Non-thermal plasma(NTP)is considered to be a promising technology for the removal of volatile organic compounds;however,its application is limited by low CO_(2) selectivity and undesirable by-products.To overcome thes...Non-thermal plasma(NTP)is considered to be a promising technology for the removal of volatile organic compounds;however,its application is limited by low CO_(2) selectivity and undesirable by-products.To overcome these issues,this paper discusses the degradation of chlorobenzene(CB)in systems of NTP coupled with catalysts,and the influence of catalyst locations in the NTP was investigated.In addition,the interaction between plasma and catalyst was also explored.The results indicated that the degradability of CB was remarkably improved through the combination of NTP with catalysts,and the formation of ozone was effectively inhibited.The degradation efficiency increased from 33.9%to 79.6%at 14 kV in the NTPcatalytic system,while the ozone concentration decreased from 437 to 237 mg m^(-3),and the degradation efficiency of in plasma catalysis(IPC)systems was superior to that of the post plasma catalysis system,while the inhibition ability of ozone exhibited an opposing trend.In the IPC system,the degradation efficiency was 87.7%at 14 k V,while the ozone concentration was151 mg m^(-3).Besides,the plasma did not destroy the pore structure and crystal structure of the catalyst,but affected the surface morphology and redox performance of the catalyst.Thus,NTP coupled catalytic system could improve the degradation performance of CB.Furthermore,the plasma discharge characteristics played a major role in the NTP synergistic catalytic degradation of CB.Finally,based on the experiment analysis results,the general reaction mechanism of CB degradation in an IPC reaction system was proposed.展开更多
This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentratio...This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentration on CB degradation were determined.The degradation effciency of CB was almost 100% with an initial CB concentration of 50 mg/L,current density 15 mA/cm2,initial pH 10,electrolyte concentration 0.1 mol/L,and temperature 25°C after 90 min of reaction.Under the same conditions,the degradation effciency of CB was only 51% by electrochemical (EC) process,which showed that electro-heterogeneous catalysis was more effcient than EC alone.The analysis results of Purge-and-Trap chromatography-mass spectrometry (P&T/GC/MS) and ion chromatography (IC) indicated that in the reaction process,the initial .OH attack could occur at the C-Cl bond of CB,yielding phenol and biphenyl with the release of Cl-.Further oxidation of phenol and biphenyl produced ρ-Vinylbenzoic acid and hydroquinol.Finally,the compounds were oxidized to butenedioic acid and other small-molecule acids.展开更多
Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a mo...Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a modified Rose-Williams still. Gas chromatography was used to analyze the compositions of the samples and no azeotropic behavior was found. All of the measured VLE values were checked by the semi-empirical method proposed by Herington and the point-to-point Van Ness test method modified by Fredenslund. The experimental data were correlated by using the Wilson, the non-random two-liquid and universal quasi-chemical activity coefficient models. The corresponding parameters for the three models were obtained.展开更多
The thermal decomposition of Cyclic Diperoxide of Benzaldehyde 3,6-diphenyl-1,2,4,5-tetroxane, (DFT) in chlorobenzene solution in the studied temperature range (130°C - 166°C) satisfactorily satisfies a firs...The thermal decomposition of Cyclic Diperoxide of Benzaldehyde 3,6-diphenyl-1,2,4,5-tetroxane, (DFT) in chlorobenzene solution in the studied temperature range (130°C - 166°C) satisfactorily satisfies a first order law up to 60% conversions of diperoxide. DFT would decompose through a mechanism in stages and initiated by the homolytic breakdown of one of the peroxidic bonds of the molecule, with the formation of the corresponding intermediate biradical. The concentration studied was very low, so that the effects of secondary reactions of decomposition induced by free radicals originated in the reaction medium can be considered minimal or negligible. The activation parameters for the unimolecular thermal decomposition reaction of the DFT are ΔH# = 30.52 ± 0.3 kcal·mol-1 and ΔS# = -6.38 ± 0.6 cal·mol-1 K-1. The support for a step-by-step mechanism instead of a process concerted is made by comparison with the theoretically calculated activation energy for the thermal decomposition of 1,2,4,5-tetroxane.展开更多
