An increase in atmospheric nitrogen （N） deposition can promote soil acidification, which may increase the release of ethylene （C2H4） under forest floors. Unfortunately, knowledge of whether increasing N deposition...An increase in atmospheric nitrogen （N） deposition can promote soil acidification, which may increase the release of ethylene （C2H4） under forest floors. Unfortunately, knowledge of whether increasing N deposition and C2H4 releases have synergistic effects on soil methane （CH4） uptake is limited and certainly deserves to be examined. We conducted some field measurements and laboratory experiments to examine this issue. The addition of （NH4）2SO4 or NH4Cl at a rate of 45 kg N ha-1 yr-1 reduced the soil CH4 uptake under a temperate old-growth forest in northeast China, and there were synergistic effects of N amendments in the presence of C2H4 concentrations equal to atmospheric CH4 concentration on the soil CH4 uptake, particularly in the NH4Cl-treated plots. Effective concentrations of added C2H4 on the soil CH4 uptake were smaller in NH＋4 -treated plots than in KNO3-treated plots. The concentration of ca 0.3 μl C2H4 L-1 in the headspace gases reduced by 20% soil atmospheric CH4 uptake in the NH4Cl-treated plots, and this concentration was easily produced in temperate forest topsoils under short-term anoxic conditions. Together with short-term stimulating effects of N amendments and soil acidification on C2H4 production from forest soils, our observations suggest that knowledge of synergistic effects of NH＋4 , rather than NO3- , amendments and C2H4 on the in situ soil CH4 uptake is critical for understanding the role of atmospheric N deposition and cycling of C2H4 under forest floors in reducing global atmospheric CH4 uptake by forests. Synergistic functions of NH4＋ -N deposition and C2H4 release due to soil acidification in reducing atmospheric CH4 uptake by forests are discussed.展开更多
Methane(CH_(4)) is the second largest longlived greenhouse gas after the CO_(2), which contributes 20% of global warming forcing. Global aerated soils remove CH_(4) from the troposphere, but the quantification of its ...Methane(CH_(4)) is the second largest longlived greenhouse gas after the CO_(2), which contributes 20% of global warming forcing. Global aerated soils remove CH_(4) from the troposphere, but the quantification of its magnitude and spatial variability is still of a large uncertainty. This study collected 1240records of the CH_(4) uptake by soils across the globe.Our estimates update the global soil CH_(4) sink to 31.9+/-0.16 Tg CH_(4) a^(-1), 42% higher than the previous inventory-based estimation, with 56% from temperate regions. Also, our dataset revealed that the global drylands dominated the soil CH_(4) sink, which is different from traditional forest-dominated view.During the past four decades, the soil porosity affected by soil moisture controls the variation in the uptake in the tropics, while warming temperatures benefit methanotrophs in temperate and boreal soils,especially the drylands, where the soil porosity is not limiting. Our simulations indicate that the CH_(4) uptake will increase by 11%–31% by the end of the 21st century, much lower than the previous estimations.This study substantially constrains the global soil CH_(4) sink estimates and reveals the warming temperate northern hemisphere is a dominant CH_(4) uptake region in the past and future, while the uptake decreases in tropical soils under increasing precipitation.展开更多
Porous supramolecular frameworks based on metal-organic cages(MOCs)usually have poor structural stability after activation.This issue narrows the scope of their potential applications,particularly for the inclusion of...Porous supramolecular frameworks based on metal-organic cages(MOCs)usually have poor structural stability after activation.This issue narrows the scope of their potential applications,particularly for the inclusion of vip molecules that demand high porosity.Herein,the authors have reported the stabilization of a mesoporous zirconium MOC-based supramolecular framework with an in situ catalytic polymerization strategy.Due to the passivation effect imparted by this strategy,the introduced polymer is primarily distributed on the surface of the crystals,which results in the hybrid material retaining its crystallinity and permanent porosity.A preliminary application of this type of stabilized mesoporous supramolecular framework shows that among MOC-based supramolecular frameworks,it has the highest high-pressure methane uptake.Such a facile strategy may provide a general way to stabilize fragile porous materials and facilitate exploration of their potential applications.展开更多
The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs u...The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs under harsh operating conditions.Herein,a highly stable microporous MOF based on the Fe_(3)O cluster(PCN-678)has been synthesized using a tetracarboxylate ligand.Utilizing symmetry reduced tetratopic carboxylate ligand,a mesoporous MOF(PCN-668)could be obtained in which nanoscale cage-like building units and one-dimensional(1D)channels coexist.The neighboring cages were mutual diastereomers in PCN-668 due to the further reduction of the Cs symmetry of the free ligand to C1 symmetry after self-assembly.Furthermore,the acid stability of this mesoporous MOF was improved via postsynthetic metal exchange to chromium(PCN-668-Cr).The PCN-668-Cr exhibited very high stability in both acidic and basic aqueous solutions(pH=1–11).Additionally,the mesoporous MOF showed a high total gravimetric methane uptake(∼500 cm^(3) g^(−1) at 100 bar),while the microporous MOF showed a high volumetric methane storage capacity of 147 cm3 cm−3 at room temperature.展开更多
基金funded jointly by the National Natural Science Foundation of China (Grant Nos. 41021004, 20777071 and 20477044)the Key Project of Knowledge Innovation Program from the Chinese Academy of Sciences (KZCX2-YW-432)the Hundred Talents Project from the Chinese Academy of Sciences
文摘An increase in atmospheric nitrogen （N） deposition can promote soil acidification, which may increase the release of ethylene （C2H4） under forest floors. Unfortunately, knowledge of whether increasing N deposition and C2H4 releases have synergistic effects on soil methane （CH4） uptake is limited and certainly deserves to be examined. We conducted some field measurements and laboratory experiments to examine this issue. The addition of （NH4）2SO4 or NH4Cl at a rate of 45 kg N ha-1 yr-1 reduced the soil CH4 uptake under a temperate old-growth forest in northeast China, and there were synergistic effects of N amendments in the presence of C2H4 concentrations equal to atmospheric CH4 concentration on the soil CH4 uptake, particularly in the NH4Cl-treated plots. Effective concentrations of added C2H4 on the soil CH4 uptake were smaller in NH＋4 -treated plots than in KNO3-treated plots. The concentration of ca 0.3 μl C2H4 L-1 in the headspace gases reduced by 20% soil atmospheric CH4 uptake in the NH4Cl-treated plots, and this concentration was easily produced in temperate forest topsoils under short-term anoxic conditions. Together with short-term stimulating effects of N amendments and soil acidification on C2H4 production from forest soils, our observations suggest that knowledge of synergistic effects of NH＋4 , rather than NO3- , amendments and C2H4 on the in situ soil CH4 uptake is critical for understanding the role of atmospheric N deposition and cycling of C2H4 under forest floors in reducing global atmospheric CH4 uptake by forests. Synergistic functions of NH4＋ -N deposition and C2H4 release due to soil acidification in reducing atmospheric CH4 uptake by forests are discussed.
