The hard-to-remove lattice water has been regarded as a significant obstacle impeding the practical use of Prussian blue analogue cathodes for sodium-ion batteries.This work monitored the electrochemical evolution of ...The hard-to-remove lattice water has been regarded as a significant obstacle impeding the practical use of Prussian blue analogue cathodes for sodium-ion batteries.This work monitored the electrochemical evolution of a hydrated monoclinic sodium manganese hexacyanoferrate cathode by solid-state nuclear magnetic resonance(NMR).For the first time,we established a correlation between the chemical shifts of ^(23)Na NMR signals and the presence or absence of lattice water within this cathode.Through this method,we verified the electrochemical dehydration process that coincides with the merging of two redox platforms and a phase transformation in the initial cycles.Furthermore,we discovered that the lattice water is completely removed after several-day cell rest following a single activation cycle.展开更多
In this context,the present study proposes the use of microwave irradiation to improve the dehydration rate and efficiency of strontium hydroxide octahydrate(Sr(OH)_(2)·8H_(2)O)without introducing contaminants.Th...In this context,the present study proposes the use of microwave irradiation to improve the dehydration rate and efficiency of strontium hydroxide octahydrate(Sr(OH)_(2)·8H_(2)O)without introducing contaminants.This study revealed that the use of microwave irradiation to dehydrate Sr(OH)_(2)·8H_(2)O is feasible and surprisingly efficient.The effects of this approach on important parameters were investigated using response surface methodology(RSM).The results revealed that the microwave dehydration process follows a linear polynomial model.In addition,compared with the heating time and material thickness,the microwave-assisted dehydration of Sr(OH)_(2)·8H_(2)O is sensitive to the microwave power and not to the material mass.The relative dehydration percentage reached 99.99%when heated in a microwave oven at 950Wfor just 3 min.In contrast,a relative dehydration percentage of 94.6%was reached when heated in an electric furnace at 180℃for 120 min.The XRD spectra also revealed that most of the Sr(OH)_(2)·8H_(2)O transformed into Sr(OH)_(2)after dehydration via microwave irradiation,whereas a significant portion of the Sr(OH)_(2)·H_(2)O remained after conventional electric dehydration.The experimental data were fitted and analyzed via the thin-layer drying dynamics model,and the results indicated that the dehydrating behavior of Sr(OH)_(2)·8H_(2)O could be well described by the Page model.展开更多
Isosorbide is a novel bio-based material derived as a secondary dehydration product of sorbitol.This work focuses on the kinetics of sulfuric acid-catalyzed dehydration of sorbitol under conditions of nonconstant volu...Isosorbide is a novel bio-based material derived as a secondary dehydration product of sorbitol.This work focuses on the kinetics of sulfuric acid-catalyzed dehydration of sorbitol under conditions of nonconstant volume.Herein,the effects of stirring rate,catalyst dosage,reaction temperature,and reaction time on the dehydration reaction of sorbitol were investigated.The yield of isosorbide up to 77.13%was obtained after 1.5 h of reaction time under conditions of 2 kPa,1.0%(mass)catalyst dosage,and 413.15 K.Based on the sorbitol dehydration reaction mechanism and a simplified reaction network,a kinetic model was developed in this work.A good agreement was accomplished between kinetic modeling and experiments between 393.15 and 423.15 K.The fitting results indicate that side reactions with higher activation energies are more affected by reaction temperatures,and the main side reaction that influences the selectivity of isosorbide is the oligomerization reaction among the primary dehydration products of sorbitol.The model fitting of the catalyst amounts effect shows that the effective concentration of sulfuric acid would be reduced with the increase of dosage due to the molecular agglomeration effect.Hopefully,the kinetic experiments and modeling results obtained in this work will be helpful to the design and optimization of the industrial sorbitol dehydration process.展开更多
Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adu...Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adults of the migratory locust,Locusta migratoria,were subjected to food-mediated dehydration,and adipokinetic hormone(AKH)signaling was found to play a key role in regulating dehydration resistance.Specifically,dehydration shortened the lifespan,increased the body weight loss,and reduced the water loss rate in adult locusts.Global transcriptome profiles revealed variations in tissue-specific gene expression between dehydration-resistant locusts and normal locusts.Importantly,dehydration selection and exposure induced prominent expression of AKH genes in the retrocerebral complex of adult locusts.Furthermore,individual knockdown of AKH1,AKH2,or AKH receptor(AKHR)accelerated water loss and shortened the lifespan of adult locusts under dehydration conditions,and trehalose supplementation ameliorated the negative effects caused by interference with AKH or AKHR.These findings demonstrated that AKH/AKHR signaling-dependent trehalose metabolism plays a crucial role in regulating locust dehydration resistance and thus provide novel insights into the regulatory mechanism underlying drought resistance.展开更多