Objective To evaluate the effect of white rot fungus Phanerochaete chrysosporium on removal of gaseous chlorobenzene. Methods Fungal mycelium mixed with a liquid medium was placed into airtight bottles. A certain amou...Objective To evaluate the effect of white rot fungus Phanerochaete chrysosporium on removal of gaseous chlorobenzene. Methods Fungal mycelium mixed with a liquid medium was placed into airtight bottles. A certain amount of chlorobenzene was injected into the headspace of the bottles under different conditions. At a certain interval, the concentrations in the headspace were analyzed to evaluate the degradation of chlorobenzene by P. chrysosporium. Results The degradation effects of P. chrysosporium on chlorobenzene under different conditions were investigated. The difference in the optimum temperature for the growth of the fungi and chlorobenzene degradation was observed. The data indicated that a lower temperature (28℃) would promote the degradation of chlorobenzene than the optimum temperature for the growth of the fungi (37℃). A low nitrogen source concentration (30 mg N/L) had a better effect on degrading chlorobenzene than a high nitrogen source concentration (higher than 100 mg N/L). A high initial concentration (over 1100 mg/m3) of chlorobenzene showed an inhibiting effect on degradation by P. chrysosporium. A maximum removal efficiency of 95% was achieved at the initial concentration of 550 mg/m3. Conclusion P. chrysosporium has a rather good ability to remove gaseous chlorobenzene. A low nitrogen source concentration and a low temperature promote the removal of chlorobenzene by P. chrysosporium. However, a high initial chlorobenzene concentration can inhibit chlorobenzene degradation.展开更多
Chlorobenzene was dechlorinated by Pd/Fe bimetallic system in water through catalytic reduction. The dechlorination rate increases with increase of bulk loading of Pd due to the increase of both the surface loading of...Chlorobenzene was dechlorinated by Pd/Fe bimetallic system in water through catalytic reduction. The dechlorination rate increases with increase of bulk loading of Pd due to the increase of both the surface loading of the Pd and the total surface area. For conditions with 0.005% Pd/Fe, 45% dechlorination efficiency was achieved within 5 h. The dechlorinated reaction is believed to take place on the bimetal surface in a pseudo-first-order reaction, with the rate constant being 0.0043 min-1.展开更多
Catalytic reductive dechlorination of monochlorobenzene(MCB) was carried out in the palladium/iron system. With low Pd loading(0 005%), 45% dechlorination efficiency was achieved within 5 h. Pd as catalyst accelerated...Catalytic reductive dechlorination of monochlorobenzene(MCB) was carried out in the palladium/iron system. With low Pd loading(0 005%), 45% dechlorination efficiency was achieved within 5 h. Pd as catalyst accelerated the reductive dechlorination reaction. Dechlorination mechanism and kinetics were discussed. The reaction took place on the bimetal surface in a pseudo first order reaction, with the rate constant being 0 0071 min -1 ( K SA =8 0×10 -3 L/(m 2·h). The reduction product for MCB was benzene.展开更多
Paratungstate-loaded titania catalysts were prepared %via% the addition of a series of aqueous solutions of paratungstate(denoted as W_ 7) into an isopropanol solution of Ti[OCH(CH_ 3)_ 2]_ 4 by means of the sol-gel m...Paratungstate-loaded titania catalysts were prepared %via% the addition of a series of aqueous solutions of paratungstate(denoted as W_ 7) into an isopropanol solution of Ti[OCH(CH_ 3)_ 2]_ 4 by means of the sol-gel method. The catalysts were characterized by EDX, BET, FTIR, UV-Vis DRS, XRD and the results indicate that such paratungstate-loaded catalysts maintained their heptatungstate structure in the anatase titania matrix up to 400 ℃. The catalysts were tested for the heterogeneous photodegradation of chlorobenzene in aqueous media and showed a better catalytic activity than P-25 TiO_ 2 because paratungstate can prevent the recombination of the holes and electrons produced during irradiation. Moreover, the paratungstate-loaded titania catalysts can resist the disaggregation during the photoirradiation and can be easily recycled from the aqueous suspensions after reactions.展开更多
[Objective]The research aimed to study the effect of underground temperature on the adsorption behavior of chlorobenzene under artificial recharge condition. [Method]Based on the prior researches,combining actual cond...[Objective]The research aimed to study the effect of underground temperature on the adsorption behavior of chlorobenzene under artificial recharge condition. [Method]Based on the prior researches,combining actual condition of the artificial recharge test site,the adsorption behavior of chlorobenzene under the background of artificial recharge was discussed. [Result]The adsorption reaction of chlorobenzene corresponded with quasi-first-order and quasi-second-order kinetics equations at certain concentration. When temperature rose,reaction rate accelerated,and adsorption balance time shortened to 12 (0 ℃) ,10 (10 ℃) and 8 (20 ℃) h. The adsorption of chlorobenzene corresponded with isothermal adsorption model very well at different concentrations. When temperature ranged from 0 to 20 ℃,the adsorption amount of medium on chlorobenzene increased at equilibrium time. The maximal adsorption amounts calculated by Langmuir model were 20. 747, 21. 505, 23. 364 μg/g at 0,10 and 20 ℃, respectively. [Conclusion]The adsorption of chlorobenzene in aquifer medium was endothermic reaction,and the best season of artificial recharge was in summer.展开更多
The reaction of 3-nitro-4-chlorobenzenesulfinic acid and ethylene oxide to obtain 2-nitro-4-(β-hydroxyethylsulfonyl)chlorobenzene had been studied. Except hydroxyethylation on the sulfur atom of 3-nitro-4-chlorobenze...The reaction of 3-nitro-4-chlorobenzenesulfinic acid and ethylene oxide to obtain 2-nitro-4-(β-hydroxyethylsulfonyl)chlorobenzene had been studied. Except hydroxyethylation on the sulfur atom of 3-nitro-4-chlorobenzenesulfinic acid to form the target product, 2-nitro-4-(β- hydroxyethylsulfonyl)chlorobenzene, there presented three kinds of side reactions: 1. Condensa- tion and elimination of HCl to form biphenyl sulfone derivatives; 2. Addition to give bisulfonyl ethane derivative via vinyl sulfone; and 3. Hydroxylethylation on O-atom to produce hydroxylethyl- sulfinate due to the tautomerism of sulfinic acid.展开更多
In this study,the improvement in the removal of chlorobenzene (C_6H_5Cl) in the airwas investigated by combining dielectric barrier discharge (DBD) driven by bipolar pulse-powerwith catalysts.Molecular sieve 4A (MS-4A...In this study,the improvement in the removal of chlorobenzene (C_6H_5Cl) in the airwas investigated by combining dielectric barrier discharge (DBD) driven by bipolar pulse-powerwith catalysts.Molecular sieve 4A (MS-4A) and MnO_2/γ-Al_2O_3 (MnO_2/ALP) an two kinds ofcatalysts were tested at different positions in a DBD reactor.Catalysts were located either in thedischarging area between two electrodes,or just behind the discharging area (in the afterglow area)cloned to the outlet.The results indicated that DBD reactor with a bipolar pulse power-supplyproduced strong instant discharge and energetic particles,which can effectively activate catalystsof MS-4A and MnO_2/ALP located in the afterglow area to achieve the synergistic effects oneffective fission of chemical bonds of chlorobenzene.It wan considered that the gas-chlorobenzeneand the chlorobenzene adsorbed on the catalysts were decomposed simultaneously.展开更多
Here,a metal-organic framework(MOF)-templated strategy was applied to synthesize the CoCeO_(x) bimetallic catalysts by calcining Co partially-substituted Ce-UiO-66.It is indicated that the substituted Co limited Ce ca...Here,a metal-organic framework(MOF)-templated strategy was applied to synthesize the CoCeO_(x) bimetallic catalysts by calcining Co partially-substituted Ce-UiO-66.It is indicated that the substituted Co limited Ce cations in Ce-UiO-66 framework,which affects its growth and structure crystallinity to some extent.After pyrolysis treatment,the derived bimetallic oxide(CoCeO_(x)-M)can basically keep the octahedral structure and the surface area is much higher than the bulk metal composite oxide(CoCeO_(x)-B)prepared by traditional coprecipitation.Results reveal that CoCeO_(x)-M performs the best chlorobenzene degradation capacity,superior stability and vapor tolerance compared with those of CeO_(2)-M(derived from Ce-UiO-66)and CoCeO_(x)-B.At the same time,it is favorable to inhibit the formation of CO during the oxidation reaction.The superior catalytic performance of CoCeO_(x)-M is attributed to a good dispersion of metal cations,high surface area and active oxygen concentration,and good redox property.Moreover,the formation of organic byproducts especially chlorinated organics can be obviously prohibited over CoCeO_(x)-M compared with that of CeO_(2)-M.Mechanism study reveals that chlorobenzene dissociates on the surface of CoCeO_(x)-M to form carboxylates such as acetate species,maleate and phenolate before finally oxidized into CO_(2),H_(2)O,and HCl.The present work poses new insights into the fabrication of efficient catalysts for industrial CVOC purification.展开更多
In this work,hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH_(4))_(2)C_(2)O_(4)as a novel nitroge...In this work,hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH_(4))_(2)C_(2)O_(4)as a novel nitrogen-doping agent.Physicochemical properties of NPCK-x were characterized by Brunauer-Emmett-Teller,field emission scanning electron microscopy,X-ray diffraction,Raman microscope,elemental analysis,and X-ray photoelectron spectroscopy.Results showed that the NPCK-x samples possessed large surface areas (maximum:2875 m^(2)/g),hierarchical porous structures,and high degree of disorder.N-containing functional groups decomposed during activation process,which could be the dominant reason for appearance of abundant mesopores and well-developed pore structure.Dynamic chlorobenzene adsorption experiments demonstrated that carbon materials with(NH_(4))_(2)C_(2)O_(4)modification exhibited higher adsorption capacity (maximum:1053 mg/g) than those without modification (maximum:723 mg/g).The reusability studies of chlorobenzene indicated that the desorption efficiency of (NH_(4))_(2)C_(2)O_(4)modified porous carbon reached90.40%after thermal desorption at 100℃ under N2atmosphere.Thomas model fitting results exhibited that the existence of mesopores accelerated the diffusion rate of chlorobenzene in porous carbon.Moreover,Grand Canonical Monte Carlo simulation was conducted to verify that micropores with pore sizes of 1.2–2 nm of the optimized porous carbon were the best adsorption sites for chlorobenzene and mesopores with pore sizes of 2–5 nm were also highly active sites for chlorobenzene adsorption.展开更多
Despite the large emission of chlorinated volatile organic compounds(CVOCs)into the atmosphere,the ultimate fate of these compounds remains largely unknown.Herein,we explore the photochemical conversion of an importan...Despite the large emission of chlorinated volatile organic compounds(CVOCs)into the atmosphere,the ultimate fate of these compounds remains largely unknown.Herein,we explore the photochemical conversion of an important class of CVOCs,namely chlorobenzene(CB),on mineralα-Fe_(2)O_(3)particulates under atmospheric relevant conditions.A series of chamber reactions composed of the CB with/without SO_(2)or NO_(2)are performed,followed by in situ diffuse reflectance infrared Fourier transform spectroscopy measurements and density functional theory calculations.We show that CB can be considerably degraded byα-Fe_(2)O_(3)under light irradiation,whereas the reaction is markedly suppressed by adding SO_(2)or NO_(2)owing to their competitive adsorption and surface acidification.In particular,we discover that CB can be ultimately converted into polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)under dark state or light irradiation,suggesting a possible origin of atmospheric PCDD/Fs from this overlooked photochemical source.展开更多
基金supported by the National Key Research and Development Program of China(No.2018YFC1903100)Beijing Municipal Science and Technology Project Program(No.Z191100009119002)the State Environmental Protection Key Laboratory of Odor Pollution Control(No.20210504)。
文摘Non-thermal plasma(NTP)is considered to be a promising technology for the removal of volatile organic compounds;however,its application is limited by low CO_(2) selectivity and undesirable by-products.To overcome these issues,this paper discusses the degradation of chlorobenzene(CB)in systems of NTP coupled with catalysts,and the influence of catalyst locations in the NTP was investigated.In addition,the interaction between plasma and catalyst was also explored.The results indicated that the degradability of CB was remarkably improved through the combination of NTP with catalysts,and the formation of ozone was effectively inhibited.The degradation efficiency increased from 33.9%to 79.6%at 14 kV in the NTPcatalytic system,while the ozone concentration decreased from 437 to 237 mg m^(-3),and the degradation efficiency of in plasma catalysis(IPC)systems was superior to that of the post plasma catalysis system,while the inhibition ability of ozone exhibited an opposing trend.In the IPC system,the degradation efficiency was 87.7%at 14 k V,while the ozone concentration was151 mg m^(-3).Besides,the plasma did not destroy the pore structure and crystal structure of the catalyst,but affected the surface morphology and redox performance of the catalyst.Thus,NTP coupled catalytic system could improve the degradation performance of CB.Furthermore,the plasma discharge characteristics played a major role in the NTP synergistic catalytic degradation of CB.Finally,based on the experiment analysis results,the general reaction mechanism of CB degradation in an IPC reaction system was proposed.
基金the Science and Technology Department of Zhejiang Province (No.2006C13120).
文摘This study was performed to investigate the variables that influence chlorobenzene (CB) degradation in aqueous solution by electro-heterogeneous catalysis.The effects of current density,pH,and electrolyte concentration on CB degradation were determined.The degradation effciency of CB was almost 100% with an initial CB concentration of 50 mg/L,current density 15 mA/cm2,initial pH 10,electrolyte concentration 0.1 mol/L,and temperature 25°C after 90 min of reaction.Under the same conditions,the degradation effciency of CB was only 51% by electrochemical (EC) process,which showed that electro-heterogeneous catalysis was more effcient than EC alone.The analysis results of Purge-and-Trap chromatography-mass spectrometry (P&T/GC/MS) and ion chromatography (IC) indicated that in the reaction process,the initial .OH attack could occur at the C-Cl bond of CB,yielding phenol and biphenyl with the release of Cl-.Further oxidation of phenol and biphenyl produced ρ-Vinylbenzoic acid and hydroquinol.Finally,the compounds were oxidized to butenedioic acid and other small-molecule acids.
基金supported by State Key Laboratory of Chemical Engineering Foundation
文摘Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a modified Rose-Williams still. Gas chromatography was used to analyze the compositions of the samples and no azeotropic behavior was found. All of the measured VLE values were checked by the semi-empirical method proposed by Herington and the point-to-point Van Ness test method modified by Fredenslund. The experimental data were correlated by using the Wilson, the non-random two-liquid and universal quasi-chemical activity coefficient models. The corresponding parameters for the three models were obtained.
文摘The thermal decomposition of Cyclic Diperoxide of Benzaldehyde 3,6-diphenyl-1,2,4,5-tetroxane, (DFT) in chlorobenzene solution in the studied temperature range (130°C - 166°C) satisfactorily satisfies a first order law up to 60% conversions of diperoxide. DFT would decompose through a mechanism in stages and initiated by the homolytic breakdown of one of the peroxidic bonds of the molecule, with the formation of the corresponding intermediate biradical. The concentration studied was very low, so that the effects of secondary reactions of decomposition induced by free radicals originated in the reaction medium can be considered minimal or negligible. The activation parameters for the unimolecular thermal decomposition reaction of the DFT are ΔH# = 30.52 ± 0.3 kcal·mol-1 and ΔS# = -6.38 ± 0.6 cal·mol-1 K-1. The support for a step-by-step mechanism instead of a process concerted is made by comparison with the theoretically calculated activation energy for the thermal decomposition of 1,2,4,5-tetroxane.
基金supported by the Hi-tech Research and Development Program of China (2004AA601061).
文摘Objective To evaluate the effect of white rot fungus Phanerochaete chrysosporium on removal of gaseous chlorobenzene. Methods Fungal mycelium mixed with a liquid medium was placed into airtight bottles. A certain amount of chlorobenzene was injected into the headspace of the bottles under different conditions. At a certain interval, the concentrations in the headspace were analyzed to evaluate the degradation of chlorobenzene by P. chrysosporium. Results The degradation effects of P. chrysosporium on chlorobenzene under different conditions were investigated. The difference in the optimum temperature for the growth of the fungi and chlorobenzene degradation was observed. The data indicated that a lower temperature (28℃) would promote the degradation of chlorobenzene than the optimum temperature for the growth of the fungi (37℃). A low nitrogen source concentration (30 mg N/L) had a better effect on degrading chlorobenzene than a high nitrogen source concentration (higher than 100 mg N/L). A high initial concentration (over 1100 mg/m3) of chlorobenzene showed an inhibiting effect on degradation by P. chrysosporium. A maximum removal efficiency of 95% was achieved at the initial concentration of 550 mg/m3. Conclusion P. chrysosporium has a rather good ability to remove gaseous chlorobenzene. A low nitrogen source concentration and a low temperature promote the removal of chlorobenzene by P. chrysosporium. However, a high initial chlorobenzene concentration can inhibit chlorobenzene degradation.
文摘Chlorobenzene was dechlorinated by Pd/Fe bimetallic system in water through catalytic reduction. The dechlorination rate increases with increase of bulk loading of Pd due to the increase of both the surface loading of the Pd and the total surface area. For conditions with 0.005% Pd/Fe, 45% dechlorination efficiency was achieved within 5 h. The dechlorinated reaction is believed to take place on the bimetal surface in a pseudo-first-order reaction, with the rate constant being 0.0043 min-1.
文摘Catalytic reductive dechlorination of monochlorobenzene(MCB) was carried out in the palladium/iron system. With low Pd loading(0 005%), 45% dechlorination efficiency was achieved within 5 h. Pd as catalyst accelerated the reductive dechlorination reaction. Dechlorination mechanism and kinetics were discussed. The reaction took place on the bimetal surface in a pseudo first order reaction, with the rate constant being 0 0071 min -1 ( K SA =8 0×10 -3 L/(m 2·h). The reduction product for MCB was benzene.
文摘Paratungstate-loaded titania catalysts were prepared %via% the addition of a series of aqueous solutions of paratungstate(denoted as W_ 7) into an isopropanol solution of Ti[OCH(CH_ 3)_ 2]_ 4 by means of the sol-gel method. The catalysts were characterized by EDX, BET, FTIR, UV-Vis DRS, XRD and the results indicate that such paratungstate-loaded catalysts maintained their heptatungstate structure in the anatase titania matrix up to 400 ℃. The catalysts were tested for the heterogeneous photodegradation of chlorobenzene in aqueous media and showed a better catalytic activity than P-25 TiO_ 2 because paratungstate can prevent the recombination of the holes and electrons produced during irradiation. Moreover, the paratungstate-loaded titania catalysts can resist the disaggregation during the photoirradiation and can be easily recycled from the aqueous suspensions after reactions.
基金Supported by National Natural Science Foundation Project, China (41103045) "Science Frontier and Interdiscipline Innovation Project" ,Jilin University, China (201003031)
文摘[Objective]The research aimed to study the effect of underground temperature on the adsorption behavior of chlorobenzene under artificial recharge condition. [Method]Based on the prior researches,combining actual condition of the artificial recharge test site,the adsorption behavior of chlorobenzene under the background of artificial recharge was discussed. [Result]The adsorption reaction of chlorobenzene corresponded with quasi-first-order and quasi-second-order kinetics equations at certain concentration. When temperature rose,reaction rate accelerated,and adsorption balance time shortened to 12 (0 ℃) ,10 (10 ℃) and 8 (20 ℃) h. The adsorption of chlorobenzene corresponded with isothermal adsorption model very well at different concentrations. When temperature ranged from 0 to 20 ℃,the adsorption amount of medium on chlorobenzene increased at equilibrium time. The maximal adsorption amounts calculated by Langmuir model were 20. 747, 21. 505, 23. 364 μg/g at 0,10 and 20 ℃, respectively. [Conclusion]The adsorption of chlorobenzene in aquifer medium was endothermic reaction,and the best season of artificial recharge was in summer.
文摘The reaction of 3-nitro-4-chlorobenzenesulfinic acid and ethylene oxide to obtain 2-nitro-4-(β-hydroxyethylsulfonyl)chlorobenzene had been studied. Except hydroxyethylation on the sulfur atom of 3-nitro-4-chlorobenzenesulfinic acid to form the target product, 2-nitro-4-(β- hydroxyethylsulfonyl)chlorobenzene, there presented three kinds of side reactions: 1. Condensa- tion and elimination of HCl to form biphenyl sulfone derivatives; 2. Addition to give bisulfonyl ethane derivative via vinyl sulfone; and 3. Hydroxylethylation on O-atom to produce hydroxylethyl- sulfinate due to the tautomerism of sulfinic acid.
基金This project was supported by the National Basic Research Program of China （No. 2007CB936602） and the Natural Science Foundation of Shandong Province in China （No. Y2008B20）.
基金National Natural Science Foundation of China(No.50678031)
文摘In this study,the improvement in the removal of chlorobenzene (C_6H_5Cl) in the airwas investigated by combining dielectric barrier discharge (DBD) driven by bipolar pulse-powerwith catalysts.Molecular sieve 4A (MS-4A) and MnO_2/γ-Al_2O_3 (MnO_2/ALP) an two kinds ofcatalysts were tested at different positions in a DBD reactor.Catalysts were located either in thedischarging area between two electrodes,or just behind the discharging area (in the afterglow area)cloned to the outlet.The results indicated that DBD reactor with a bipolar pulse power-supplyproduced strong instant discharge and energetic particles,which can effectively activate catalystsof MS-4A and MnO_2/ALP located in the afterglow area to achieve the synergistic effects oneffective fission of chemical bonds of chlorobenzene.It wan considered that the gas-chlorobenzeneand the chlorobenzene adsorbed on the catalysts were decomposed simultaneously.
基金Project supported by the National Natural Science Foundation of China(22106124,22276145)the Natural Science Foundation of Shaanxi Province(2021JQ-011).
文摘Here,a metal-organic framework(MOF)-templated strategy was applied to synthesize the CoCeO_(x) bimetallic catalysts by calcining Co partially-substituted Ce-UiO-66.It is indicated that the substituted Co limited Ce cations in Ce-UiO-66 framework,which affects its growth and structure crystallinity to some extent.After pyrolysis treatment,the derived bimetallic oxide(CoCeO_(x)-M)can basically keep the octahedral structure and the surface area is much higher than the bulk metal composite oxide(CoCeO_(x)-B)prepared by traditional coprecipitation.Results reveal that CoCeO_(x)-M performs the best chlorobenzene degradation capacity,superior stability and vapor tolerance compared with those of CeO_(2)-M(derived from Ce-UiO-66)and CoCeO_(x)-B.At the same time,it is favorable to inhibit the formation of CO during the oxidation reaction.The superior catalytic performance of CoCeO_(x)-M is attributed to a good dispersion of metal cations,high surface area and active oxygen concentration,and good redox property.Moreover,the formation of organic byproducts especially chlorinated organics can be obviously prohibited over CoCeO_(x)-M compared with that of CeO_(2)-M.Mechanism study reveals that chlorobenzene dissociates on the surface of CoCeO_(x)-M to form carboxylates such as acetate species,maleate and phenolate before finally oxidized into CO_(2),H_(2)O,and HCl.The present work poses new insights into the fabrication of efficient catalysts for industrial CVOC purification.
基金supported by the National Key Research and Development Program of China (No.2019YFC1805804)。
文摘In this work,hydrothermal technique combined with KOH activation were employed to develop a series of porous carbons (NPCK-x) using tobacco stem as a low-cost carbon source and (NH_(4))_(2)C_(2)O_(4)as a novel nitrogen-doping agent.Physicochemical properties of NPCK-x were characterized by Brunauer-Emmett-Teller,field emission scanning electron microscopy,X-ray diffraction,Raman microscope,elemental analysis,and X-ray photoelectron spectroscopy.Results showed that the NPCK-x samples possessed large surface areas (maximum:2875 m^(2)/g),hierarchical porous structures,and high degree of disorder.N-containing functional groups decomposed during activation process,which could be the dominant reason for appearance of abundant mesopores and well-developed pore structure.Dynamic chlorobenzene adsorption experiments demonstrated that carbon materials with(NH_(4))_(2)C_(2)O_(4)modification exhibited higher adsorption capacity (maximum:1053 mg/g) than those without modification (maximum:723 mg/g).The reusability studies of chlorobenzene indicated that the desorption efficiency of (NH_(4))_(2)C_(2)O_(4)modified porous carbon reached90.40%after thermal desorption at 100℃ under N2atmosphere.Thomas model fitting results exhibited that the existence of mesopores accelerated the diffusion rate of chlorobenzene in porous carbon.Moreover,Grand Canonical Monte Carlo simulation was conducted to verify that micropores with pore sizes of 1.2–2 nm of the optimized porous carbon were the best adsorption sites for chlorobenzene and mesopores with pore sizes of 2–5 nm were also highly active sites for chlorobenzene adsorption.
基金supported by the National Natural Science Foundation of China(No.22176169,52070168)the Key R&D Plan of Zhejiang Province(No.2023C03127)the Fundamental Research Funds for the Central Universities(No.226-2022-00150).
文摘Despite the large emission of chlorinated volatile organic compounds(CVOCs)into the atmosphere,the ultimate fate of these compounds remains largely unknown.Herein,we explore the photochemical conversion of an important class of CVOCs,namely chlorobenzene(CB),on mineralα-Fe_(2)O_(3)particulates under atmospheric relevant conditions.A series of chamber reactions composed of the CB with/without SO_(2)or NO_(2)are performed,followed by in situ diffuse reflectance infrared Fourier transform spectroscopy measurements and density functional theory calculations.We show that CB can be considerably degraded byα-Fe_(2)O_(3)under light irradiation,whereas the reaction is markedly suppressed by adding SO_(2)or NO_(2)owing to their competitive adsorption and surface acidification.In particular,we discover that CB can be ultimately converted into polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)under dark state or light irradiation,suggesting a possible origin of atmospheric PCDD/Fs from this overlooked photochemical source.
