In-depth knowledge of the microbes responsible for biogenic amine(BA)production during soy sauce fermentation remains limited.Herein,the variations in the BA profiles,microbial communities,and microbes involved in BA ...In-depth knowledge of the microbes responsible for biogenic amine(BA)production during soy sauce fermentation remains limited.Herein,the variations in the BA profiles,microbial communities,and microbes involved in BA production during the fermentation of soy sauce through Japanese-type(JP)and Cantonese-type(CP)processes were compared.BA analysis revealed that the most abundant BA species were putrescine,tyramine,and histamine in the later three stages(1187.68,785.16,and 193.20 mg/kg on average,respectively).The BA profiles differed significantly,with CP samples containing higher contents of putrescine,tyramine,and histamine(P<0.05)at the end of fermentation.Metagenomic analysis indicated that BA-producing genes exhibited different abundance profiles,with most genes,including spe A,spe B,arg,spe E,and tyr DC,having higher abundances in microbial communities during the CP process.In total,15 high-quality metagenome-assembled genomes(MAGs)were retrieved,of which 10 encoded at BA production-related genes.Enterococcus faecium(MAG10)and Weissella paramesenteroides(MAG5)might be the major tyramine producers.The high putrescine content in CP might be associated with the high abundance of Staphylococcus gallinarum(MAG8).This study provides a comprehensive understanding of the diversity and abundance of genes involved in BA synthesis,especially at the species level,during food fermentation.展开更多
Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from t...Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.展开更多
To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community a...To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate.展开更多
Lactic acid bacteria and coagulase-negative staphylococci play an important role in the production of fermented sausages,such as inhibiting the growth of undesirable bacteria and antioxidant.In this study,the effects ...Lactic acid bacteria and coagulase-negative staphylococci play an important role in the production of fermented sausages,such as inhibiting the growth of undesirable bacteria and antioxidant.In this study,the effects of inoculation with different starter cultures(Lactiplantibacillus plantarum HN108 and Staphylococcus simulans NJ209)on the free amino acids(FAAs),biogenic amines(BAs)and volatile compounds of fermented sausages were investigated using an amino acid analyzer,ultra performance liquid chromatography and gas chromatography-ion mobility spectrometry,respectively.The pH and carbonyl content of the inoculated group was significantly lower than those in the control group(P<0.05).L.plantarum HN108 significantly reduced the content of FAAs and BAs in fermented sausage production(P<0.05),while S.simulans NJ209 promoted the formation of FAAs(especially bitter amino acids)and exhibited slight BAs-reducing activity.In addition,L.plantarum HN108 promoted the formation of volatile compounds such as ketones,alcohols and alkenes in sausages.In conclusion,L.plantarum HN108 could contribute to reducing the content of putrescine and tyramine and forming the desirable flavor compounds in fermented sausages.Thus,L.plantarum HN108 is expected to be a starter culture that can improve the safety and flavor of fermented sausages.展开更多
Organic-inorganic MoO_(3)/PI(MoPI)composites were prepared using a simple one-pot thermal copolymerization method.The resulting composites exhibited enhanced photocatalytic activity for the selective oxidation of benz...Organic-inorganic MoO_(3)/PI(MoPI)composites were prepared using a simple one-pot thermal copolymerization method.The resulting composites exhibited enhanced photocatalytic activity for the selective oxidation of benzylamine to N-benzylidene benzylamine(N-BDBA)in ambient air under simulated solar light irradiation compared to pristine MoO_(3) or polyimide(PI).In particular,the MoPI composite with a 0.3:1 molar ratio of Mo to melamine,referred to as MoPI-0.3,demonstrated the best performance in the photo-oxidation of benzylamine,achieving a benzylamine conversion of 95%with a N-BDBA selectivity exceeding 99%after 3 h irradiation.The enhanced photocatalytic activity of the MoPI-0.3 catalyst was attributed to the formation of a direct Z-scheme heterojunction between MoO_(3) and PI,facilitating more efficient separation of the photoinduced electrons and holes.Additionally,the MoPI-0.3 composite maintained considerably high activity over four consecutive cycles,highlighting its good stability and recyclability.Furthermore,the MoPI-0.3 composite could photo-oxidize benzylamine derivatives and heterocyclic amines to their corresponding imines,demonstrating the universal applicability of this composite catalyst.展开更多
