It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N p...It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N pollution result-ing from excessive N input.Here,we calculate the farmland N budget on the national and regional scales.The N use efficiency(NUE)in China increased by 28.0%during 2005-2018.This improvement is due to the reduction in fertilization and the improvement of crop management.The fragmented farmland is changing to large-scale farmland with the increase in cultivated land area per rural population and the development of agricultural mech-anization.This opportunity brings more possibilities for precision farmland management,thus further improving NUE.The goal of an NUE of 0.6 may be achieved in the 2040s based on the current development trend.This striking N use shift in China has important implications for other developing countries.展开更多
Subcooled liquid solubility is the water solubility for a hypothetical state of liquid. It is an important parameter for multicomponent nonaqueous phase liquids （NAPLs） containing polycyclic aromatic hydrocarbons （...Subcooled liquid solubility is the water solubility for a hypothetical state of liquid. It is an important parameter for multicomponent nonaqueous phase liquids （NAPLs） containing polycyclic aromatic hydrocarbons （PAHs）, which can exist as liquids even though most of the solutes are solid in their pure form at ambient temperature. So far, subcooled liquid solubilities were estimated from the solid water solubility and fugacity ratio of the solid and （subcooled） liquid phase, but rarely derived from experi- mental data. In our study, partitioning batch experiments were performed to determine the subcooled liquid solubility of PAHs in NAPL-water system. For selected PAH, a series of batch experiments were carried out at increased mole fractions of the target component in the NAPL and at a constant NAPL/ water volume ratio. The equilibrium aqueous PAH concentrations were measured with HPLC and/or GC- MS. The suhcooled liquid solubility was derived by extrapolation of the experimental equilibrium aqueous concentration to a mole fraction of unity. With the derived subcooled liquid solubility, the fugacity ratio and enthalpy of fusion of the solute were also estimated. Our results show a good agreement between the experimentally determined and published data.展开更多
It occurs worldwide that the organic components of non-aqueous phase liquid (NAPL) enter the porous medium and become the source of contaminants in the subsurface. The transport of the organic components through NAPL ...It occurs worldwide that the organic components of non-aqueous phase liquid (NAPL) enter the porous medium and become the source of contaminants in the subsurface. The transport of the organic components through NAPL interphase into the aqueous phase and the subsurface determines the extent of contamination, the persistence of residual NAPL phases and the techniques of remediation. During the transport process the NAPL interphase may experience "aging", a physical and chemical change when NAPL is exposed to aqueous and or gaseous phases. This aging process alters vice versa the mass transfer behaviour of the organic contaminants in the porous medium.展开更多
As an important part of the soil phosphorus(P)pool,organic P(OP)is widely found in terrestrial and aquatic environments(e.g.,soils and sediments).The interfacial behavior of OP on natural minerals affects the transpor...As an important part of the soil phosphorus(P)pool,organic P(OP)is widely found in terrestrial and aquatic environments(e.g.,soils and sediments).The interfacial behavior of OP on natural minerals affects the transport,transformation,and bioavailability of P in the environment.This paper reviews the processes involving adsorption-desorption,dissolution-precipitation,and enzymatic/mineral-mediated hydrolysis of OP at the mineral-water interface,and their subsequent effects on OP speciation and mineral colloidal stability/reactivity.The sorption mechanisms of OP on natural minerals mainly include surface complexation and precipitation,which are controlled by factors such as mineral identity and crystallinity,the relative molecular weight of OP,reaction pH,ionic strength,temperature,and co-existing ligands or ions.The desorption amount and rate of OP from minerals are determined by the mineral identity,desorbent type,pre-sorption time,OP species,reaction pH,number of desorption cycles,and redox status.The interactions between OP and minerals affect the sorption of co-existing metal ions and the stability of the minerals.The effect of minerals on the enzymatic hydrolysis of OP sorbed on mineral surfaces depends on the mineral identity and OP species.Some minerals also exhibit catalytic activity to promote the cleavage of C–O–P bonds and OP hydrolysis.We provide an overview of state-of-the-art techniques currently applied in environmental OP research.The main challenges and future research directions are also summarized to further explore OP interactions with natural minerals in complex environmental settings.展开更多
Oxidation of Mn (Ⅱ) or As(Ⅲ) by molecular oxygen is slow at pH<9,while they can be catalytically oxidized in the presence of oxide minerals and then removed from contaminated water.However,the reaction mechanisms...Oxidation of Mn (Ⅱ) or As(Ⅲ) by molecular oxygen is slow at pH<9,while they can be catalytically oxidized in the presence of oxide minerals and then removed from contaminated water.However,the reaction mechanisms on simultaneous oxidation of Mn(Ⅱ) and As (Ⅲ)on oxide mineral surface and their accompanied removal efficiency remain unclear.This study compared Mn (Ⅱ) oxidation on four common metal oxides (γ-Al_(2)O_(3),CuO,α-Fe2O_(3)and ZnO) and investigated the simultaneous oxidation and removal of Mn (Ⅱ) and As (Ⅲ) through batch experiments and spectroscopic analyses.Among the tested oxides,CuO and α-Fe2O_(3)possess greater catalytic activity toward Mn (Ⅱ) oxidation.Oxidation and removal kinetics of Mn (Ⅱ) and As (Ⅲ) on CuO indicate that O_(2)is the terminal electron acceptor for Mn (Ⅱ) and As (Ⅲ) oxidation on CuO,and Mn (Ⅱ) acts as an electron shuttle to promote As (Ⅲ) oxidation and removal.The main oxidized product of Mn (Ⅱ) on CuO is high-valent MnO_(x)species.This newly formed Mn (Ⅲ) or Mn (IV) phases promote As (Ⅲ) oxidation on CuO at circumneutral pH 8 and is reduced to Mn (Ⅱ),which may be then released into solution.This study provides new insights into metal oxide-catalyzed oxidation of pollutants Mn (Ⅱ) and As (Ⅲ) and suggests that CuO should be considered as an efficient material to remediate Mn (Ⅱ) and As(Ⅲ)contamination.展开更多
The network of microbial electron transfer can establish a syntrophic association of microbes by connecting interspecies metabolisms, and a variety of redox-active shuttles in environment have been proved to accelerat...The network of microbial electron transfer can establish a syntrophic association of microbes by connecting interspecies metabolisms, and a variety of redox-active shuttles in environment have been proved to accelerate the electron flow in a microbial community. Using humic substances as models, we investigated how different redox-active shuttles with different electrochemical properties influence interspecies electron transfer, and affect the shift of microbial communities. The co-culture of two species was constructed with supplements of humics, and the electron transfer between these two strains was found to be linked by humic acid with a wider window of redox potential and multi-peaks of redox reactions. Based on the shift of microbial composition, the humic substances with a wide potential window and multi-peaks of redox reactions for accepting and donating electrons could increase the biodiversity(Chao 1 and phylogenetic diversity) with a large extent. The mechanism by which redox-active shuttles mediate the microbial electron transfer network could facilitate our understanding of syntrophic interactions between microbes.展开更多
基金supported by the National Natural Science Foun-dation of China(Grants No.U21A2025 and 41907151)the National Key Research and Development Program of China(Grant No.2022YFD1700700).
文摘It is never an easy task for China to feed 1.4 billion people with only 7%of the world's arable land.With nearly 30%of the world's nitrogen(N)fertilizer applied,China achieves high crop yields while facing N pollution result-ing from excessive N input.Here,we calculate the farmland N budget on the national and regional scales.The N use efficiency(NUE)in China increased by 28.0%during 2005-2018.This improvement is due to the reduction in fertilization and the improvement of crop management.The fragmented farmland is changing to large-scale farmland with the increase in cultivated land area per rural population and the development of agricultural mech-anization.This opportunity brings more possibilities for precision farmland management,thus further improving NUE.The goal of an NUE of 0.6 may be achieved in the 2040s based on the current development trend.This striking N use shift in China has important implications for other developing countries.
基金financial support by the Deutsche Forschungsgemeinschaft as part of the research unit"Transport and Reactions in Porous Media"(HA 3453/6-2)
文摘Subcooled liquid solubility is the water solubility for a hypothetical state of liquid. It is an important parameter for multicomponent nonaqueous phase liquids （NAPLs） containing polycyclic aromatic hydrocarbons （PAHs）, which can exist as liquids even though most of the solutes are solid in their pure form at ambient temperature. So far, subcooled liquid solubilities were estimated from the solid water solubility and fugacity ratio of the solid and （subcooled） liquid phase, but rarely derived from experi- mental data. In our study, partitioning batch experiments were performed to determine the subcooled liquid solubility of PAHs in NAPL-water system. For selected PAH, a series of batch experiments were carried out at increased mole fractions of the target component in the NAPL and at a constant NAPL/ water volume ratio. The equilibrium aqueous PAH concentrations were measured with HPLC and/or GC- MS. The suhcooled liquid solubility was derived by extrapolation of the experimental equilibrium aqueous concentration to a mole fraction of unity. With the derived subcooled liquid solubility, the fugacity ratio and enthalpy of fusion of the solute were also estimated. Our results show a good agreement between the experimentally determined and published data.
基金support by the Director Foundation of Guangzhou Institute of Energy Conversion (No. Y107a21001)Deutsche Forschungsgemeinschaft as part of the research unit "Transport and Reactions in Porous Media" (HA 3453/6-1)
文摘It occurs worldwide that the organic components of non-aqueous phase liquid (NAPL) enter the porous medium and become the source of contaminants in the subsurface. The transport of the organic components through NAPL interphase into the aqueous phase and the subsurface determines the extent of contamination, the persistence of residual NAPL phases and the techniques of remediation. During the transport process the NAPL interphase may experience "aging", a physical and chemical change when NAPL is exposed to aqueous and or gaseous phases. This aging process alters vice versa the mass transfer behaviour of the organic contaminants in the porous medium.
基金supported by the National Natural Science Foundation of China(Nos.42030709 and 42167031).
文摘As an important part of the soil phosphorus(P)pool,organic P(OP)is widely found in terrestrial and aquatic environments(e.g.,soils and sediments).The interfacial behavior of OP on natural minerals affects the transport,transformation,and bioavailability of P in the environment.This paper reviews the processes involving adsorption-desorption,dissolution-precipitation,and enzymatic/mineral-mediated hydrolysis of OP at the mineral-water interface,and their subsequent effects on OP speciation and mineral colloidal stability/reactivity.The sorption mechanisms of OP on natural minerals mainly include surface complexation and precipitation,which are controlled by factors such as mineral identity and crystallinity,the relative molecular weight of OP,reaction pH,ionic strength,temperature,and co-existing ligands or ions.The desorption amount and rate of OP from minerals are determined by the mineral identity,desorbent type,pre-sorption time,OP species,reaction pH,number of desorption cycles,and redox status.The interactions between OP and minerals affect the sorption of co-existing metal ions and the stability of the minerals.The effect of minerals on the enzymatic hydrolysis of OP sorbed on mineral surfaces depends on the mineral identity and OP species.Some minerals also exhibit catalytic activity to promote the cleavage of C–O–P bonds and OP hydrolysis.We provide an overview of state-of-the-art techniques currently applied in environmental OP research.The main challenges and future research directions are also summarized to further explore OP interactions with natural minerals in complex environmental settings.
基金supported by the National Natural Science Foundation of China (Nos. 42030709, 42167031)the National Key Research and Development Program of China (No. 2017YFD0200201)Y.T. acknowledges support by the U.S. National Science Foundation (NSF) under Grant No. 2108688。
文摘Oxidation of Mn (Ⅱ) or As(Ⅲ) by molecular oxygen is slow at pH<9,while they can be catalytically oxidized in the presence of oxide minerals and then removed from contaminated water.However,the reaction mechanisms on simultaneous oxidation of Mn(Ⅱ) and As (Ⅲ)on oxide mineral surface and their accompanied removal efficiency remain unclear.This study compared Mn (Ⅱ) oxidation on four common metal oxides (γ-Al_(2)O_(3),CuO,α-Fe2O_(3)and ZnO) and investigated the simultaneous oxidation and removal of Mn (Ⅱ) and As (Ⅲ) through batch experiments and spectroscopic analyses.Among the tested oxides,CuO and α-Fe2O_(3)possess greater catalytic activity toward Mn (Ⅱ) oxidation.Oxidation and removal kinetics of Mn (Ⅱ) and As (Ⅲ) on CuO indicate that O_(2)is the terminal electron acceptor for Mn (Ⅱ) and As (Ⅲ) oxidation on CuO,and Mn (Ⅱ) acts as an electron shuttle to promote As (Ⅲ) oxidation and removal.The main oxidized product of Mn (Ⅱ) on CuO is high-valent MnO_(x)species.This newly formed Mn (Ⅲ) or Mn (IV) phases promote As (Ⅲ) oxidation on CuO at circumneutral pH 8 and is reduced to Mn (Ⅱ),which may be then released into solution.This study provides new insights into metal oxide-catalyzed oxidation of pollutants Mn (Ⅱ) and As (Ⅲ) and suggests that CuO should be considered as an efficient material to remediate Mn (Ⅱ) and As(Ⅲ)contamination.
基金supported by the National Natural Science Foundation of China(Grant Nos.41471260,21777155)
文摘The network of microbial electron transfer can establish a syntrophic association of microbes by connecting interspecies metabolisms, and a variety of redox-active shuttles in environment have been proved to accelerate the electron flow in a microbial community. Using humic substances as models, we investigated how different redox-active shuttles with different electrochemical properties influence interspecies electron transfer, and affect the shift of microbial communities. The co-culture of two species was constructed with supplements of humics, and the electron transfer between these two strains was found to be linked by humic acid with a wider window of redox potential and multi-peaks of redox reactions. Based on the shift of microbial composition, the humic substances with a wide potential window and multi-peaks of redox reactions for accepting and donating electrons could increase the biodiversity(Chao 1 and phylogenetic diversity) with a large extent. The mechanism by which redox-active shuttles mediate the microbial electron transfer network could facilitate our understanding of syntrophic interactions between microbes.