Significant waste resources are generated in the form of water-oil emulsions.These emulsions cannot be effectively destroyed on an industrial scale by traditional methods that rely on the settling of the aqueous phase...Significant waste resources are generated in the form of water-oil emulsions.These emulsions cannot be effectively destroyed on an industrial scale by traditional methods that rely on the settling of the aqueous phase,and therefore,they accumulate in large quantities.Thermomechanical dehydration,based on the evaporation of the water phase,presents a promising process for recycling such waste.However,within the framework of thermomechanical dehydration,the issue of optimizing energy costs for heating raw materials and controlling the water content in the product arises.Standard methods of determining water content under the boiling conditions of highly stable water-hydrocarbon emulsions are characterized by low efficiency,as they require constant sampling and the involvement of additional equipment and personnel.Consequently,this presents a challenge in predicting and creating an automated thermomechanical dehydration process.Therefore,dynamic curves depicting changes in the water content of these emulsions,depending on the temperature of the boiling liquid,have been obtained.It is proposed to determine the rate of temperature increase(dT/dt)of the boiling emulsion for continuous,real-time monitoring of the residual water content and for recording the moment of complete dehydration.Achieving a boiling emulsion temperature of 130-170℃(or higher)and/or the rate of temperature increase from 3.0 to 5.5(or above)indicates the complete dehydration of the emulsion.The proposed method can be implemented in any industrial or laboratory-scale unit for thermomechanical dehydration without significant capital costs.It is based on the use of simple devices consisting of temperature sensors and a computing unit for determining the temperature and rate of heating.展开更多
In recent decades,MgSO_(4)·7H_(2)O(epsomite)has attracted significant attention as a promising thermochemical-based thermal energy storage material due to its high theoretical energy density,wide availability,and...In recent decades,MgSO_(4)·7H_(2)O(epsomite)has attracted significant attention as a promising thermochemical-based thermal energy storage material due to its high theoretical energy density,wide availability,and affordability.Despite extensive research efforts,progress in achieving high-energy density has been limited,primarily due to inadequate understanding of its reaction mechanisms and unfavorable dehydration/hydration kinetics.This study systematically investigated the hydration/dehydration kinetics and cyclability of MgSO_(4)·7H_(2)O.The results reveal that the dehydration process is influenced by the heating rate,with an optimal rate of 5℃/min,resulting in a seven-step MgSO_(4)·7H_(2)O dehydration process with a dehydration heat close to the theoretical value.The reaction kinetic analysis indicated that the rate of hydration was approximately 50%lower than that of dehydration.In addition,thermal cycling tests of MgSO_(4)·7H_(2)O under the conditions of this study(small sample size)indicated good cyclability,with hydration rates increasing with increasing cycling numbers up to approximately 10 cycles where level-off occurs.These results are consistent with scanning electron microscopy analyses,which revealed the formation of cracks and channels in the salt hydrate particles,facilitating mass transfer and improved kinetics.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.22272055)Scientific and Technological Project of Henan Province(No.222102240081)+1 种基金Science and Technology Planning Project of Anyang City(No.2022C01GX023)the support from Shanghai Synchrotron Radiation Facility(BL14B)for the sXRD experiments.
文摘The hard-to-remove lattice water has been regarded as a significant obstacle impeding the practical use of Prussian blue analogue cathodes for sodium-ion batteries.This work monitored the electrochemical evolution of a hydrated monoclinic sodium manganese hexacyanoferrate cathode by solid-state nuclear magnetic resonance(NMR).For the first time,we established a correlation between the chemical shifts of ^(23)Na NMR signals and the presence or absence of lattice water within this cathode.Through this method,we verified the electrochemical dehydration process that coincides with the merging of two redox platforms and a phase transformation in the initial cycles.Furthermore,we discovered that the lattice water is completely removed after several-day cell rest following a single activation cycle.
基金supported by the Research Program of the Science and Technology Department of Guizhou Province(Qiankehe Jichu[2019]1418)the Research Program of Talented Scholars of Guizhou Institute of Technology(XJGC20190965).
文摘In this context,the present study proposes the use of microwave irradiation to improve the dehydration rate and efficiency of strontium hydroxide octahydrate(Sr(OH)_(2)·8H_(2)O)without introducing contaminants.This study revealed that the use of microwave irradiation to dehydrate Sr(OH)_(2)·8H_(2)O is feasible and surprisingly efficient.The effects of this approach on important parameters were investigated using response surface methodology(RSM).The results revealed that the microwave dehydration process follows a linear polynomial model.In addition,compared with the heating time and material thickness,the microwave-assisted dehydration of Sr(OH)_(2)·8H_(2)O is sensitive to the microwave power and not to the material mass.The relative dehydration percentage reached 99.99%when heated in a microwave oven at 950Wfor just 3 min.In contrast,a relative dehydration percentage of 94.6%was reached when heated in an electric furnace at 180℃for 120 min.The XRD spectra also revealed that most of the Sr(OH)_(2)·8H_(2)O transformed into Sr(OH)_(2)after dehydration via microwave irradiation,whereas a significant portion of the Sr(OH)_(2)·H_(2)O remained after conventional electric dehydration.The experimental data were fitted and analyzed via the thin-layer drying dynamics model,and the results indicated that the dehydrating behavior of Sr(OH)_(2)·8H_(2)O could be well described by the Page model.