Rechargeable magnesium(Mg)-metal batteries have brought great expect to overcome the safety and energy density concerns of typical lithium-ion batteries.However,interracial passivation of the Mgmetal anode impairs the...Rechargeable magnesium(Mg)-metal batteries have brought great expect to overcome the safety and energy density concerns of typical lithium-ion batteries.However,interracial passivation of the Mgmetal anode impairs the reversible Mg plating/stripping chemistries,resulting in low Coulombic efficiency and large overpotential.In this work,a facile isobutylamine(IBA)-assisted activation strategy has been proposed and the fundamental mechanism has been unveiled in a specific way of evolving active species and forming MgH_(2)-based solid-electrolyte interphase.After introducing IBA into a typical electrolyte of magnesium bis(trifluoromethanesulfo nyl) imide(Mg(TFSI)_(2)) in diglyme(G2) solvents,electrolyte species of [Mg^(2+)(IBA)5]^(2+) and protonated amine-based cations of [(IBA)H]^(+) have been detected by nuclear magnetic resonance and mass spectra.This not only indicates direct solvation of IBA toward Mg^(2+)but also suggests its ionization,which is central to mitigating the decomposition of G2 and TFSI anions by forming neutrally charged [(IBAH^(+))(TFSI^(-))]~0 and other complex ions.A series of experiments,including cryogenic-electron microscopy,D_(2)O titration-mass spectra,and time of flight secondary ion mass spectrometry results,reveal a thin,non-passivated,and MgH_(2)-containing interphase on the Mg-metal anode.Besides,uniform and dendrite-free Mg electrodeposits have been revealed in composite electrolytes.Benefiting from the activation effects of IBA,the composite electrolyte displays superior electrochemical performance(overpotential is approximately 0.16 V versus 2.00 V for conventional electrolyte;Coulombic efficiency is above 90% versus <10% for conventional electrolyte).This work offers a fresh direction to advanced electrolyte design for next-generation rechargeable batteries.展开更多
Nano-TATB was developed in microchannels by physical method and chemical method,respectively.The effects of total flow rate,number of microreactor plates,solvent/non-solvent ratio and temperature on the particle size ...Nano-TATB was developed in microchannels by physical method and chemical method,respectively.The effects of total flow rate,number of microreactor plates,solvent/non-solvent ratio and temperature on the particle size of TATB in the physical method were studied.Prepared TATB were characterized by Nano Sizer,Scanning Electron Microscopy,Specific surface aperture analyzer,X-ray diffraction,Fourier transform infrared spectroscopy and Differential Scanning Calorimetry.The results show that the TATB obtained by physical method and chemical method are spherical,with average particle size of 130.66 nm and 108.51 nm,respectively.Specific surface areas of TATB obtained by physical and chemical methods are 21.37 m^(2)/g and 21.91 m^(2)/g,respectively.Compared with the specific surface area of micro-TATB(0.0808 m^(2)/g),the specific surface area of nano-TATB is significantly increased.DSC test results show that the smaller the particle size of TATB,the lower the thermal decomposition temperature.In addition,by simulating the mixing state of fluid in microchannels and combining with the classical nucleation theory,the mechanism of preparing nano-TATB by microchannels was proposed.展开更多
A new type of composite adsorbents was synthesized by incorporating monoethanol amine （MEA） into β-zeolite. The parent and MEA- functionalized β-zeolites were characterized by X-ray diffraction （XRD）, N2 adsorpt...A new type of composite adsorbents was synthesized by incorporating monoethanol amine （MEA） into β-zeolite. The parent and MEA- functionalized β-zeolites were characterized by X-ray diffraction （XRD）, N2 adsorption, and thermogravimetric analysis （TGA）. The adsorption behavior of carbon dioxide （CO2）, methane （CH4）, and nitrogen （N2） on these adsorbents was investigated at 303 K. The results show that the structure of zeolite was well preserved after MEA modification. In comparison with CH4 and N2, CO2 was preferentially adsorbed on the adsorbents investigated. The introduction of MEA significantly improved the selectivity of both CO2/CH4 and CO2/N2, the optimal selectivity of CO2/CH4 can reach 7.70 on 40 wt% of MEA-functionalized β-zeolite （MEA（40）-β） at 1 atm. It is worth noticing that a very high selectivity of CO2/N2 of 25.67 was obtained on MEA（40）-β. Steric effect and chemical adsorbate-adsorbent interaction were responsible for such high adsorption selectivity of CO2. The present MEA-functionalized β-zeolite adsorbents may be a good candidate for applications in flue gas separation, as well as natural gas and landfill gas purifications.展开更多
