In recent years,machine learning(ML)techniques have demonstrated a strong ability to solve highly complex and non-linear problems by analyzing large datasets and learning their intrinsic patterns and relationships.Par...In recent years,machine learning(ML)techniques have demonstrated a strong ability to solve highly complex and non-linear problems by analyzing large datasets and learning their intrinsic patterns and relationships.Particularly in chemical engineering and materials science,ML can be used to discover microstructural composition,optimize chemical processes,and create novel synthetic pathways.Electrochemical processes offer the advantages of precise process control,environmental friendliness,high energy conversion efficiency and low cost.This review article provides the first systematic summary of ML in the application of electrochemical oxidation,including pollutant removal,battery remediation,substance synthesis and material characterization prediction.Hot trends at the intersection of ML and electrochemical oxidation were analyzed through bibliometrics.Common ML models were outlined.The role of ML in improving removal efficiency,optimizing experimental conditions,aiding battery diagnosis and predictive maintenance,and revealing material characterization was highlighted.In addition,current issues and future perspectives were presented in relation to the strengths and weaknesses of ML algorithms applied to electrochemical oxidation.In order to further support the sustainable growth of electrochemistry from basic research to useful applications,this review attempts to make it easier to integrate ML into electrochemical oxidation.展开更多
Electrochemical advanced oxidation processes (EAOPs) are effective and environmentally friendly for the treatment of refractory organic pollutants.Among EAOPs,heterogeneous electro-Fenton (EF) process with in-situ for...Electrochemical advanced oxidation processes (EAOPs) are effective and environmentally friendly for the treatment of refractory organic pollutants.Among EAOPs,heterogeneous electro-Fenton (EF) process with in-situ formation of hydrogen peroxide (H_(2)O_(2)) is an eco-friendly,cost-effective and easy-operable technology to generate hydroxyl radicals (;OH) with high redox potential.The generation of;OH is determined by the synergistic H_(2)O_(2)formation and activation.The surface catalytic mechanisms for H_(2)O_(2)activation in the heterogeneous EF process were discussed.Some required features such as heteroatom doping and oxygen groups for H_(2)O_(2)formation via selective two-electron oxygen reduction reaction (ORR) with carbonaceous electrode are summarized.The solid Fenton catalysts and integrated functional cathodes that widely used in heterogeneous EF for wastewater treatment are grouped into few classes.And the brief discussion on catalytic activity and stability of materials over different experimental conditions are given.In addition,the application of heterogeneous EF process on the remediation of emerging contaminants is provided.The challenges and future prospects of the heterogeneous EF processes about catalytic fall-off and multi-step/complex techniques for water purification are emphasized.展开更多
Photochemical aging of volatile organic compounds(VOCs)in the atmosphere is an important source of secondary organic aerosol(SOA).To evaluate the formation potential of SOA at an urban site in Lyon(France),an outdoor ...Photochemical aging of volatile organic compounds(VOCs)in the atmosphere is an important source of secondary organic aerosol(SOA).To evaluate the formation potential of SOA at an urban site in Lyon(France),an outdoor experiment using a Potential Aerosol Mass(PAM)oxidation flow reactor(OFR)was conducted throughout entire days during JanuaryFebruary 2017.Diurnal variation of SOA formations and their correlation with OH radical exposure(OHexp),ambient pollutants(VOCs and particulate matters,PM),Relative Humidity(RH),and temperature were explored in this study.Ambient urban air was exposed to high concentration of OH radicals with OHexp in range of(0.2-1.2)×10^12 molecule/(cm^3·sec),corresponding to several days to weeks of equivalent atmospheric photochemical aging.The results informed that urban air at Lyon has high potency to contribute to SOA,and these SOA productions were favored from OH radical photochemical oxidation rather than via ozonolysis.Maximum SOA formation(36μg/m^3)was obtained at OHexp of about 7.4×10^11 molecule/(cm^3·sec),equivalent to approximately 5 days of atmospheric oxidation.The correlation between SOA formation and ambient environment conditions(RH&temperature,VOCs and PM)was observed.It was the first time to estimate SOA formation potential from ambient air over a long period in urban environment of Lyon.展开更多
Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOxremoval and HONO formation,having profound impacts on photochemistry in polluted urban areas.Previous studies have suggeste...Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOxremoval and HONO formation,having profound impacts on photochemistry in polluted urban areas.Previous studies have suggested that the NO2 uptake on the ground or aerosol surfaces could be a dominant source for elevated HONO during the daytime.However,the uptake behavior of NO2 varies with different surfaces,and different uptake coefficients were used or derived in different studies.To obtain a more holistic picture of heterogeneous NO2 uptake on different surfaces,a series of laboratory experiments using different flow tube reactors was conducted,and the NO2 uptake coefficients(γ)were determined on inorganic particles,sea water and urban grime.The results showed that heterogeneous reactions on those surfaces were generally weak in dark conditions,with the measuredγvaried from<10-8 to 3.2×10-7 under different humidity.A photo-enhanced uptake of NO2 on urban grime was observed,with the obvious formation of HONO and NO from the heterogeneous reaction.The photo-enhancedγwas measured to be 1.9×10-6 at 5%relative humidity(RH)and 5.8×10-6 at 70%RH on urban grime,showing a positive RH dependence for both NO2 uptake and HONO formation.The results demonstrate an important role of urban grime in the daytime NO2-to-HONO conversion,and could be helpful to explain the unknown daytime HONO source in the polluted urban area.展开更多
Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results revea...Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results reveal that the Mg_3 CeO_x catalyst is present in the form of Mg-Ce-O solid solution,while the Mg3 LaOx and Mg_3 YO_x catalysts are probably rare earth oxides dispersed on MgO surface. As a result, among the calcined Mg_3 REO_x catalysts, the Mg_3 CeO_x catalyst presents the highest rate constant for acetone aldolization, which is well correlated to its more homogeneous distribution of basic sites. In contrary, the Mg_3 YO_x catalyst exhibit the lowest catalytic activity for acetone aldolization. Upon hydration pre-treatment, the basic properties on the surface of the Mg_3 REO_x catalysts were changed markedly. The Mg_3 YO_x catalyst after hydration treatment shows the highest amount of basic sites on catalyst surface, and then exhibits the highest activity among the hydrated Mg_3 REO_x catalysts. These results make it possible to fine-tune basic sites for acetone aldolization.展开更多
The advanced oxidation processes were examined toward the degradation of thymine （CsH6N202）, a type of nucleic acid from the pyrimidine family. As observed, the photodegradation of thymine over TiO2 photocatalyst wa...The advanced oxidation processes were examined toward the degradation of thymine （CsH6N202）, a type of nucleic acid from the pyrimidine family. As observed, the photodegradation of thymine over TiO2 photocatalyst was rapid and significant in aqueous solution under UV irradiation. Different parameters were studied, including the adsorption of thymine onto TiO2 photocatalyst, the kinetics of degradation, and the effect of pH on the photocatalytic properties of thymine degradation. Additionally, the mineralization of the products obtained upon thymine photodegradation was studied. The disappearance and mineralization rates of thymine during the photocatalytic process were also compared and discussed. The mineralization of nitrogen was also investigated, and the identification of the intermediate products was established. Finally, electronic density calculations were used to propose possible chemical pathways for the photodegradation of thymine over TiO2 photocatalyst under UV irradiation.展开更多
Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica(June 2011).Aimedat assessing the performance on the field ...Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica(June 2011).Aimedat assessing the performance on the field of newly developed analytical protocols,this work focuses on the molecular composition of both gas and particulate phases and provides an insight into partitioning behavior of the semi-volatile oxygenated fraction.Limonene ozonolysis tracers were specifically searched for,according to gas chromatography–mass spectrometry(GC–MS)data previously recorded for smog chamber experiments.A screening of other oxygenated species present in the field atmosphere was also performed.About sixty polar molecules were positively or tentatively identified in gas and/or particle phases.These molecules comprise a wide range of branched and linear,mono and di-carbonyls(C_3–C7),mono and di-carboxylic acids(C_3–C_18),and compounds bearing up to three functionalities.Among these compounds,some can be specifically attributed to limonene oxidation and others can be related toα-orβ-pinene oxidation.This provides an original snapshot of the organic matter composition at a Mediterranean site in summer.Furthermore,for compounds identified and quantified in both gaseous and particulate phases,an experimental gas/particle partitioning coefficient was determined.Several volatile products,which are not expected in the particulate phase assuming thermodynamic equilibrium,were nonetheless present in significant concentrations.Hypotheses are proposed to explain these observations,such as the possible aerosol viscosity that could hinder the theoretical equilibrium to be rapidly reached.展开更多
