was 96.0%in 20 min.The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25.Additionally,according to gas chromatography/mass spectrometry(GC/MS)and liquid chromatography/mass spectrometry(LC/MS)identification,the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates(N,N-diethyl-N'-ethyl-rhodamine(DER)),oxalic acid,malonic acid,snccinic acid,and phthalic acid,maleic acid,3-nitrobenzoic acid,and so on.The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure,and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide.展开更多
The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluate...The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments of Escherichia coli.The key factors affecting the inactivation effciency were investigated,including electric power of lamp, temperature,and pH values.The results show that the TiO2/AC composites have high inactivation properties of E.coli in compari...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 ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its...The ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its performance for the uptake of arsenate and arsenite species from aqueous solutions was investigated by batch experiments.Various techniques,including FESEM-EDX,p-XRD,XPS and BET surface area analysis,were employed to characterize the properties of the adsorbent and the arsenic adsorption mechanisms.The results showed thatδ-MnO2 covered on the surface and padded in the pores of the activated carbon.Adsorption kinetic studies revealed that approximately 90.1%and 76.8%of As(Ⅲ)and As(V),respectively,were removed by the adsorbent in the first 9 hr,and adsorption achieved equilibrium within 48 hr.The maximum adsorption capacities of As(V)and As(Ⅲ)at pH 4.0 calculated from Langmuir adsorption isotherms were 13.30 and 12.56 mg/g,respectively.The effect of pH on As(Ⅴ)and As(Ⅲ)removal was similar,and the removal efficiency significantly reduced with the increase of solution pH.Arsenite oxidation and adsorption kinetics showed that the As(Ⅴ)concentration in solution due to As(Ⅲ)oxidation and reductive dissolution of MnO2 increased rapidly during the first 12 min,and then gradually decreased.Based on the XPS analysis,nearly 93.3%of As(Ⅲ)had been oxidized to As(V)on the adsorbent surface and around 38.9%of Mn(Ⅳ)had been reduced to Mn(Ⅱ)after As(Ⅲ)adsorption.This approach provides a possible method for the purification of arsenic-contaminated groundwater.展开更多
Preparation of activated carbon from chicken waste is a promising way to produce a useful adsorbent for Hg removal. A three-stage activation process （drying at 200℃, pyrolysis in N2 atmosphere, followed by CO2 activ...Preparation of activated carbon from chicken waste is a promising way to produce a useful adsorbent for Hg removal. A three-stage activation process （drying at 200℃, pyrolysis in N2 atmosphere, followed by CO2 activation） was used for the production of activated samples. The effects of carbonization temperature （409-4500℃）, activation temperature （700-900℃）, and activation time （1-2.5 h） on the physicochemical properties （weight-loss and BET surface） of the prepared carbon wereinvestigated. Adsorptive removal of mercury from real flue gas onto activated carbon has been studied. The activated carbon from chicken waste has the same mercury capacity as commercial activated carbon （Darco LH） （Hg^v： 38.7% vs. 53.5%, Hg^0： 50.5% vs. 68.8%）, although its surface area is around 10 times smaller, 89.5 m^2/g vs. 862 m^2/g. The low cost activated carbon can be produced from chicken waste, and the procedure is suitable.展开更多
Activated carbon obtained from Astragalus residue was chemically activated by KOH and modified with KMnO4.The samples were characterized by N2 adsorption,Fourier transform infrared spectroscopy,X-ray diffractometry,sc...Activated carbon obtained from Astragalus residue was chemically activated by KOH and modified with KMnO4.The samples were characterized by N2 adsorption,Fourier transform infrared spectroscopy,X-ray diffractometry,scanning electron microscopy,and Boehm titration.Accordingly,the original and modified carbon materials were used for the removal of Cd2+from aqueous solution by batch adsorption experiments.Results showed that the contents of oxygen-containing functional groups increased,and MnO2 was nearly uniformly deposited on the surface of activated carbon after modification by KMnO4.The adsorption kinetics was described by pseudo-second order model.Langmuir model fitted the adsorption-isotherm experimental data of Cd2+better than the Freundlich model.The maximum adsorption capacities of the activated carbon before and after modification for Cd2+were 116.96 and 217.00 mg/g,respectively.KMnO4 considerably changed the physicochemical properties and surface texture of activated carbon and enhanced the adsorption capacity of activated carbon for Cd2+.展开更多