Myriad evidence attests to the health-promoting benefits of tea drinking.While there are multiple factors of tea influencing the effective biological properties,tea polyphenols are the most significant and valuable co...Myriad evidence attests to the health-promoting benefits of tea drinking.While there are multiple factors of tea influencing the effective biological properties,tea polyphenols are the most significant and valuable components.The chemical characterization and physical characteristics of tea polyphenols have been comprehensively studied over the previous years.Still the emergence of new chemistry in tea,particularly the property of scavenging reactive carbonyl species(RCS)and the newly discovered flavoalkaloid compounds,has drawn increasing attention.In this review,we summarize recent findings of a new class of compounds in tea-flavonoid alkaloids(flavoalkaloids),which exist in fresh tea leaves and can be generated during the process of post-harvesting,and also postulate the formation mechanism of flavoalkaloids between catechins and theanine-derived Strecker aldehyde.Additionally,we detail the up-to-date research results of tea polyphenols regarding their ability to trap RCS and their in vivo aminated metabolites to suppress advanced glycation ends products(AGEs).We further raise questions to be addressed in the near future,including the synthetic pathways for the generation of flavoalkaloids and AGEs in fresh tea leaves before processing and the concentrations of tea polyphenols that affect their RCS scavenging capability due to their pro-oxidant nature.More intensive research is warranted to elucidate the mechanisms of action underlying the biological activity of flavoalkaloids and the pharmacological application of tea polyphenols in scavenging RCS and impeding detrimental AGEs.展开更多
Gas flooding such as CO2 flooding may be effectively applied to ultra-low permeability reservoirs, but gas channeling is inevitable due to low viscosity and high mobility of gas and formation heterogeneity. In order t...Gas flooding such as CO2 flooding may be effectively applied to ultra-low permeability reservoirs, but gas channeling is inevitable due to low viscosity and high mobility of gas and formation heterogeneity. In order to mitigate or prevent gas channeling, ethylenediamine is chosen for permeability profile control. The reaction mechanism of ethylenediamine with CO2, injection performance, swept volume, and enhanced oil recovery were systematically evaluated. The reaction product of ethylenediamine and CO2 was a white solid or a light yellow viscous liquid, which would mitigate or prevent gas channeling. Also, ethylenediamine could be easily injected into ultra-low permeability cores at high temperature with protective ethanol slugs. The core was swept by injection of 0.3 PV ethylenediamine. Oil displacement tests performed on heterogeneous models with closed fractures, oil recovery was significantly enhanced with injection of ethylenediamine. Experimental results showed that using ethylenediamine to plug high permeability layers would provide a new research idea for the gas injection in fractured, heterogeneous and ultra-low permeability reservoirs. This technology has the potential to be widely applied in oilfields.展开更多
Amine-silica composite materials for post-combustion COcapture have attracted considerable attention because of their high COuptake at low COconcentrations, excellent COcapture selectivity in the presence of moisture,...Amine-silica composite materials for post-combustion COcapture have attracted considerable attention because of their high COuptake at low COconcentrations, excellent COcapture selectivity in the presence of moisture, and lower energy requirements for sorbent regeneration. This review discusses the recent advances in amine-silica composites for COcapture, including adsorbent preparation and characterization, COcapture under dry and moisture conditions at different COpartial pressures, sorbent regeneration, and stability after many cyclic sorption-desorption runs.展开更多
This manuscript is reviewing the presence of substances of safety concern that may be generated in different types of meat products.Such substances include N-nitrosamines that can be generated under certain conditions...This manuscript is reviewing the presence of substances of safety concern that may be generated in different types of meat products.Such substances include N-nitrosamines that can be generated under certain conditions when using nitrite as preservative,the polycyclic aromatic hydrocarbons generated as a consequence of particular smoking processes,heterocyclic aromatic amines generated under particular cooking conditions,compounds released from the oxidation of lipids and proteins,Maillard reaction products like acrylamide and carboxymethyl lysine,and amines that can be generated and accumulated in fermented meats.These hazardous compounds,their mechanisms of generation,risks for health and ways of preventing its presence in meat products are briefly described in this review.展开更多
Wormlike/lamellar microporous carbons were prepared by using long alkyl chain primary amine hydrochloride as the template and resorci- nol/formaldehyde as the carbon source under highly acidic conditions. The template...Wormlike/lamellar microporous carbons were prepared by using long alkyl chain primary amine hydrochloride as the template and resorci- nol/formaldehyde as the carbon source under highly acidic conditions. The template can be eliminated by high temperature treatment under an inert atmosphere. The obtained carbon materials were characterized by N2 adsorption-desorption, transmission electron microscopy, ther- mogravimetry and scanning electron microscopy. The results show that dodecylamine hydrochloride surfactant can be used as the template of wormlike micropores structure while octadecylamine hydrochloride results in both lamellar and wormlike micropores. The obtained carbon materials have the similar pore size in the range of 0.5-0.59 nm, but with various morphologies such as monolith, spheres, and coralline. The microporous carbon obtained from dodecylamine hydrochloride surfactant shows good adsorption performance to remove the refractory sulfur compounds and nitrogen-containing compounds in fuel.展开更多
