Methanotrophs in marine sediments and overlying water attenuate the emissions of methane into the atmosphere and thus play an important role for the global cycle of this greenhouse gas.However,gas released from natura...Methanotrophs in marine sediments and overlying water attenuate the emissions of methane into the atmosphere and thus play an important role for the global cycle of this greenhouse gas.However,gas released from natural hydrocarbon seeps are not pure methane but commonly mixed hydrocarbons.Currently,how methanotrophic bacteria behave in the co-presence of methane and heavier hydrocarbons remains unknown.In this paper,the bacteria were cultured aerobically in fresh sediment samples(collected from Bohai Bay in eastern China)at 28℃under the atmospheres of pure methane and methane+ethane+propane mixed gas,respec-tively.The prevailing terrigenous n-alkanes and fatty acids in the original sediment samples varied consistently after incubations,confirming the proceeding of aerobic bacterial activities.The real-time quantitative PCR assay and sequencing of the 16S rRNA and particulate methane monooxygenase(pmoA)genes revealed the changes of microbe communities to a methanotroph-dominating structure after incubations.Particularly,after incubations the family Methylococcaceae(typeⅠmethanotrophs)became dominant with proportions higher than 40%,whereas Methylocystaceae(typeⅡmethanotrophs)nearly disappeared in all incubated samples.More-over,the species of methanotrophs from the samples treated with pure methane were dominated by Methylobacter luteus,whereas Methylobacter whittenburyi took the predominant proportion in the samples treated with mixed gas.The phenomenon suggests that some methanotrophs may also utilize ethane and propane.Collectively,this study may help to gain a better understanding of the ef-fects and contributions of microbial activities in marine hydrocarbon seep ecosystems.展开更多
Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional external heating. This phenomenon is important in the development o...Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional external heating. This phenomenon is important in the development of catalytic combustion and catalytic partial oxidation processes, both of which have received extensive attention in recent years. In addition, catalytic ignition studies provide experimental data which can be used to test theoretical hydrocarbon oxidation models. For these reasons, catalytic ignition has been frequently studied. This review summarizes the experimental methods used to study catalytic ignition of light hydrocarbons and describes the experimental and theoretical results obtained related to catalytic ignition. The role of catalyst metal, fuel and fuel concentration, and catalyst state in catalytic ignition are examined, and some conclusions are drawn on the mechanism of catalytic ignition.展开更多
Metalloporphyrins immobilized into NaY zeolite are described as catalysts for hydrocarbon oxyfuntionalization. Manganese(III) and iron(III)tetrakis(4-N-methylpyridyl)-porphyrin (MnP1 and FeP1), and manganese(III) and ...Metalloporphyrins immobilized into NaY zeolite are described as catalysts for hydrocarbon oxyfuntionalization. Manganese(III) and iron(III)tetrakis(4-N-methylpyridyl)-porphyrin (MnP1 and FeP1), and manganese(III) and iron(III) tetrakis(4-N-benzylpiridil)-porphyrin (MnP2 and FeP2) were impregnated (MnP1-NaYimp, FeP1-NaYimp, MnP2-NaYimp, FeP2-NaYimp, respectively) and encapsulated (MnP1-NaY, FeP1-NaY, MnP2-NaY and FeP2-NaY) into the NaY zeolite. These catalysts were used in the oxidation of (Z)-cyclooctene, cyclohexane, and adamantane by iodosylbezene (PhIO). These systems were able to epoxidize (Z)-cyclooctene with cis-epoxycyclooctane yields as high as 100%. By using cyclohexane and adamantane as substrate, the susceptibility of the benzyl groups on the porphyrin ring of the MnP materials, led to a different distribution of the oxidized products. With FePs, this susceptibility was not detected because the species responsible for the oxidations, FeIV(O)P·+, is more active than MnV(O)P. In conclusion, cationic metalloporphyrins immobilized into NaX zeolites, are good cytochrome P-450 models is less polar solvents since the selectivity of the system indicates the “in cage” solvent oxygen rebound oxidative process.展开更多