基金supported by the Second Tibetan Plateau Scientific Exploration (2019QZKK0404)the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20020401)+1 种基金the Youth Innovation Promotion Association Chinese Academy of Sciences (2020369)the National Natural Scientific Foundation of China (41971145)。
文摘Methane(CH_(4)) is the second largest longlived greenhouse gas after the CO_(2), which contributes 20% of global warming forcing. Global aerated soils remove CH_(4) from the troposphere, but the quantification of its magnitude and spatial variability is still of a large uncertainty. This study collected 1240records of the CH_(4) uptake by soils across the globe.Our estimates update the global soil CH_(4) sink to 31.9+/-0.16 Tg CH_(4) a^(-1), 42% higher than the previous inventory-based estimation, with 56% from temperate regions. Also, our dataset revealed that the global drylands dominated the soil CH_(4) sink, which is different from traditional forest-dominated view.During the past four decades, the soil porosity affected by soil moisture controls the variation in the uptake in the tropics, while warming temperatures benefit methanotrophs in temperate and boreal soils,especially the drylands, where the soil porosity is not limiting. Our simulations indicate that the CH_(4) uptake will increase by 11%–31% by the end of the 21st century, much lower than the previous estimations.This study substantially constrains the global soil CH_(4) sink estimates and reveals the warming temperate northern hemisphere is a dominant CH_(4) uptake region in the past and future, while the uptake decreases in tropical soils under increasing precipitation.
基金This study was financially supported by the National Nature Science Foundation of China(nos.21771177 and 51603206)the Strategic Priority Research Program of CAS(no.XDB20000000)the Key Research Program of Frontier Sciences,CAS(no.QYZDB-SSW-SLH019).
文摘Porous supramolecular frameworks based on metal-organic cages(MOCs)usually have poor structural stability after activation.This issue narrows the scope of their potential applications,particularly for the inclusion of vip molecules that demand high porosity.Herein,the authors have reported the stabilization of a mesoporous zirconium MOC-based supramolecular framework with an in situ catalytic polymerization strategy.Due to the passivation effect imparted by this strategy,the introduced polymer is primarily distributed on the surface of the crystals,which results in the hybrid material retaining its crystallinity and permanent porosity.A preliminary application of this type of stabilized mesoporous supramolecular framework shows that among MOC-based supramolecular frameworks,it has the highest high-pressure methane uptake.Such a facile strategy may provide a general way to stabilize fragile porous materials and facilitate exploration of their potential applications.
基金supported by the Center for Gas Separations,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences(no.DESC0001015)Structural analyses were supported by the Robert A.Welch Foundation through a Welch Endowed Chair to H.-C.Z.(A-0030)+3 种基金The National Science Foundation Graduate Research Fellowship(DGE:1252521)is gratefully acknowledged.The authors also acknowledge the financial support of the U.S.Department of Energy Office of Fossil Energy,National Energy Technology Laboratory(no.DE-FE0026472)and National Science Foundation Small Business Innovation Research(NSFSBIR)under grant no.(1632486)the financial support of the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDB20000000)National Nature Science Foundation of China(no.21871266),CAS(no.QYZDY-SSWSLH025),and Youth Innovation Promotion Association CAS.
文摘The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs under harsh operating conditions.Herein,a highly stable microporous MOF based on the Fe_(3)O cluster(PCN-678)has been synthesized using a tetracarboxylate ligand.Utilizing symmetry reduced tetratopic carboxylate ligand,a mesoporous MOF(PCN-668)could be obtained in which nanoscale cage-like building units and one-dimensional(1D)channels coexist.The neighboring cages were mutual diastereomers in PCN-668 due to the further reduction of the Cs symmetry of the free ligand to C1 symmetry after self-assembly.Furthermore,the acid stability of this mesoporous MOF was improved via postsynthetic metal exchange to chromium(PCN-668-Cr).The PCN-668-Cr exhibited very high stability in both acidic and basic aqueous solutions(pH=1–11).Additionally,the mesoporous MOF showed a high total gravimetric methane uptake(∼500 cm^(3) g^(−1) at 100 bar),while the microporous MOF showed a high volumetric methane storage capacity of 147 cm3 cm−3 at room temperature.