TiO2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO2 particles can be ...TiO2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO2 particles can be effectively suppressed by added polyethylene glycol （PEG） as a surface modifier. The average particle diameter of TiO2, specific surface area and absorbability of catalyst can be modified. Based on characteristics of the TiO2 photocatalyst with XRD, specific surface area, adsorption valves of methylene blue and the amount of TiO2 supported on the activated carbon, the photocatalytic degradation of L-acid was studied. The effect of the factors, such as pH of the solution, the initial concentration of L-acid on the photocatalytic degradation of L-acid, were studied also. It was found that when the pH of the solution is 1.95, the amount of photocatalyst is 0.5 g, the concentration of the L-acid solution is 1.34×10^3 mol/L and the illumination time is 7 h, the photocatalytic degradation efficiency of L-acid can reach 89,88%, The catalyst was reused 6 times and its degradation efficiency hardly changed.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
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
A series of oxidants supported on coconut shell-based activated carbon(CAC) through microwave irradiation were prepared and characterized using scanning electron microscopy(SEM), N_2 adsorption/desorption analysis, an...A series of oxidants supported on coconut shell-based activated carbon(CAC) through microwave irradiation were prepared and characterized using scanning electron microscopy(SEM), N_2 adsorption/desorption analysis, and X-ray photoelectron spectroscopy(XPS). The SO_2 adsorption capacities and rates were evaluated by adsorption tests performed in a fixed bed reactor with a simulated flue gas, and the adsorption isotherm models were validated against the experimental results. The findings revealed that the SO_2 adsorption capacity decreased in the following order: MW-K_2Cr_2O_7-CAC > MWKMnO_4-CAC > MW-H_2O_2-CAC > MW-CAC. The SO_2 adsorption capacities and adsorption rates of the samples increased with an increasing oxidizability of the oxidants owing to the increment of mean pore size and oxygen-containing functional groups. In addition, a high initial SO_2 concentration and a low bed temperature could positively affect the SO2 adsorption. Finally, the Langmuir model validated that SO_2 was mainly adsorbed through chemical adsorption on the sample surfaces.展开更多
Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce d...Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce dehydration and/or aromatization to change the structure of cellulose/hemicellulose.This might interfere with evolution of structures of AC,which was investigated herein via thermal pretreatment of willow branch(WB)from 200 to 360℃and the subsequent activation with ZnCl_(2) at 550℃.The results showed that thermal pretreatment at 360℃(WB-360)could lead to substantial pyrolysis to form biochar,with a yield of 31.9%,accompanying with nearly complete destruction of cellulose crystals and remarkably enhanced aromatic degree.However,cellulose residual in WB-360 could still be activated to form AC-360 with specific surface area of 1837.9 m~2·g^(-1),which was lower than that in AC from activation of untreated WB(AC-blank,2077.8 m~2·g^(-1)).Nonetheless,the AC-200 from activation of WB-200 had more developed pores(2113.9 m~2·g^(-1))and superior capability for adsorption of phenol,due to increased permeability of ZnCl_(2) to the largely intact cellulose structure in WB-200.The thermal pretreatment did increase diameters of micropores of AC but reduced the overall yield of AC(26.8%for AC-blank versus 18.0%for AC-360),resulting from accelerated cracking but reduced intensity of condensation.In-situ infrared characterization of the activation showed that ZnCl_(2) mainly catalyzed dehydration,dehydrogenation,condensation,and aromatization but not cracking,suppressing the formation of derivatives of cellulose and lignin in bio-oil.The thermal pretreatment formed phenolic-OH and C=O with higher chemical innerness,which changed the reaction network in activation,shifting morphology of fibrous structures in AC-blank to“melting surface”in AC-200 or AC-280.展开更多