The performance of a lubricant largely depends on the additives it involves. However, currently used additives cause severe pollution if they are burned and exhausted. Therefore, it is necessary to develop a new gener...The performance of a lubricant largely depends on the additives it involves. However, currently used additives cause severe pollution if they are burned and exhausted. Therefore, it is necessary to develop a new generation of green additives. Graphene oxide(GO) consists of only C, H and O and thus is considered to be environmentally friendly. So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically. It is found that, with the addition of GO sheets, both the coefficient of friction(COF) and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction. Moreover, GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%. After rubbing, GO is detected on the wear scars through Raman spectroscopy. And it is believed that, during the rubbing, GO sheets adhere to the sliding surfaces, behaving like protective films and preventing the sliding surfaces from contacting with each other directly. This paper proves that the GO sheet is an effective lubricant additive, illuminates the lubrication mechanism, and provides some critical parameters for the practical application of GO sheets in lubrication.展开更多
Following consideration of the characteristics of high temperature,high pressure and high in-situ stress in ultradeep sedimentary basins,together with the existence of hydrocarbon phase state transformation,hydrocarbo...Following consideration of the characteristics of high temperature,high pressure and high in-situ stress in ultradeep sedimentary basins,together with the existence of hydrocarbon phase state transformation,hydrocarbon-water-rock interaction and rock mechanical property transition at those depths,the evaluation index system for hydrocarbon preservation was established.The physical leakage evaluation indexes can be divided into three categories:the dynamic efficiency indexes of micro-sealing,caprock integrity and natural gas diffusion.The chemical loss evaluation indexes can be divided into two categories:the thermochemical sulfate reduction(TSR)index in marine gypsum-bearing carbonate strata and the thermochemical oxidation of hydrocarbons(TOH)index in clastic strata.The slippage angle and overconsolidation ratio(OCR)are the key evaluation indexes in the evaluation of the integrity of shale caprocks.TSR intensity can be quantitatively calculated by use of the Zn PVT state parameter method.The TOH strength can be used to estimate the degree of hydrocarbon chemical loss,based on the TOH-related authigenic calcite cement content or the degree of negativeδ^(13)C of authigenic calcite.For the evaluation of ultra-deep preservation in specific areas,key indexes can be selected according to the local geological conditions,instead of all indexes needing to be evaluated for every scenario.展开更多
Hybrid organic-inorganic silica materials containing organic functional groups have been preparedby the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane...Hybrid organic-inorganic silica materials containing organic functional groups have been preparedby the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane. The hybrid silica was further modified by organic compounds having abifunctional group. These modified hybrid silicas were used as catalysts for various nucleophilic reactions.And also, these were complexed with metallic ions for use as catalysts for oxygen oxidation of hydrocarbons.展开更多
In this study,graphene oxide was covalently immobilized on silica-coated magnetite and then modified with 2-phenylethylamine to give a nanocomposite of type Fe3O4@SiO2@GO-PEA that can be applied to the magnetic solid-...In this study,graphene oxide was covalently immobilized on silica-coated magnetite and then modified with 2-phenylethylamine to give a nanocomposite of type Fe3O4@SiO2@GO-PEA that can be applied to the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons(PAHs) from water samples.The resulting microspheres(Fe3O4@SiO2@GO-PEA) were characterized by Fourier transform-infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),CHNS elemental analysis,and vibrating sample magnetometry(VSM) techniques.The adsorbent possesses the magnetic properties of Fe3O4 nanoparticles that allow them easily to be separated by an external magnetic field.They also have the high specific surface area of graphene oxide which improves adsorption capacity.Desorption conditions,extraction time,amount of adsorbent,salt concentration,and pH were investigated and optimized.Following desorption,the PAHs were quantified by gas chromatography with flame ionization detection(GC-FID).The limits of detection(at an S/N ratio of 3) were achieved from 0.005 to0.1 μg/L with regression coefficients(R2) higher than 0.9954.The relative standard deviations(RSDs) were below 5.8%(intraday) and 6.2%(inter-day),respectively.The method was successfully applied to the analysis of PAHs in environmental water samples where it showed recoveries in the range between 71.7%and 106.7%(with RSDs of 1.6%to 8.4%,for n = 3).The results indicated that the Fe3O4@SiO2@GO-PEA microspheres had a great promise to extraction of PAHs from different water samples.展开更多