Nighttime aqueous oxidation of fossil fuel emissions is a significant source of atmospheric secondary organic aerosols.However,the underlying mechanism of the aqueous processing remains unclear.Utilizing ultrahigh-res...Nighttime aqueous oxidation of fossil fuel emissions is a significant source of atmospheric secondary organic aerosols.However,the underlying mechanism of the aqueous processing remains unclear.Utilizing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry of watersoluble organic carbon samples,we present field observations that reveal the aqueous-phase conversion of nitroaromatic compounds(NACs)and sulfur-containing aerosols from fossil fuel combustion at high relative humidity during a severe haze event in Beijing in the winter of 2016.We have confirmed that the ring-breaking oxidation of NACs can generate nitrous acid in the aqueous phase,which rapidly oxidizes sulfur dioxide(SO_(2))to sulfate.Subsequently,reactions between sulfate and unsaturated compounds contribute to the formation of aliphatic organosulfates.Our results elucidate a molecular-level understanding of the aqueous production of sulfur-containing aerosols from NACs and SO_(2) in wintertime urban haze.展开更多
Wet air oxidation （WAO） and catalytic wet air oxidation （CWAO） are efficient processes to degrade organic pollutants in water. In this paper, we especially reviewed the WAO and CWAO processes for phenolic compound...Wet air oxidation （WAO） and catalytic wet air oxidation （CWAO） are efficient processes to degrade organic pollutants in water. In this paper, we especially reviewed the WAO and CWAO processes for phenolic compounds degradation. It provides a comprehensive introduction to the CWAO processes that could be beneficial to the scientists entering this field of research. The influence of different reaction parameters, such as temperature, oxygen pressure, pH, stirring speed are analyzed in detail; Homogenous catalysts and heterogeneous catalysts including carbon materials, transitional metal oxides and noble metals are extensively discussed, among which Cu based catalysts and Ru catalysts were shown to be the most active. Three different kinds of the reactor implemented for the CWAO （autoclave, packed bed and membrane reactors） are illustrated and compared. To enhance the degradation efficiency and reduce the cost of the CWAO process, biological degradation can be combined to develop an integrated technology.展开更多
Fully palladium/copper catalytic oxidative cross-coupling of acrylates with α-methylstyrene was performed in a DMSO/AcOH(1:1) mixture at 60℃ in the air.This improves previous procedures which employed stoichiometric...Fully palladium/copper catalytic oxidative cross-coupling of acrylates with α-methylstyrene was performed in a DMSO/AcOH(1:1) mixture at 60℃ in the air.This improves previous procedures which employed stoichiometric amounts of copper and oxygen.Thus various acrylates were effectively coupled to α-methylstyrene giving the expected compounds in moderate to good yields(44%-65%) as a mixture of E and Z isomers.展开更多
The paper describes the experiments conducted to create shape controllable preparations of submicronic cad- mium tetrazole-based MOFs. In order to prepare the submicron sized blocks and tubes of bis[5-（2-pyridyltetra...The paper describes the experiments conducted to create shape controllable preparations of submicronic cad- mium tetrazole-based MOFs. In order to prepare the submicron sized blocks and tubes of bis[5-（2-pyridyltetrazo- lato）]diaquacadmium（II） [（2-PTZ）2Cd（H20）2] MOFs both solvothermal and microwave augmented reaction proce- dures have been followed. Cadmium nitrate tetrahydrate, cyanopyridine and sodium azide were used as reactants in both the conditions without any surfactants or modulators. Subsequently, IR spectroscopy and single-crystal X-ray crystallographic studies were performed on the prepared MOFs. Examinations using scanning electron microscopy and X-ray powder diffraction of the products made by the microwave method showed formation of bundles of reg- ular submicrotubes, as opposed to the submicron-sized irregular blocks of the Cd-MOF obtained through the sol- vothermal method. The fluorescence peak of the sub-microtube MOF was found at 460 nm while the irregu- lar-blocks emitted at 442 nm indicating a red shift for the former. In addition, the relative intensity of the peak at 460 nm was higher in the former, indicating a decrease in the crystallite size. Band gaps of the MOFs calculated by using the Tauc plots were 2.87 and 2.73 eV, respectively. Their photocatalytic performances using methylene blue under UV-vis irradiation have been investigated.展开更多
The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation （CWAO） of cationic red GTL under mild operating conditions in a batch reactor. T...The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation （CWAO） of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area （BET measurement）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. The Fe203-CeO2-]]i203/qt-A1203 catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions （catalyst loading, degradation temperature, solution concentration and initial solution pH value） was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ. mo1-1. Hydroperoxy radicals （HO2.） and superoxide radicals （O2-） appeared as the main reactive species upon the CWAO of cationic red GTL.展开更多