In industrial amine plants the optimized operating conditions are obtained from the conclusion of occurred events and challenges that are normal in the working units. For the sake of reducing the costs, time consuming...In industrial amine plants the optimized operating conditions are obtained from the conclusion of occurred events and challenges that are normal in the working units. For the sake of reducing the costs, time consuming, and preventing unsuitable accidents, the optimization could be performed by a computer program. In this paper, simulation and parameter analysis of amine plant is performed at first. The optimization of this unit is studied using Non-Dominated Sorting Genetic Algorithm-II in order to produce sweet gas with CO 2 mole percentage less than 2.0% and H 2 S concentration less than 10 ppm for application in Fischer-Tropsch synthesis. The simulation of the plant in HYSYS v.3.1 software has been linked with MATLAB code for real-parameter NSGA-II to simulate and optimize the amine process. Three scenarios are selected to cover the effect of （DEA/MDEA） mass composition percent ratio at amine solution on objective functions. Results show that sour gas temperature and pressure of 33.98 ？ C and 14.96 bar, DEA/CO 2 molar flow ratio of 12.58, regeneration gas temperature and pressure of 94.92 ？ C and 3.0 bar, regenerator pressure of 1.53 bar, and ratio of DEA/MDEA = 20%/10% are the best values for minimizing plant energy consumption, amine circulation rate, and carbon dioxide recovery.展开更多
A pH predictive model based on acid–base equilibria and ion equilibria was proposed to calculate the pH value of the overhead condensing system of crude distillation unit. The pH model could be used to predict the ap...A pH predictive model based on acid–base equilibria and ion equilibria was proposed to calculate the pH value of the overhead condensing system of crude distillation unit. The pH model could be used to predict the appropriate amounts of neutralizers by measuring the Cl-ion concentration of the overhead knockout drum. The pH values of various neutralized streams were estimated by this model. The results showed that the predicted pH values were in good agreement with the experimental ones. The trend of the corrosion inhibition efficiency decreases in the following order: ethylenediamine > N,Ndimethylethanolamine> triethylamine > 3-methoxypropylamine > morpholine. The difficulty in the accurate control of corrosion was solved, and a good instruction was provided for mitigating corrosion in refinery.展开更多
The flotation of diaspore and kaolinite by one of a series of tertiary amines（DRN,DEN,DPN and DBN） was investigated.The tertiary amines show better floating recovery for kaolinite compared to diaspore.The maximum re...The flotation of diaspore and kaolinite by one of a series of tertiary amines（DRN,DEN,DPN and DBN） was investigated.The tertiary amines show better floating recovery for kaolinite compared to diaspore.The maximum recovery D-value is 45%over a pH range from 3 to 8.FT-IR spectra confirm the presence of hydroxyl groups on the surface of kaolinite and diaspore.Zeta potential measurements show that the mineral surfaces are negatively charged over a wide pH range.Ionization of hydroxyl groups mainly accounts for the surface charging mechanism.The adsorption of tertiary amines onto the mineral surface is due mainly to electrostatic effects and the difference in electrostatic effect between a collector and the two minerals can explain the flotation separation.Inductive electronic and steric effects from the substituent groups result in different collecting powers for the four tertiary amines.展开更多
Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reaction...Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.展开更多
Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by...Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.展开更多
基金supported by the Natural Science Foundation of Guangdong Province(2022A1515012158)the National Science Foundation of China(41977138)+3 种基金the Construction Project of Teaching Quality and Teaching Reform in Guangdong Province(SJD202001)the General University Project of Guangdong Provincial Department of Education(2021KCXTD070 and 2021ZDZX4072)the Key Project of Social Welfare and Basic Research of Zhongshan City(2020B2010)the Start-up Fund from the Zhongshan Institute at the University of Electronic Science and Technology in China(419YKQN12)。