In recent decades,the environmental protection and long-term sustainability have become the focus of attention due to the increasing pollution generated by the intense industrialization.To overcome these issues,enviro...In recent decades,the environmental protection and long-term sustainability have become the focus of attention due to the increasing pollution generated by the intense industrialization.To overcome these issues,environmental catalysis has increasingly been used to solve the negative impact of pollutants emission on the global environment and human health.Supported platinum-metal-group(PGM)materials are commonly utilized as the state-of-the-art catalysts to eliminate gaseous pollutants but large quantities of PGMs are required.By comparison,single-atom site catalysts(SACs)have attracted much attention in catalysis owing to their 100%atom efficiency and unique catalytic performances towards various reactions.Over the past decade,we have witnessed burgeoning interests of SACs in heterogeneous catalysis.However,to the best of our knowledge,the systematic summary and analysis of SACs in catalytic elimination of environmental pollutants has not yet been reported.In this paper,we summarize and discuss the environmental catalysis applications of SACs.Particular focus was paid to automotive and stationary emission control,including model reaction(CO oxidation,NO reduction and hydrocarbon oxidation),overall reaction(three-way catalytic and diesel oxidation reaction),elimination of volatile organic compounds(formaldehyde,benzene,and toluene),and removal/decomposition of other pollutants(Hg0 and SO3).Perspectives related to further challenges,directions and design strategies of single-atom site catalysts in environmental catalysis were also provided.展开更多
A total of 15 light-duty diesel vehicles(LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hy...A total of 15 light-duty diesel vehicles(LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons(HC) and nitrogen oxides(NOx) at different speeds, chemical species profiles and ozone formation potential(OFP) of volatile organic compounds(VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOxhad been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOxemissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%–45.2%, followed by aromatics and alkenes. The most abundant species were propene,ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity(MIR)method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%–91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene.展开更多
基金This work was supported by the Natural Science Foun-dation of Shandong Province(No.ZR2020QD070)the National Natural Science Foundation of China(No.41876051)the China Geological Survey Project(No.DD 20190221).
文摘Methanotrophs in marine sediments and overlying water attenuate the emissions of methane into the atmosphere and thus play an important role for the global cycle of this greenhouse gas.However,gas released from natural hydrocarbon seeps are not pure methane but commonly mixed hydrocarbons.Currently,how methanotrophic bacteria behave in the co-presence of methane and heavier hydrocarbons remains unknown.In this paper,the bacteria were cultured aerobically in fresh sediment samples(collected from Bohai Bay in eastern China)at 28℃under the atmospheres of pure methane and methane+ethane+propane mixed gas,respec-tively.The prevailing terrigenous n-alkanes and fatty acids in the original sediment samples varied consistently after incubations,confirming the proceeding of aerobic bacterial activities.The real-time quantitative PCR assay and sequencing of the 16S rRNA and particulate methane monooxygenase(pmoA)genes revealed the changes of microbe communities to a methanotroph-dominating structure after incubations.Particularly,after incubations the family Methylococcaceae(typeⅠmethanotrophs)became dominant with proportions higher than 40%,whereas Methylocystaceae(typeⅡmethanotrophs)nearly disappeared in all incubated samples.More-over,the species of methanotrophs from the samples treated with pure methane were dominated by Methylobacter luteus,whereas Methylobacter whittenburyi took the predominant proportion in the samples treated with mixed gas.The phenomenon suggests that some methanotrophs may also utilize ethane and propane.Collectively,this study may help to gain a better understanding of the ef-fects and contributions of microbial activities in marine hydrocarbon seep ecosystems.
文摘Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional external heating. This phenomenon is important in the development of catalytic combustion and catalytic partial oxidation processes, both of which have received extensive attention in recent years. In addition, catalytic ignition studies provide experimental data which can be used to test theoretical hydrocarbon oxidation models. For these reasons, catalytic ignition has been frequently studied. This review summarizes the experimental methods used to study catalytic ignition of light hydrocarbons and describes the experimental and theoretical results obtained related to catalytic ignition. The role of catalyst metal, fuel and fuel concentration, and catalyst state in catalytic ignition are examined, and some conclusions are drawn on the mechanism of catalytic ignition.