文摘Isosorbide is a novel bio-based material derived as a secondary dehydration product of sorbitol.This work focuses on the kinetics of sulfuric acid-catalyzed dehydration of sorbitol under conditions of nonconstant volume.Herein,the effects of stirring rate,catalyst dosage,reaction temperature,and reaction time on the dehydration reaction of sorbitol were investigated.The yield of isosorbide up to 77.13%was obtained after 1.5 h of reaction time under conditions of 2 kPa,1.0%(mass)catalyst dosage,and 413.15 K.Based on the sorbitol dehydration reaction mechanism and a simplified reaction network,a kinetic model was developed in this work.A good agreement was accomplished between kinetic modeling and experiments between 393.15 and 423.15 K.The fitting results indicate that side reactions with higher activation energies are more affected by reaction temperatures,and the main side reaction that influences the selectivity of isosorbide is the oligomerization reaction among the primary dehydration products of sorbitol.The model fitting of the catalyst amounts effect shows that the effective concentration of sulfuric acid would be reduced with the increase of dosage due to the molecular agglomeration effect.Hopefully,the kinetic experiments and modeling results obtained in this work will be helpful to the design and optimization of the industrial sorbitol dehydration process.
基金supported by the National Key Research and Development Program of China(2022YFD1400503)the National Natural Science Foundation of China(32102208)the Hebei Natural Science Foundation,China(C2022201042,C2021201052 and C2023201075).
文摘Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adults of the migratory locust,Locusta migratoria,were subjected to food-mediated dehydration,and adipokinetic hormone(AKH)signaling was found to play a key role in regulating dehydration resistance.Specifically,dehydration shortened the lifespan,increased the body weight loss,and reduced the water loss rate in adult locusts.Global transcriptome profiles revealed variations in tissue-specific gene expression between dehydration-resistant locusts and normal locusts.Importantly,dehydration selection and exposure induced prominent expression of AKH genes in the retrocerebral complex of adult locusts.Furthermore,individual knockdown of AKH1,AKH2,or AKH receptor(AKHR)accelerated water loss and shortened the lifespan of adult locusts under dehydration conditions,and trehalose supplementation ameliorated the negative effects caused by interference with AKH or AKHR.These findings demonstrated that AKH/AKHR signaling-dependent trehalose metabolism plays a crucial role in regulating locust dehydration resistance and thus provide novel insights into the regulatory mechanism underlying drought resistance.
文摘Significant waste resources are generated in the form of water-oil emulsions.These emulsions cannot be effectively destroyed on an industrial scale by traditional methods that rely on the settling of the aqueous phase,and therefore,they accumulate in large quantities.Thermomechanical dehydration,based on the evaporation of the water phase,presents a promising process for recycling such waste.However,within the framework of thermomechanical dehydration,the issue of optimizing energy costs for heating raw materials and controlling the water content in the product arises.Standard methods of determining water content under the boiling conditions of highly stable water-hydrocarbon emulsions are characterized by low efficiency,as they require constant sampling and the involvement of additional equipment and personnel.Consequently,this presents a challenge in predicting and creating an automated thermomechanical dehydration process.Therefore,dynamic curves depicting changes in the water content of these emulsions,depending on the temperature of the boiling liquid,have been obtained.It is proposed to determine the rate of temperature increase(dT/dt)of the boiling emulsion for continuous,real-time monitoring of the residual water content and for recording the moment of complete dehydration.Achieving a boiling emulsion temperature of 130-170℃(or higher)and/or the rate of temperature increase from 3.0 to 5.5(or above)indicates the complete dehydration of the emulsion.The proposed method can be implemented in any industrial or laboratory-scale unit for thermomechanical dehydration without significant capital costs.It is based on the use of simple devices consisting of temperature sensors and a computing unit for determining the temperature and rate of heating.
文摘In recent decades,MgSO_(4)·7H_(2)O(epsomite)has attracted significant attention as a promising thermochemical-based thermal energy storage material due to its high theoretical energy density,wide availability,and affordability.Despite extensive research efforts,progress in achieving high-energy density has been limited,primarily due to inadequate understanding of its reaction mechanisms and unfavorable dehydration/hydration kinetics.This study systematically investigated the hydration/dehydration kinetics and cyclability of MgSO_(4)·7H_(2)O.The results reveal that the dehydration process is influenced by the heating rate,with an optimal rate of 5℃/min,resulting in a seven-step MgSO_(4)·7H_(2)O dehydration process with a dehydration heat close to the theoretical value.The reaction kinetic analysis indicated that the rate of hydration was approximately 50%lower than that of dehydration.In addition,thermal cycling tests of MgSO_(4)·7H_(2)O under the conditions of this study(small sample size)indicated good cyclability,with hydration rates increasing with increasing cycling numbers up to approximately 10 cycles where level-off occurs.These results are consistent with scanning electron microscopy analyses,which revealed the formation of cracks and channels in the salt hydrate particles,facilitating mass transfer and improved kinetics.