文摘In-depth knowledge of the microbes responsible for biogenic amine(BA)production during soy sauce fermentation remains limited.Herein,the variations in the BA profiles,microbial communities,and microbes involved in BA production during the fermentation of soy sauce through Japanese-type(JP)and Cantonese-type(CP)processes were compared.BA analysis revealed that the most abundant BA species were putrescine,tyramine,and histamine in the later three stages(1187.68,785.16,and 193.20 mg/kg on average,respectively).The BA profiles differed significantly,with CP samples containing higher contents of putrescine,tyramine,and histamine(P<0.05)at the end of fermentation.Metagenomic analysis indicated that BA-producing genes exhibited different abundance profiles,with most genes,including spe A,spe B,arg,spe E,and tyr DC,having higher abundances in microbial communities during the CP process.In total,15 high-quality metagenome-assembled genomes(MAGs)were retrieved,of which 10 encoded at BA production-related genes.Enterococcus faecium(MAG10)and Weissella paramesenteroides(MAG5)might be the major tyramine producers.The high putrescine content in CP might be associated with the high abundance of Staphylococcus gallinarum(MAG8).This study provides a comprehensive understanding of the diversity and abundance of genes involved in BA synthesis,especially at the species level,during food fermentation.
基金supported by the Shanghai Agricultural Science and Technology Program (2022-02-08-00-12-F01176)he National Natural Science Foundation of China (52006135)
文摘Direct air capture(DAC)of CO_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission technologies.Since large air flows are required to capture the ultradilute CO_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC systems.In this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-CO_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMOs)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent loadings.The printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMO monoliths.This structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMO powder into a monolith.After impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a CO_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC adsorbents.Smearing of the amino-polymers during the post-printing process affects the diffusion of CO_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation monoliths.The optimal PEI/MeOH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.
基金supported by National Natural Science Foundation of China(32022066,32101975)Zhejiang Province Natural Science Foundation(LQ22C200017)+1 种基金China Postdoctoral Foundation(2020M681806,2021T140348)Science and Technology Programs of Ningbo(202003N4130,202002N3067)。
文摘To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institution(PAPD).
文摘Lactic acid bacteria and coagulase-negative staphylococci play an important role in the production of fermented sausages,such as inhibiting the growth of undesirable bacteria and antioxidant.In this study,the effects of inoculation with different starter cultures(Lactiplantibacillus plantarum HN108 and Staphylococcus simulans NJ209)on the free amino acids(FAAs),biogenic amines(BAs)and volatile compounds of fermented sausages were investigated using an amino acid analyzer,ultra performance liquid chromatography and gas chromatography-ion mobility spectrometry,respectively.The pH and carbonyl content of the inoculated group was significantly lower than those in the control group(P<0.05).L.plantarum HN108 significantly reduced the content of FAAs and BAs in fermented sausage production(P<0.05),while S.simulans NJ209 promoted the formation of FAAs(especially bitter amino acids)and exhibited slight BAs-reducing activity.In addition,L.plantarum HN108 promoted the formation of volatile compounds such as ketones,alcohols and alkenes in sausages.In conclusion,L.plantarum HN108 could contribute to reducing the content of putrescine and tyramine and forming the desirable flavor compounds in fermented sausages.Thus,L.plantarum HN108 is expected to be a starter culture that can improve the safety and flavor of fermented sausages.
基金supported by the Opening Project of Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan (LZJ2101)the Fundamental Research Funds of China West Normal University (19D038)
文摘Organic-inorganic MoO_(3)/PI(MoPI)composites were prepared using a simple one-pot thermal copolymerization method.The resulting composites exhibited enhanced photocatalytic activity for the selective oxidation of benzylamine to N-benzylidene benzylamine(N-BDBA)in ambient air under simulated solar light irradiation compared to pristine MoO_(3) or polyimide(PI).In particular,the MoPI composite with a 0.3:1 molar ratio of Mo to melamine,referred to as MoPI-0.3,demonstrated the best performance in the photo-oxidation of benzylamine,achieving a benzylamine conversion of 95%with a N-BDBA selectivity exceeding 99%after 3 h irradiation.The enhanced photocatalytic activity of the MoPI-0.3 catalyst was attributed to the formation of a direct Z-scheme heterojunction between MoO_(3) and PI,facilitating more efficient separation of the photoinduced electrons and holes.Additionally,the MoPI-0.3 composite maintained considerably high activity over four consecutive cycles,highlighting its good stability and recyclability.Furthermore,the MoPI-0.3 composite could photo-oxidize benzylamine derivatives and heterocyclic amines to their corresponding imines,demonstrating the universal applicability of this composite catalyst.
基金National Natural Science Foundation of China (22279068, 51972187)Natural Science Foundation of Shandong Province (ZR2021QE166)Qingdao New Energy Shandong Laboratory Open Project (QNESL OP202312)。
文摘Rechargeable magnesium(Mg)-metal batteries have brought great expect to overcome the safety and energy density concerns of typical lithium-ion batteries.However,interracial passivation of the Mgmetal anode impairs the reversible Mg plating/stripping chemistries,resulting in low Coulombic efficiency and large overpotential.In this work,a facile isobutylamine(IBA)-assisted activation strategy has been proposed and the fundamental mechanism has been unveiled in a specific way of evolving active species and forming MgH_(2)-based solid-electrolyte interphase.After introducing IBA into a typical electrolyte of magnesium bis(trifluoromethanesulfo nyl) imide(Mg(TFSI)_(2)) in diglyme(G2) solvents,electrolyte species of [Mg^(2+)(IBA)5]^(2+) and protonated amine-based cations of [(IBA)H]^(+) have been detected by nuclear magnetic resonance and mass spectra.This not only indicates direct solvation of IBA toward Mg^(2+)but also suggests its ionization,which is central to mitigating the decomposition of G2 and TFSI anions by forming neutrally charged [(IBAH^(+))(TFSI^(-))]~0 and other complex ions.A series of experiments,including cryogenic-electron microscopy,D_(2)O titration-mass spectra,and time of flight secondary ion mass spectrometry results,reveal a thin,non-passivated,and MgH_(2)-containing interphase on the Mg-metal anode.Besides,uniform and dendrite-free Mg electrodeposits have been revealed in composite electrolytes.Benefiting from the activation effects of IBA,the composite electrolyte displays superior electrochemical performance(overpotential is approximately 0.16 V versus 2.00 V for conventional electrolyte;Coulombic efficiency is above 90% versus <10% for conventional electrolyte).This work offers a fresh direction to advanced electrolyte design for next-generation rechargeable batteries.
基金National Natural Science Foundation of China(No.21875109)to provide fund for conducting experiments.
文摘Nano-TATB was developed in microchannels by physical method and chemical method,respectively.The effects of total flow rate,number of microreactor plates,solvent/non-solvent ratio and temperature on the particle size of TATB in the physical method were studied.Prepared TATB were characterized by Nano Sizer,Scanning Electron Microscopy,Specific surface aperture analyzer,X-ray diffraction,Fourier transform infrared spectroscopy and Differential Scanning Calorimetry.The results show that the TATB obtained by physical method and chemical method are spherical,with average particle size of 130.66 nm and 108.51 nm,respectively.Specific surface areas of TATB obtained by physical and chemical methods are 21.37 m^(2)/g and 21.91 m^(2)/g,respectively.Compared with the specific surface area of micro-TATB(0.0808 m^(2)/g),the specific surface area of nano-TATB is significantly increased.DSC test results show that the smaller the particle size of TATB,the lower the thermal decomposition temperature.In addition,by simulating the mixing state of fluid in microchannels and combining with the classical nucleation theory,the mechanism of preparing nano-TATB by microchannels was proposed.
基金supported by the Major Basic Research Project of Natural Science Foundation of Jiangsu Province Colleges (No. 08 kJA530001)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0732)
文摘A new type of composite adsorbents was synthesized by incorporating monoethanol amine （MEA） into β-zeolite. The parent and MEA- functionalized β-zeolites were characterized by X-ray diffraction （XRD）, N2 adsorption, and thermogravimetric analysis （TGA）. The adsorption behavior of carbon dioxide （CO2）, methane （CH4）, and nitrogen （N2） on these adsorbents was investigated at 303 K. The results show that the structure of zeolite was well preserved after MEA modification. In comparison with CH4 and N2, CO2 was preferentially adsorbed on the adsorbents investigated. The introduction of MEA significantly improved the selectivity of both CO2/CH4 and CO2/N2, the optimal selectivity of CO2/CH4 can reach 7.70 on 40 wt% of MEA-functionalized β-zeolite （MEA（40）-β） at 1 atm. It is worth noticing that a very high selectivity of CO2/N2 of 25.67 was obtained on MEA（40）-β. Steric effect and chemical adsorbate-adsorbent interaction were responsible for such high adsorption selectivity of CO2. The present MEA-functionalized β-zeolite adsorbents may be a good candidate for applications in flue gas separation, as well as natural gas and landfill gas purifications.
基金supported by Hubei Science and Technology Plan Key Project(G2019ABA100)。
文摘Myriad evidence attests to the health-promoting benefits of tea drinking.While there are multiple factors of tea influencing the effective biological properties,tea polyphenols are the most significant and valuable components.The chemical characterization and physical characteristics of tea polyphenols have been comprehensively studied over the previous years.Still the emergence of new chemistry in tea,particularly the property of scavenging reactive carbonyl species(RCS)and the newly discovered flavoalkaloid compounds,has drawn increasing attention.In this review,we summarize recent findings of a new class of compounds in tea-flavonoid alkaloids(flavoalkaloids),which exist in fresh tea leaves and can be generated during the process of post-harvesting,and also postulate the formation mechanism of flavoalkaloids between catechins and theanine-derived Strecker aldehyde.Additionally,we detail the up-to-date research results of tea polyphenols regarding their ability to trap RCS and their in vivo aminated metabolites to suppress advanced glycation ends products(AGEs).We further raise questions to be addressed in the near future,including the synthetic pathways for the generation of flavoalkaloids and AGEs in fresh tea leaves before processing and the concentrations of tea polyphenols that affect their RCS scavenging capability due to their pro-oxidant nature.More intensive research is warranted to elucidate the mechanisms of action underlying the biological activity of flavoalkaloids and the pharmacological application of tea polyphenols in scavenging RCS and impeding detrimental AGEs.
基金Financial support for this work from National Sciencetechnology Support Plan Projects (No. 2012BAC26B00)the Science Foundation of China University of Petroleum, Beijing (No.2462012KYJJ23)
文摘Gas flooding such as CO2 flooding may be effectively applied to ultra-low permeability reservoirs, but gas channeling is inevitable due to low viscosity and high mobility of gas and formation heterogeneity. In order to mitigate or prevent gas channeling, ethylenediamine is chosen for permeability profile control. The reaction mechanism of ethylenediamine with CO2, injection performance, swept volume, and enhanced oil recovery were systematically evaluated. The reaction product of ethylenediamine and CO2 was a white solid or a light yellow viscous liquid, which would mitigate or prevent gas channeling. Also, ethylenediamine could be easily injected into ultra-low permeability cores at high temperature with protective ethanol slugs. The core was swept by injection of 0.3 PV ethylenediamine. Oil displacement tests performed on heterogeneous models with closed fractures, oil recovery was significantly enhanced with injection of ethylenediamine. Experimental results showed that using ethylenediamine to plug high permeability layers would provide a new research idea for the gas injection in fractured, heterogeneous and ultra-low permeability reservoirs. This technology has the potential to be widely applied in oilfields.
基金supported financially by the National Natural Science Foundation of China (No. 21607121)by the National Research Foundation of Korea (NRF) (Grant number: NRF2015R1A4A1042434)
文摘Amine-silica composite materials for post-combustion COcapture have attracted considerable attention because of their high COuptake at low COconcentrations, excellent COcapture selectivity in the presence of moisture, and lower energy requirements for sorbent regeneration. This review discusses the recent advances in amine-silica composites for COcapture, including adsorbent preparation and characterization, COcapture under dry and moisture conditions at different COpartial pressures, sorbent regeneration, and stability after many cyclic sorption-desorption runs.
基金Grants AGL2017-89831-R,AGL2015-64673-R and FEDER funds from the Spanish Ministry of Economy,Industry and Competitiveness are acknowledged.Ramon y Cajal postdoctoral contract to LM is also acknowledged。
文摘This manuscript is reviewing the presence of substances of safety concern that may be generated in different types of meat products.Such substances include N-nitrosamines that can be generated under certain conditions when using nitrite as preservative,the polycyclic aromatic hydrocarbons generated as a consequence of particular smoking processes,heterocyclic aromatic amines generated under particular cooking conditions,compounds released from the oxidation of lipids and proteins,Maillard reaction products like acrylamide and carboxymethyl lysine,and amines that can be generated and accumulated in fermented meats.These hazardous compounds,their mechanisms of generation,risks for health and ways of preventing its presence in meat products are briefly described in this review.
基金sponsored by the Foundation for the Author of National Excellent Doctoral Dissertation of PR China (NO.200346)Program for New Century Excellent Talents in University (NCET-04-0270)National Natural Science Foundation of China (NO.20406005)
文摘Wormlike/lamellar microporous carbons were prepared by using long alkyl chain primary amine hydrochloride as the template and resorci- nol/formaldehyde as the carbon source under highly acidic conditions. The template can be eliminated by high temperature treatment under an inert atmosphere. The obtained carbon materials were characterized by N2 adsorption-desorption, transmission electron microscopy, ther- mogravimetry and scanning electron microscopy. The results show that dodecylamine hydrochloride surfactant can be used as the template of wormlike micropores structure while octadecylamine hydrochloride results in both lamellar and wormlike micropores. The obtained carbon materials have the similar pore size in the range of 0.5-0.59 nm, but with various morphologies such as monolith, spheres, and coralline. The microporous carbon obtained from dodecylamine hydrochloride surfactant shows good adsorption performance to remove the refractory sulfur compounds and nitrogen-containing compounds in fuel.
文摘In industrial amine plants the optimized operating conditions are obtained from the conclusion of occurred events and challenges that are normal in the working units. For the sake of reducing the costs, time consuming, and preventing unsuitable accidents, the optimization could be performed by a computer program. In this paper, simulation and parameter analysis of amine plant is performed at first. The optimization of this unit is studied using Non-Dominated Sorting Genetic Algorithm-II in order to produce sweet gas with CO 2 mole percentage less than 2.0% and H 2 S concentration less than 10 ppm for application in Fischer-Tropsch synthesis. The simulation of the plant in HYSYS v.3.1 software has been linked with MATLAB code for real-parameter NSGA-II to simulate and optimize the amine process. Three scenarios are selected to cover the effect of （DEA/MDEA） mass composition percent ratio at amine solution on objective functions. Results show that sour gas temperature and pressure of 33.98 ？ C and 14.96 bar, DEA/CO 2 molar flow ratio of 12.58, regeneration gas temperature and pressure of 94.92 ？ C and 3.0 bar, regenerator pressure of 1.53 bar, and ratio of DEA/MDEA = 20%/10% are the best values for minimizing plant energy consumption, amine circulation rate, and carbon dioxide recovery.
基金supported by the PetroChina Company Limited (20151191)
文摘A pH predictive model based on acid–base equilibria and ion equilibria was proposed to calculate the pH value of the overhead condensing system of crude distillation unit. The pH model could be used to predict the appropriate amounts of neutralizers by measuring the Cl-ion concentration of the overhead knockout drum. The pH values of various neutralized streams were estimated by this model. The results showed that the predicted pH values were in good agreement with the experimental ones. The trend of the corrosion inhibition efficiency decreases in the following order: ethylenediamine > N,Ndimethylethanolamine> triethylamine > 3-methoxypropylamine > morpholine. The difficulty in the accurate control of corrosion was solved, and a good instruction was provided for mitigating corrosion in refinery.
基金supported by the National Key Fundamental Research and Development Program(No.2005CB623701)the National Department Public Benefit Research Foundation from Ministry of Land and Resources(No.201011031 )the Foundation for the Author of Zhengzhou Institute of Multipurpose Utilization of Mineral Resources CAGS(No.2935)
文摘The flotation of diaspore and kaolinite by one of a series of tertiary amines（DRN,DEN,DPN and DBN） was investigated.The tertiary amines show better floating recovery for kaolinite compared to diaspore.The maximum recovery D-value is 45%over a pH range from 3 to 8.FT-IR spectra confirm the presence of hydroxyl groups on the surface of kaolinite and diaspore.Zeta potential measurements show that the mineral surfaces are negatively charged over a wide pH range.Ionization of hydroxyl groups mainly accounts for the surface charging mechanism.The adsorption of tertiary amines onto the mineral surface is due mainly to electrostatic effects and the difference in electrostatic effect between a collector and the two minerals can explain the flotation separation.Inductive electronic and steric effects from the substituent groups result in different collecting powers for the four tertiary amines.
基金financially supported by the National Natural Science Foundation of China(202102007,21978147 and 21935001)the Fundamental Research Funds for the Central Universities(buctrc202112)。
文摘Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.
基金Supported by the Basic Research Program of the State Key Laboratory of Heavy Oil Processing (200310) China University of Petroleum,Beijing,China
文摘Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.