文摘Metalloporphyrins immobilized into NaY zeolite are described as catalysts for hydrocarbon oxyfuntionalization. Manganese(III) and iron(III)tetrakis(4-N-methylpyridyl)-porphyrin (MnP1 and FeP1), and manganese(III) and iron(III) tetrakis(4-N-benzylpiridil)-porphyrin (MnP2 and FeP2) were impregnated (MnP1-NaYimp, FeP1-NaYimp, MnP2-NaYimp, FeP2-NaYimp, respectively) and encapsulated (MnP1-NaY, FeP1-NaY, MnP2-NaY and FeP2-NaY) into the NaY zeolite. These catalysts were used in the oxidation of (Z)-cyclooctene, cyclohexane, and adamantane by iodosylbezene (PhIO). These systems were able to epoxidize (Z)-cyclooctene with cis-epoxycyclooctane yields as high as 100%. By using cyclohexane and adamantane as substrate, the susceptibility of the benzyl groups on the porphyrin ring of the MnP materials, led to a different distribution of the oxidized products. With FePs, this susceptibility was not detected because the species responsible for the oxidations, FeIV(O)P·+, is more active than MnV(O)P. In conclusion, cationic metalloporphyrins immobilized into NaX zeolites, are good cytochrome P-450 models is less polar solvents since the selectivity of the system indicates the “in cage” solvent oxygen rebound oxidative process.
基金Supported by National Natural Science Foundation of China(Grant Nos.51335005,51321092)National Key Basic Research Program of China(973 Program,Grant No.2013CB934200)the Foundation for the Supervisor of Beijing Excellent Doctoral Dissertation(Grant No.20111000305)
文摘The performance of a lubricant largely depends on the additives it involves. However, currently used additives cause severe pollution if they are burned and exhausted. Therefore, it is necessary to develop a new generation of green additives. Graphene oxide(GO) consists of only C, H and O and thus is considered to be environmentally friendly. So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically. It is found that, with the addition of GO sheets, both the coefficient of friction(COF) and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction. Moreover, GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%. After rubbing, GO is detected on the wear scars through Raman spectroscopy. And it is believed that, during the rubbing, GO sheets adhere to the sliding surfaces, behaving like protective films and preventing the sliding surfaces from contacting with each other directly. This paper proves that the GO sheet is an effective lubricant additive, illuminates the lubrication mechanism, and provides some critical parameters for the practical application of GO sheets in lubrication.
基金financially supported by the National Key R&D Program of China(Grant No.2017YFC0603105)。
文摘Following consideration of the characteristics of high temperature,high pressure and high in-situ stress in ultradeep sedimentary basins,together with the existence of hydrocarbon phase state transformation,hydrocarbon-water-rock interaction and rock mechanical property transition at those depths,the evaluation index system for hydrocarbon preservation was established.The physical leakage evaluation indexes can be divided into three categories:the dynamic efficiency indexes of micro-sealing,caprock integrity and natural gas diffusion.The chemical loss evaluation indexes can be divided into two categories:the thermochemical sulfate reduction(TSR)index in marine gypsum-bearing carbonate strata and the thermochemical oxidation of hydrocarbons(TOH)index in clastic strata.The slippage angle and overconsolidation ratio(OCR)are the key evaluation indexes in the evaluation of the integrity of shale caprocks.TSR intensity can be quantitatively calculated by use of the Zn PVT state parameter method.The TOH strength can be used to estimate the degree of hydrocarbon chemical loss,based on the TOH-related authigenic calcite cement content or the degree of negativeδ^(13)C of authigenic calcite.For the evaluation of ultra-deep preservation in specific areas,key indexes can be selected according to the local geological conditions,instead of all indexes needing to be evaluated for every scenario.
文摘Hybrid organic-inorganic silica materials containing organic functional groups have been preparedby the reaction of activated silica with a silane coupling reagent such as N-(2-aminoethyl)3-aminopropyltrimethoxysilane. The hybrid silica was further modified by organic compounds having abifunctional group. These modified hybrid silicas were used as catalysts for various nucleophilic reactions.And also, these were complexed with metallic ions for use as catalysts for oxygen oxidation of hydrocarbons.