An activated carbon pore-expanding technique was achieved through innovative reactivation by CO_2/microwave.The original and modified activated carbons were characterized by nitrogen adsorption–desorption,scanning el...An activated carbon pore-expanding technique was achieved through innovative reactivation by CO_2/microwave.The original and modified activated carbons were characterized by nitrogen adsorption–desorption,scanning electron microscopy,transmission electron microcopy,and Fourier transform infrared spectroscopy.The mesopore volume increased from 0.122 cm^3·g^(-1) to 0.270 cm^3·g^(-1),and a hierarchical pore structure was formed.A gradual decrease in the phenolic hydroxyl and carboxyl groups on the surface of activated carbon enhanced the surface inertia of granular activated carbon(GAC).The toluene desorption rate of the modified sample increased by 8.81% compared with that of the original GAC.Adsorption isotherm fittings revealed that the Langmuir model was applicable for the original and modified activated carbons.The isosteric adsorption heat of toluene on the activated carbon decreased by approximately 50%,which endowed the modified sample with excellent stability in application.The modified samples showed an enhanced desorption performance of toluene,thereby opening a way to extend the cycle life and improve the economic performance of carbon adsorbent in practical engineering applications.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
The role of Nil（NO3）2 in the preparation of a magnetic activated carbon is reported in this paper. Magnetic coal-based activated carbons （MCAC） were prepared from Taixi anthracite with low ash content in the prese...The role of Nil（NO3）2 in the preparation of a magnetic activated carbon is reported in this paper. Magnetic coal-based activated carbons （MCAC） were prepared from Taixi anthracite with low ash content in the presence of Ni（NO3）2. The MCAC materials were characterized by a vibrating sample magnetometer （VSM）, X-ray diffraction （XRD）, a scanning electric microscope （SEM）, and by N2 adsorption. The cylindri- cal precursors and derived char were also subjected to thermogravimetric analysis to compare their behavior of weight losses during carbonization. The results show that MCAC has a larger surface area （1074 m21g） and a higher pore volume （0.5792 cm3/g） with enhanced mesopore ratio （by about 10~）. It also has a high saturation magnetization （1.6749 emu/g） and low coercivity （43.26 Oe）, which allows the material to be magnetically separated. The MCAC is easily magnetized because the nickel salt is con- vetted into Ni during carbonization and activation. Metallic Ni has a strong magnetism on account of electrostatic interaction. Added Ni（NO3）2 catalyzes the carbonization and activation process by accelerat- ing burn off of the carbon, which contributes to the development of mesopores and macropores in the activated carbon.展开更多
基金Projects (50908096, 50908097) supported by the National Natural Science Foundation of ChinaProject (20100471251) supported by China Postdoctoral Science Foundation
文摘In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon （SAC） supported photocatalyst doped with upconversion luminescence agent Er3＋：YAlO3 was prepared by immobilizing Er3＋：YAlO3/TiO2, which was obtained by combination of Er3＋：YAlO3 and TiO2 using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction （XRD）, energy dispersive X-ray spectra （EDS） analysis, scanning electron microscopy （SEM） and fluorescence spectra analysis （FSA）. The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange （MO） in aqueous solution under visible light irradiation from a LED lamp （λ400 nm）. The results showed that Er3＋：YAlO3 could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er3＋：YAlO3/TiO2 calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min-1 under visible light irradiation.
基金Project(50802034) supported by the National Natural Science Foundation of ChinaProject(11A093) supported by the Key Project Foundation by the Education Department of Hunan Province,China
文摘TiO2-coated activated carbon surface （TAs） composites were prepared by a sol-gel method with supercritical pretreatment. The photocatalytic degradation of acid yellow （AY） was investigated under UV radiation to estimate activity of catalysts and determine the kinetics. And the effects of parameters including the initial concentration of AY, light intensity and TiO2 content in catalysts were examined. The results indicate that TAs has a higher efficiency in decomposition of AY than P25, pure TiO2 particles as well as the mixture of TiO2 powder and active carbon. The photocatalytic degradation rate is found to follow the pseudo-first order kinetics with respect to the AY concentration. The new kinetic model fairly resembles the classic Langmuir-Hinshelwood equation, and the rate constant is proportional to the square root of the light intensity in a wide range. However, its absorption performance depends on the surface areas of catalysts. The model fits quite well with the experimental data and elucidates phenomena about the effects of the TiO2 content in TAs on the degradation rate.
基金supported by the National Natural Science Foundation of China(52376103,542B2081).
文摘The technology for green and macro-conversion of solid waste biomass to prepare high-quality activated carbon demands urgent development.This study proposes a technique for synthesizing carbon adsorbents using trace KOH-catalyzed CO_(2) activation.Comprehensive investigations were conducted on three aspects:physicochemical structure evolution of biochar,mechanistic understanding of trace KOH-facilitated CO_(2) activation processes,and application characteristics for CO_(2) adsorption.Results demonstrate that biochar activated by trace KOH(<10%)and CO_(2) achieves comparable specific surface area(1244.09 m^(2)/g)to that obtained with 100%KOH activation(1425.10 m^(2)/g).The pore structure characteristics(specific surface area and pore volume)are governed by CO and CH4 generated through K-salt catalyzed reactions between CO_(2) and biochar.The optimal CO_(2) adsorption capacities of KBC adsorbent reached 4.70 mmol/g(0℃)and 7.25 mmol/g(25℃),representing the maximum values among comparable carbon adsorbents.The 5%KBC-CO_(2) sample exhibited CO_(2) adsorption capacities of 3.19 and 5.01 mmol/g under respective conditions,attaining current average performance levels.Notably,CO_(2)/N_(2) selectivity(85∶15,volume ratio)reached 64.71 at 0.02 bar with robust cycling stability.Molecular dynamics simulations revealed that oxygen-containing functional groups accelerate CO_(2) adsorption kinetics and enhance micropore storage capacity.This technical route offers simplicity,environmental compatibility,and scalability,providing critical references for large-scale preparation of high-quality carbon materials.
基金financially supported by National High-Level Talent FundNational Natural Science Foundation of China (Nos. 22372138,22461160253,22121001,and 22072118)+3 种基金thank financial support from State Key Laboratory of Physical Chemistry of Solid Surfaces of Xiamen UniversityShenzhen Science and Technology Program (No. JCYJ20220530143401002)supported by Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM) (No. HRTP-[2022]-3)the Fundamental Research Funds for the Central Universities (No. 20720220008)
文摘The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts,while its symmetric charge distribution nature is not favorable for electron transfer and then hindering the efficient CO_(2)RR.Herein,we constructed a Ni SA/CNs single-atom catalyst.Notably,it features unique Ni-N_(4)-O active sites,featuring one axial O atom and four planar N atoms,constituting a broken symmetrical electronic structure of Ni-N_(4) sites.Furthermore,hierarchical pore structures were obtained with the assistance of NaNO_(3) pore-forming agent during thermal treatment process,which promote electronic and mass transfer.And the resulting high specific surface area can host more Ni-N_(4)-O active sites.These specialized active sites promote the key intermediate(∗CO)adsorption/desorption and suppresses hydrogen evolution.Consequently,the Ni SA/CNs catalyst exhibits a high turnover frequency(TOF)value,reaching 34,081 h^(-1) at-0.98 V vs.RHE.Additionally,it achieves an excellent CO Faradaic efficiency,exceeding 90%,over a wide potential range from-0.4 V to-1.0 V vs.RHE.This work not only offers a new method for the rational synthesize single-atom catalysts with unique Ni-N_(4)-O active sites,but also provides in-depth insight into the origin of catalytic activity of porous carbon-base catalysts.
基金supported financially by the National Natural Science Foundation of China (No.51301039)the Natural Science Foundation of Fujian Province (No.2016J01214)the Public Institutes Special Fund Project of Fujian Province (No.2016R10096)
文摘A new nanostructured amino-functionalized magnetic bacterial cellulose/activated carbon（BC/AC）composite bioadsorbent（AMBCAC）was prepared for removal of Pb^2＋ and methyl orange（MO）from aqueous solution.The results demonstrated that the equilibrium adsorption capacity（qe）for Pb^2＋ obviously increases by 2.14 times after introduction of amino groups,the optimum p H for Pb^2＋and MO adsorption was 5.0 and 3.0,respectively,and the qeof AMBCAC was 161.78 mg g^-1 for Pb^2＋ and 83.26 mg g^-1 for MO under the optimal conditions in this investigation.The kinetics and adsorption isotherm data of the sorption process were well fitted by pseudo-second-order kinetic model and Langmuir isotherm respectively.The thermodynamic results（the Gibbs free energy change G〈0,the enthalpy change H〉0,the entropy change S〉0）implied that the adsorption process of Pb^2＋ and MO was feasible,endothermic and spontaneous in nature.These results support that the AMBCAC composite developed in this work can provide a cheap and efficient way for easy removal of both Pb^2＋ and MO as a promising adsorbent candidate for wastewater treatment.
基金supported by the National Natural Science Foundation of China(No.20707009)the Jiangsu Province Social Development Foundation(No.BS2007051)+1 种基金the Opening Foundation(WTWER0713)of Engineering Research Center for Water Treatment and Water Remediation of the Ministry of Education of Chinathe State Key Laboratory of Pollution Control and Resource Reuse Opening Foundation(No.PCRRCF07003).
文摘The photocatalytic degradation of Rhodamine B(RhB)was carried out using TiO_(2)supported on activated carbon(TiO_(2)-AC)under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction(XRD),transmission electron microscopy(TEM)and Brunauer-Emmett-Teller(BET).In the process of microwave-enhanced photocatalysis(MPC),RhB(30 mg/L)was almost completely decoloured in 10 min,and the mineralization efficiency was 96.0%in 20 min.The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25.Additionally,according to gas chromatography/mass spectrometry(GC/MS)and liquid chromatography/mass spectrometry(LC/MS)identification,the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates(N,N-diethyl-N'-ethyl-rhodamine(DER)),oxalic acid,malonic acid,snccinic acid,and phthalic acid,maleic acid,3-nitrobenzoic acid,and so on.The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure,and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide.
基金supported by the Educational and Tech-nological Department of Hunan Province(No.08B063)the Natural Science Foundation of Science and Technology Department of Hunan Government(No.2007GK3060)the Doctor Foundation of Jishou University(No.JSDXKYZZ200648).
文摘The activated carbon-supported TiO2 nanoparticles(TiO2/AC)were prepared by a properly controlled sol-gel method.The effects of activated carbons(AC)support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments of Escherichia coli.The key factors affecting the inactivation effciency were investigated,including electric power of lamp, temperature,and pH values.The results show that the TiO2/AC composites have high inactivation properties of E.coli in compari...
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This work was supported by the National Natural Science Foundation of China(Nos.41530643 and 41807358)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14020203)the Joint Fund of NSFC and Henan(No.U1804110).
文摘The ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its performance for the uptake of arsenate and arsenite species from aqueous solutions was investigated by batch experiments.Various techniques,including FESEM-EDX,p-XRD,XPS and BET surface area analysis,were employed to characterize the properties of the adsorbent and the arsenic adsorption mechanisms.The results showed thatδ-MnO2 covered on the surface and padded in the pores of the activated carbon.Adsorption kinetic studies revealed that approximately 90.1%and 76.8%of As(Ⅲ)and As(V),respectively,were removed by the adsorbent in the first 9 hr,and adsorption achieved equilibrium within 48 hr.The maximum adsorption capacities of As(V)and As(Ⅲ)at pH 4.0 calculated from Langmuir adsorption isotherms were 13.30 and 12.56 mg/g,respectively.The effect of pH on As(Ⅴ)and As(Ⅲ)removal was similar,and the removal efficiency significantly reduced with the increase of solution pH.Arsenite oxidation and adsorption kinetics showed that the As(Ⅴ)concentration in solution due to As(Ⅲ)oxidation and reductive dissolution of MnO2 increased rapidly during the first 12 min,and then gradually decreased.Based on the XPS analysis,nearly 93.3%of As(Ⅲ)had been oxidized to As(V)on the adsorbent surface and around 38.9%of Mn(Ⅳ)had been reduced to Mn(Ⅱ)after As(Ⅲ)adsorption.This approach provides a possible method for the purification of arsenic-contaminated groundwater.
文摘Preparation of activated carbon from chicken waste is a promising way to produce a useful adsorbent for Hg removal. A three-stage activation process （drying at 200℃, pyrolysis in N2 atmosphere, followed by CO2 activation） was used for the production of activated samples. The effects of carbonization temperature （409-4500℃）, activation temperature （700-900℃）, and activation time （1-2.5 h） on the physicochemical properties （weight-loss and BET surface） of the prepared carbon wereinvestigated. Adsorptive removal of mercury from real flue gas onto activated carbon has been studied. The activated carbon from chicken waste has the same mercury capacity as commercial activated carbon （Darco LH） （Hg^v： 38.7% vs. 53.5%, Hg^0： 50.5% vs. 68.8%）, although its surface area is around 10 times smaller, 89.5 m^2/g vs. 862 m^2/g. The low cost activated carbon can be produced from chicken waste, and the procedure is suitable.
基金Project supported by West China Top Discipline Program in Basic Medicine Sciences,Ningxia Medical University,ChinaProject(21266026)supported by the National Natural Science Foundation of China
文摘Activated carbon obtained from Astragalus residue was chemically activated by KOH and modified with KMnO4.The samples were characterized by N2 adsorption,Fourier transform infrared spectroscopy,X-ray diffractometry,scanning electron microscopy,and Boehm titration.Accordingly,the original and modified carbon materials were used for the removal of Cd2+from aqueous solution by batch adsorption experiments.Results showed that the contents of oxygen-containing functional groups increased,and MnO2 was nearly uniformly deposited on the surface of activated carbon after modification by KMnO4.The adsorption kinetics was described by pseudo-second order model.Langmuir model fitted the adsorption-isotherm experimental data of Cd2+better than the Freundlich model.The maximum adsorption capacities of the activated carbon before and after modification for Cd2+were 116.96 and 217.00 mg/g,respectively.KMnO4 considerably changed the physicochemical properties and surface texture of activated carbon and enhanced the adsorption capacity of activated carbon for Cd2+.
基金The State Education Ministry "211" Project, the Natural Science Foundation of the Education Commission of Jiangsu Province(2005103TSJB156) and the Funding of the Environment Friendship Laboratory of Nanjing Normal University
文摘TiO2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO2 particles can be effectively suppressed by added polyethylene glycol （PEG） as a surface modifier. The average particle diameter of TiO2, specific surface area and absorbability of catalyst can be modified. Based on characteristics of the TiO2 photocatalyst with XRD, specific surface area, adsorption valves of methylene blue and the amount of TiO2 supported on the activated carbon, the photocatalytic degradation of L-acid was studied. The effect of the factors, such as pH of the solution, the initial concentration of L-acid on the photocatalytic degradation of L-acid, were studied also. It was found that when the pH of the solution is 1.95, the amount of photocatalyst is 0.5 g, the concentration of the L-acid solution is 1.34×10^3 mol/L and the illumination time is 7 h, the photocatalytic degradation efficiency of L-acid can reach 89,88%, The catalyst was reused 6 times and its degradation efficiency hardly changed.
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.
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.
文摘A series of oxidants supported on coconut shell-based activated carbon(CAC) through microwave irradiation were prepared and characterized using scanning electron microscopy(SEM), N_2 adsorption/desorption analysis, and X-ray photoelectron spectroscopy(XPS). The SO_2 adsorption capacities and rates were evaluated by adsorption tests performed in a fixed bed reactor with a simulated flue gas, and the adsorption isotherm models were validated against the experimental results. The findings revealed that the SO_2 adsorption capacity decreased in the following order: MW-K_2Cr_2O_7-CAC > MWKMnO_4-CAC > MW-H_2O_2-CAC > MW-CAC. The SO_2 adsorption capacities and adsorption rates of the samples increased with an increasing oxidizability of the oxidants owing to the increment of mean pore size and oxygen-containing functional groups. In addition, a high initial SO_2 concentration and a low bed temperature could positively affect the SO2 adsorption. Finally, the Langmuir model validated that SO_2 was mainly adsorbed through chemical adsorption on the sample surfaces.
基金supported by the National Natural Science Foundation of China(52276195)Program for Supporting Innovative Research from Jinan(202228072)Program of Agricultural Development from Shandong(SD2019NJ015)。
文摘Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce dehydration and/or aromatization to change the structure of cellulose/hemicellulose.This might interfere with evolution of structures of AC,which was investigated herein via thermal pretreatment of willow branch(WB)from 200 to 360℃and the subsequent activation with ZnCl_(2) at 550℃.The results showed that thermal pretreatment at 360℃(WB-360)could lead to substantial pyrolysis to form biochar,with a yield of 31.9%,accompanying with nearly complete destruction of cellulose crystals and remarkably enhanced aromatic degree.However,cellulose residual in WB-360 could still be activated to form AC-360 with specific surface area of 1837.9 m~2·g^(-1),which was lower than that in AC from activation of untreated WB(AC-blank,2077.8 m~2·g^(-1)).Nonetheless,the AC-200 from activation of WB-200 had more developed pores(2113.9 m~2·g^(-1))and superior capability for adsorption of phenol,due to increased permeability of ZnCl_(2) to the largely intact cellulose structure in WB-200.The thermal pretreatment did increase diameters of micropores of AC but reduced the overall yield of AC(26.8%for AC-blank versus 18.0%for AC-360),resulting from accelerated cracking but reduced intensity of condensation.In-situ infrared characterization of the activation showed that ZnCl_(2) mainly catalyzed dehydration,dehydrogenation,condensation,and aromatization but not cracking,suppressing the formation of derivatives of cellulose and lignin in bio-oil.The thermal pretreatment formed phenolic-OH and C=O with higher chemical innerness,which changed the reaction network in activation,shifting morphology of fibrous structures in AC-blank to“melting surface”in AC-200 or AC-280.
基金Supported by the National Natural Science Foundation of China(21506194,21676255)the Natural Science Foundation of Zhejiang Province(Y16B070025)the Commission of Science and Technology of Zhejiang Province(2013C03021,2017C33106)
文摘An activated carbon pore-expanding technique was achieved through innovative reactivation by CO_2/microwave.The original and modified activated carbons were characterized by nitrogen adsorption–desorption,scanning electron microscopy,transmission electron microcopy,and Fourier transform infrared spectroscopy.The mesopore volume increased from 0.122 cm^3·g^(-1) to 0.270 cm^3·g^(-1),and a hierarchical pore structure was formed.A gradual decrease in the phenolic hydroxyl and carboxyl groups on the surface of activated carbon enhanced the surface inertia of granular activated carbon(GAC).The toluene desorption rate of the modified sample increased by 8.81% compared with that of the original GAC.Adsorption isotherm fittings revealed that the Langmuir model was applicable for the original and modified activated carbons.The isosteric adsorption heat of toluene on the activated carbon decreased by approximately 50%,which endowed the modified sample with excellent stability in application.The modified samples showed an enhanced desorption performance of toluene,thereby opening a way to extend the cycle life and improve the economic performance of carbon adsorbent in practical engineering applications.
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.
基金support by the National Natural Science Foundation of China (No. 20776150)the National Hi-Tech Research and Development Program of China(No. 2008AA05Z308)the Special Fund for Basic Scientific Research of Central Colleges (No. 2009QH15)
文摘The role of Nil（NO3）2 in the preparation of a magnetic activated carbon is reported in this paper. Magnetic coal-based activated carbons （MCAC） were prepared from Taixi anthracite with low ash content in the presence of Ni（NO3）2. The MCAC materials were characterized by a vibrating sample magnetometer （VSM）, X-ray diffraction （XRD）, a scanning electric microscope （SEM）, and by N2 adsorption. The cylindri- cal precursors and derived char were also subjected to thermogravimetric analysis to compare their behavior of weight losses during carbonization. The results show that MCAC has a larger surface area （1074 m21g） and a higher pore volume （0.5792 cm3/g） with enhanced mesopore ratio （by about 10~）. It also has a high saturation magnetization （1.6749 emu/g） and low coercivity （43.26 Oe）, which allows the material to be magnetically separated. The MCAC is easily magnetized because the nickel salt is con- vetted into Ni during carbonization and activation. Metallic Ni has a strong magnetism on account of electrostatic interaction. Added Ni（NO3）2 catalyzes the carbonization and activation process by accelerat- ing burn off of the carbon, which contributes to the development of mesopores and macropores in the activated carbon.