In the recent years, photocatalytic self-cleaning and ＂depolluting＂ materials have been suggested as a remediation technology mainly for NOx and aromatic VOCs in urban areas. A number of products incorporating the a...In the recent years, photocatalytic self-cleaning and ＂depolluting＂ materials have been suggested as a remediation technology mainly for NOx and aromatic VOCs in urban areas. A number of products incorporating the aforementioned technology have been made commercially available with the aim to improve urban air quality. These commercial products are based on the photocatalytic properties of a thin layer of TiO2 at the surface of the material （such as glass, pavement, etc.） or embedded in paints or concrete. The use of TiO2 photocatalysts as an emerging air pollution control technology has been reported in many locations worldwide. However, up to now, the effectiveness measured in situ and theexpected positive impact on air quality of this relatively new technology has only been demonstrated in a limited manner. Assessing and demonstrating the effectiveness of these depolluting techniques in real scale applications aims to create a real added value, in terms of policy making （i.e., implementing air quality strategies） and economics （by providing a demonstration of the actual performance of a new technique）.展开更多
基金funding from the National Natural Science Foundation of China(Nos.22122606,22076142,62276190)National Key Basic Research Program of China(No.2017YFA0403402)+2 种基金National Natural Science Foundation of China(No.U1932119)the Science&Technology Commission of Shanghai Municipality(No.14DZ2261100)the Fundamental Research Funds for the Central Universities。
文摘In recent years,machine learning(ML)techniques have demonstrated a strong ability to solve highly complex and non-linear problems by analyzing large datasets and learning their intrinsic patterns and relationships.Particularly in chemical engineering and materials science,ML can be used to discover microstructural composition,optimize chemical processes,and create novel synthetic pathways.Electrochemical processes offer the advantages of precise process control,environmental friendliness,high energy conversion efficiency and low cost.This review article provides the first systematic summary of ML in the application of electrochemical oxidation,including pollutant removal,battery remediation,substance synthesis and material characterization prediction.Hot trends at the intersection of ML and electrochemical oxidation were analyzed through bibliometrics.Common ML models were outlined.The role of ML in improving removal efficiency,optimizing experimental conditions,aiding battery diagnosis and predictive maintenance,and revealing material characterization was highlighted.In addition,current issues and future perspectives were presented in relation to the strengths and weaknesses of ML algorithms applied to electrochemical oxidation.In order to further support the sustainable growth of electrochemistry from basic research to useful applications,this review attempts to make it easier to integrate ML into electrochemical oxidation.
基金funding from the National Natural Science Foundation of China (Nos.22076142,21677106,22076140)National Key Basic Research Program of China (No.2017YFA0403402)+2 种基金National Natural Science Foundation of China (No.U1932119)the Science & Technology Commission of Shanghai Municipality (No.14DZ2261100)the Fundamental Research Funds for the Central Universities。
文摘Electrochemical advanced oxidation processes (EAOPs) are effective and environmentally friendly for the treatment of refractory organic pollutants.Among EAOPs,heterogeneous electro-Fenton (EF) process with in-situ formation of hydrogen peroxide (H_(2)O_(2)) is an eco-friendly,cost-effective and easy-operable technology to generate hydroxyl radicals (;OH) with high redox potential.The generation of;OH is determined by the synergistic H_(2)O_(2)formation and activation.The surface catalytic mechanisms for H_(2)O_(2)activation in the heterogeneous EF process were discussed.Some required features such as heteroatom doping and oxygen groups for H_(2)O_(2)formation via selective two-electron oxygen reduction reaction (ORR) with carbonaceous electrode are summarized.The solid Fenton catalysts and integrated functional cathodes that widely used in heterogeneous EF for wastewater treatment are grouped into few classes.And the brief discussion on catalytic activity and stability of materials over different experimental conditions are given.In addition,the application of heterogeneous EF process on the remediation of emerging contaminants is provided.The challenges and future prospects of the heterogeneous EF processes about catalytic fall-off and multi-step/complex techniques for water purification are emphasized.
基金the Institute for Research on Catalysis and the Environment of Lyon(IRCELYON)supported by the"Investissement d’Avenir"PEPS Program Project(ASTRAL)of the University of Lyon and French National center for Scientific Research(French:center national de la recherche scientifique,CNRS)as part of the ANR-11-IDEX-0007 programby the European Research Council under the Horizon 2020 Research and Innovation Program Project of the European Union under Convention N°690958(MARSU)。
文摘Photochemical aging of volatile organic compounds(VOCs)in the atmosphere is an important source of secondary organic aerosol(SOA).To evaluate the formation potential of SOA at an urban site in Lyon(France),an outdoor experiment using a Potential Aerosol Mass(PAM)oxidation flow reactor(OFR)was conducted throughout entire days during JanuaryFebruary 2017.Diurnal variation of SOA formations and their correlation with OH radical exposure(OHexp),ambient pollutants(VOCs and particulate matters,PM),Relative Humidity(RH),and temperature were explored in this study.Ambient urban air was exposed to high concentration of OH radicals with OHexp in range of(0.2-1.2)×10^12 molecule/(cm^3·sec),corresponding to several days to weeks of equivalent atmospheric photochemical aging.The results informed that urban air at Lyon has high potency to contribute to SOA,and these SOA productions were favored from OH radical photochemical oxidation rather than via ozonolysis.Maximum SOA formation(36μg/m^3)was obtained at OHexp of about 7.4×10^11 molecule/(cm^3·sec),equivalent to approximately 5 days of atmospheric oxidation.The correlation between SOA formation and ambient environment conditions(RH&temperature,VOCs and PM)was observed.It was the first time to estimate SOA formation potential from ambient air over a long period in urban environment of Lyon.
基金supported by the French National Research Agency/Research Grants Council of Hong Kong Special Administrative Region,China(ANR/RGC)Joint Research Scheme(project A-PolyU502/16-SEAM)National Natural Science Foundation of China(Nos.91744204,91844301)+1 种基金the Research Grants Council of Hong Kong Special Administrative Region,China(Nos.T24/504/17,15265516,C5022-14G)。
文摘Heterogeneous reactions of NO2 on different surfaces play an important role in atmospheric NOxremoval and HONO formation,having profound impacts on photochemistry in polluted urban areas.Previous studies have suggested that the NO2 uptake on the ground or aerosol surfaces could be a dominant source for elevated HONO during the daytime.However,the uptake behavior of NO2 varies with different surfaces,and different uptake coefficients were used or derived in different studies.To obtain a more holistic picture of heterogeneous NO2 uptake on different surfaces,a series of laboratory experiments using different flow tube reactors was conducted,and the NO2 uptake coefficients(γ)were determined on inorganic particles,sea water and urban grime.The results showed that heterogeneous reactions on those surfaces were generally weak in dark conditions,with the measuredγvaried from<10-8 to 3.2×10-7 under different humidity.A photo-enhanced uptake of NO2 on urban grime was observed,with the obvious formation of HONO and NO from the heterogeneous reaction.The photo-enhancedγwas measured to be 1.9×10-6 at 5%relative humidity(RH)and 5.8×10-6 at 70%RH on urban grime,showing a positive RH dependence for both NO2 uptake and HONO formation.The results demonstrate an important role of urban grime in the daytime NO2-to-HONO conversion,and could be helpful to explain the unknown daytime HONO source in the polluted urban area.
基金Project supported by National Basic Research Program of China(2010CB732300)111 Project(B08021)China Scholarship Council for the Joint-Training Scholarship Program with Institut de Recherches sur la Catalyse et l'Environnement de Lyon(IRCELYON)and Universite Claude Bernard Lyon 1(UCBL1)
文摘Magnesium and rare earth mixed oxides（Mg3 REOx（RE=La, Y. Ce）） were prepared and characterized by Xray diffraction（XRD）, N_2 adsorption-desorption, infrared spectra and microcalorimetry of CO_2. The results reveal that the Mg_3 CeO_x catalyst is present in the form of Mg-Ce-O solid solution,while the Mg3 LaOx and Mg_3 YO_x catalysts are probably rare earth oxides dispersed on MgO surface. As a result, among the calcined Mg_3 REO_x catalysts, the Mg_3 CeO_x catalyst presents the highest rate constant for acetone aldolization, which is well correlated to its more homogeneous distribution of basic sites. In contrary, the Mg_3 YO_x catalyst exhibit the lowest catalytic activity for acetone aldolization. Upon hydration pre-treatment, the basic properties on the surface of the Mg_3 REO_x catalysts were changed markedly. The Mg_3 YO_x catalyst after hydration treatment shows the highest amount of basic sites on catalyst surface, and then exhibits the highest activity among the hydrated Mg_3 REO_x catalysts. These results make it possible to fine-tune basic sites for acetone aldolization.
基金supported by The French Institute of Tunisia and University of Gabes,Tunisia (Scientific Stay High Level 2015)
文摘The advanced oxidation processes were examined toward the degradation of thymine （CsH6N202）, a type of nucleic acid from the pyrimidine family. As observed, the photodegradation of thymine over TiO2 photocatalyst was rapid and significant in aqueous solution under UV irradiation. Different parameters were studied, including the adsorption of thymine onto TiO2 photocatalyst, the kinetics of degradation, and the effect of pH on the photocatalytic properties of thymine degradation. Additionally, the mineralization of the products obtained upon thymine photodegradation was studied. The disappearance and mineralization rates of thymine during the photocatalytic process were also compared and discussed. The mineralization of nitrogen was also investigated, and the identification of the intermediate products was established. Finally, electronic density calculations were used to propose possible chemical pathways for the photodegradation of thymine over TiO2 photocatalyst under UV irradiation.
文摘Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica(June 2011).Aimedat assessing the performance on the field of newly developed analytical protocols,this work focuses on the molecular composition of both gas and particulate phases and provides an insight into partitioning behavior of the semi-volatile oxygenated fraction.Limonene ozonolysis tracers were specifically searched for,according to gas chromatography–mass spectrometry(GC–MS)data previously recorded for smog chamber experiments.A screening of other oxygenated species present in the field atmosphere was also performed.About sixty polar molecules were positively or tentatively identified in gas and/or particle phases.These molecules comprise a wide range of branched and linear,mono and di-carbonyls(C_3–C7),mono and di-carboxylic acids(C_3–C_18),and compounds bearing up to three functionalities.Among these compounds,some can be specifically attributed to limonene oxidation and others can be related toα-orβ-pinene oxidation.This provides an original snapshot of the organic matter composition at a Mediterranean site in summer.Furthermore,for compounds identified and quantified in both gaseous and particulate phases,an experimental gas/particle partitioning coefficient was determined.Several volatile products,which are not expected in the particulate phase assuming thermodynamic equilibrium,were nonetheless present in significant concentrations.Hypotheses are proposed to explain these observations,such as the possible aerosol viscosity that could hinder the theoretical equilibrium to be rapidly reached.
基金supported by the National Natural Science Foundation of China(42130513,42221001,22276099,and U24A20515)the Harvard-NUIST Joint Laboratory on Air Quality and Climate(JLAQC)。
文摘Nighttime aqueous oxidation of fossil fuel emissions is a significant source of atmospheric secondary organic aerosols.However,the underlying mechanism of the aqueous processing remains unclear.Utilizing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry of watersoluble organic carbon samples,we present field observations that reveal the aqueous-phase conversion of nitroaromatic compounds(NACs)and sulfur-containing aerosols from fossil fuel combustion at high relative humidity during a severe haze event in Beijing in the winter of 2016.We have confirmed that the ring-breaking oxidation of NACs can generate nitrous acid in the aqueous phase,which rapidly oxidizes sulfur dioxide(SO_(2))to sulfate.Subsequently,reactions between sulfate and unsaturated compounds contribute to the formation of aliphatic organosulfates.Our results elucidate a molecular-level understanding of the aqueous production of sulfur-containing aerosols from NACs and SO_(2) in wintertime urban haze.
文摘Wet air oxidation （WAO） and catalytic wet air oxidation （CWAO） are efficient processes to degrade organic pollutants in water. In this paper, we especially reviewed the WAO and CWAO processes for phenolic compounds degradation. It provides a comprehensive introduction to the CWAO processes that could be beneficial to the scientists entering this field of research. The influence of different reaction parameters, such as temperature, oxygen pressure, pH, stirring speed are analyzed in detail; Homogenous catalysts and heterogeneous catalysts including carbon materials, transitional metal oxides and noble metals are extensively discussed, among which Cu based catalysts and Ru catalysts were shown to be the most active. Three different kinds of the reactor implemented for the CWAO （autoclave, packed bed and membrane reactors） are illustrated and compared. To enhance the degradation efficiency and reduce the cost of the CWAO process, biological degradation can be combined to develop an integrated technology.
基金the National Agency of Research (CATAQ N° ANR-07-CP2D-0167-01/02) for funding
文摘Fully palladium/copper catalytic oxidative cross-coupling of acrylates with α-methylstyrene was performed in a DMSO/AcOH(1:1) mixture at 60℃ in the air.This improves previous procedures which employed stoichiometric amounts of copper and oxygen.Thus various acrylates were effectively coupled to α-methylstyrene giving the expected compounds in moderate to good yields(44%-65%) as a mixture of E and Z isomers.
文摘The paper describes the experiments conducted to create shape controllable preparations of submicronic cad- mium tetrazole-based MOFs. In order to prepare the submicron sized blocks and tubes of bis[5-（2-pyridyltetrazo- lato）]diaquacadmium（II） [（2-PTZ）2Cd（H20）2] MOFs both solvothermal and microwave augmented reaction proce- dures have been followed. Cadmium nitrate tetrahydrate, cyanopyridine and sodium azide were used as reactants in both the conditions without any surfactants or modulators. Subsequently, IR spectroscopy and single-crystal X-ray crystallographic studies were performed on the prepared MOFs. Examinations using scanning electron microscopy and X-ray powder diffraction of the products made by the microwave method showed formation of bundles of reg- ular submicrotubes, as opposed to the submicron-sized irregular blocks of the Cd-MOF obtained through the sol- vothermal method. The fluorescence peak of the sub-microtube MOF was found at 460 nm while the irregu- lar-blocks emitted at 442 nm indicating a red shift for the former. In addition, the relative intensity of the peak at 460 nm was higher in the former, indicating a decrease in the crystallite size. Band gaps of the MOFs calculated by using the Tauc plots were 2.87 and 2.73 eV, respectively. Their photocatalytic performances using methylene blue under UV-vis irradiation have been investigated.
文摘The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation （CWAO） of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area （BET measurement）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. The Fe203-CeO2-]]i203/qt-A1203 catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions （catalyst loading, degradation temperature, solution concentration and initial solution pH value） was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ. mo1-1. Hydroperoxy radicals （HO2.） and superoxide radicals （O2-） appeared as the main reactive species upon the CWAO of cationic red GTL.
文摘In the recent years, photocatalytic self-cleaning and ＂depolluting＂ materials have been suggested as a remediation technology mainly for NOx and aromatic VOCs in urban areas. A number of products incorporating the aforementioned technology have been made commercially available with the aim to improve urban air quality. These commercial products are based on the photocatalytic properties of a thin layer of TiO2 at the surface of the material （such as glass, pavement, etc.） or embedded in paints or concrete. The use of TiO2 photocatalysts as an emerging air pollution control technology has been reported in many locations worldwide. However, up to now, the effectiveness measured in situ and theexpected positive impact on air quality of this relatively new technology has only been demonstrated in a limited manner. Assessing and demonstrating the effectiveness of these depolluting techniques in real scale applications aims to create a real added value, in terms of policy making （i.e., implementing air quality strategies） and economics （by providing a demonstration of the actual performance of a new technique）.