文摘In this study,graphene oxide was covalently immobilized on silica-coated magnetite and then modified with 2-phenylethylamine to give a nanocomposite of type Fe3O4@SiO2@GO-PEA that can be applied to the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons(PAHs) from water samples.The resulting microspheres(Fe3O4@SiO2@GO-PEA) were characterized by Fourier transform-infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),CHNS elemental analysis,and vibrating sample magnetometry(VSM) techniques.The adsorbent possesses the magnetic properties of Fe3O4 nanoparticles that allow them easily to be separated by an external magnetic field.They also have the high specific surface area of graphene oxide which improves adsorption capacity.Desorption conditions,extraction time,amount of adsorbent,salt concentration,and pH were investigated and optimized.Following desorption,the PAHs were quantified by gas chromatography with flame ionization detection(GC-FID).The limits of detection(at an S/N ratio of 3) were achieved from 0.005 to0.1 μg/L with regression coefficients(R2) higher than 0.9954.The relative standard deviations(RSDs) were below 5.8%(intraday) and 6.2%(inter-day),respectively.The method was successfully applied to the analysis of PAHs in environmental water samples where it showed recoveries in the range between 71.7%and 106.7%(with RSDs of 1.6%to 8.4%,for n = 3).The results indicated that the Fe3O4@SiO2@GO-PEA microspheres had a great promise to extraction of PAHs from different water samples.
基金This work was supported by the China Postdoctoral Science Foundation(No.2020M670355)the National Key R&D Program of China(No.2018YFA0702003)+2 种基金the National Natural Science Foundation of China(Nos.21890383,21671117,and 21871159)the Science and Technology Key Project of Guangdong Province of China(No.2020B010188002)Beijing Municipal Science&Technology Commission(No.Z191100007219003).
文摘In recent decades,the environmental protection and long-term sustainability have become the focus of attention due to the increasing pollution generated by the intense industrialization.To overcome these issues,environmental catalysis has increasingly been used to solve the negative impact of pollutants emission on the global environment and human health.Supported platinum-metal-group(PGM)materials are commonly utilized as the state-of-the-art catalysts to eliminate gaseous pollutants but large quantities of PGMs are required.By comparison,single-atom site catalysts(SACs)have attracted much attention in catalysis owing to their 100%atom efficiency and unique catalytic performances towards various reactions.Over the past decade,we have witnessed burgeoning interests of SACs in heterogeneous catalysis.However,to the best of our knowledge,the systematic summary and analysis of SACs in catalytic elimination of environmental pollutants has not yet been reported.In this paper,we summarize and discuss the environmental catalysis applications of SACs.Particular focus was paid to automotive and stationary emission control,including model reaction(CO oxidation,NO reduction and hydrocarbon oxidation),overall reaction(three-way catalytic and diesel oxidation reaction),elimination of volatile organic compounds(formaldehyde,benzene,and toluene),and removal/decomposition of other pollutants(Hg0 and SO3).Perspectives related to further challenges,directions and design strategies of single-atom site catalysts in environmental catalysis were also provided.
基金supported by the Natural Sciences Foundation of China(Nos.91544232&51408015)the Ministry of Environmental Protection Special Funds for Scientific Research on Public Causes(No.201409006)+4 种基金the Beijing municipal science and technology plan projects(No.Z131100001113029)the 13th graduate students of science and technology fund of Beijing University of Technology(ykj-2014-11484)the projects supported by Beijing Municipal Commission of Science and Technology(No.Z141100001014002)Beijing Municipal Commission of Education(No.PXM2016_014204_001029)National Science and Technology Support Project of China(No.2014BAC23B02)
文摘A total of 15 light-duty diesel vehicles(LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons(HC) and nitrogen oxides(NOx) at different speeds, chemical species profiles and ozone formation potential(OFP) of volatile organic compounds(VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOxhad been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOxemissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%–45.2%, followed by aromatics and alkenes. The most abundant species were propene,ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity(MIR)method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%–91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene.