High ammonia-nitrogen digestate has become a key bottleneck limiting the anaerobic digestion of organic solid waste.Vacuum ammonia stripping can simultaneously remove and recover ammonia nitrogen,which has attracted a...High ammonia-nitrogen digestate has become a key bottleneck limiting the anaerobic digestion of organic solid waste.Vacuum ammonia stripping can simultaneously remove and recover ammonia nitrogen,which has attracted a lot of attention in recent years.To investigate the parameter effects on the efficiency and mass transfer,five combination conditions(53℃ 15 kPa,60°C 20 kPa,65°C 25 kPa,72°C 35 kPa,and 81°C 50 kPa)were conducted for ammonia stripping of sludge digestate.The results showed that 80%of ammonia nitrogen was stripped in 45 min for all experimental groups,but the ammonia transfer coefficient varied under different conditions,which increased with the rising of boiling point temperature,and reached the maximum value(39.0 mm/hr)at 81°C 50 kPa.The ammonia nitrogen removal efficiency was more than 80%for 30 min vacuum stripping after adjusting the initial pH to above 9.5,and adjustment of the initial alkalinity also affects the pH value of liquid digestate.It was found that pH and alkalinity are the key factors influencing the ammonia nitrogen dissociation and removal efficiency,while temperature and vacuum mainly affect the ammonia nitrogen mass transfer and removal velocity.In terms of the mechanism of vacuum ammonia stripping,it underwent alkalinity destruction,pH enhancement,ammonia nitrogen dissociation,and free ammonia removal.In this study,two-stage experiments of alkalinity destruction and ammonia removal were also carried out,which showed that the two-stage configuration was beneficial for ammonia removal.It provides a theoretical basis and practical technology for the vacuum ammonia stripping from liquid digestate of organic solid waste.展开更多
Continuous-flow upgrading of pentaerythritol synthesis technology via base-catalyzed aldol and Cannizzaro reactions of formaldehyde and acetaldehyde faces the challenge of effectively controlling the critical side rea...Continuous-flow upgrading of pentaerythritol synthesis technology via base-catalyzed aldol and Cannizzaro reactions of formaldehyde and acetaldehyde faces the challenge of effectively controlling the critical side reaction of hydroxymethyl acetaldehyde(HA)to the acrolein intermediate.Here,we first identified the forms of industrial formaldehyde as methane diol that easily converts to the alkaline formaldehyde under alkaline(NaOH)environment.The carbonyl group of alkaline formaldehyde induces deprotonation of acetaldehyde instead of the recognized base-hydroxyl group-induced deprotonation,and it needs to overcome only 18.31 kcal·mol^(-1)(1 kcal=4.186 kJ)energy barrier to form key intermediates of HA.The sodium solvation cage formed by NaOH hexa-coordinated formaldehyde effectively inhibits the alkalinity,thus contributing to a high energy barrier(46.21 kcal·mol^(-1))to unwanted acrolein formation.In addition,the solvation cage gradually opens to increase the alkalinity with the consumption of formaldehyde,thus facilitating the subsequent Cannizzaro reaction(to overcome 11.77 kcal·mol^(-1)).In comparison,strong alkalinity promotes the formation of acrolein(36.65 kcal·mol^(-1))to initiate the acetal side reaction,while weak alkalinity reduces the possibility of the Cannizzaro reaction(to overcome 20.44 kcal·mol^(-1)).This theoretically reveals the importance of the segmented feeding of weak and strong bases to successively control the aldol reaction and Cannizzaro reaction,and the combination of Na_(2)CO_(3) or HCOONa with NaOH improves the pentaerythritol yield by 7%to 13%compared to that of NaOH alone(70%yield)within 1 min at a throughput of 155.7 ml·min^(-1).展开更多
Ion-solvaing membranes(ISMs)have received extensive attention in recent years as a key component in electrochemical energy conversion and storage devices.This article provides an overview of structural composition,per...Ion-solvaing membranes(ISMs)have received extensive attention in recent years as a key component in electrochemical energy conversion and storage devices.This article provides an overview of structural composition,performance advan-tages,research progress,ion conduction mechanism and existing issues of ISMs,primarily classifying them according to the matrix structure.A detailed analysis of performance enhancement methods,key performance indicators of ISMs and performance influencing factors is also presented.The article contributes to further optimizing the design and application of ion-solvation membranes,providing theoretical support for the development of fields such as hydrogen production through electrolysis of water and electrochemical energy in the future.展开更多
Homret Ghannam alkali feldspar granite(HGAFG)in the central Eastern Desert(CED)of Egypt represents a distinctive example of late Neoproterozoic magmatism in the Arabian-Nubian Shield(ANS).This study integrates field o...Homret Ghannam alkali feldspar granite(HGAFG)in the central Eastern Desert(CED)of Egypt represents a distinctive example of late Neoproterozoic magmatism in the Arabian-Nubian Shield(ANS).This study integrates field observations,petrography,mineral chemistry(EMPA),and whole-rock geochemistry to investigate its petrogenesis,geodynamic evolution,and rare-metal potential.HGAFG comprises two cogenetic varieties,alkali feldspar granite and riebeckite-bearing granite,hosting rare-metal minerals such as zircon,fluorite,columbite and apatite.HGAFG exhibits diagnostic A-type geochemical characteristics,including high SiO₂contents(73.81-77.86 wt%),metaluminous to mildly peralkaline composition(ASI:0.92-1.03),enrichment in HFSE(Zr≈791.80 ppm,Nb≈68.12 ppm,Y≈90.81 ppm)andΣREE(103.40-475.57 ppm),and pronounced negative Eu anomalies(Eu/Eu^(*)=0.07-0.20).Zircon saturation thermometry yields high crystallization temperatures(TZr≈908.87℃)and low emplacement pressures(1.46 kbar)under reducing conditions(ƒO_(2)≈−11.5).The mineralogical and geochemical results reveal that HGAFG originated from a hybrid,fluorine-rich magma generated by anatexis of lower crust,followed by extensive fractional crystallization,during late post-collisional extension associated with lithospheric delamination.The reduced nature and fluorine enrichment of HGAFG magma promoted the mineralization of Nb-Ta-REE phases,highlighting its significance as a fertile,high-temperature product of the terminal magmatic stage in ANS evolution.展开更多
Plant-related organic compound(PROC)may interact with redox-active metals like iron while they are present in soil or aquatic environment,but their effects on the photoreduction of Fe(III)remain largely unexplored.Thi...Plant-related organic compound(PROC)may interact with redox-active metals like iron while they are present in soil or aquatic environment,but their effects on the photoreduction of Fe(III)remain largely unexplored.This study investigates the photochemical behavior of Fe(III)-PROC complexes using alkaline lignin(AL),betaine hydrochloride(BH),and phytic acid(PA)as representative proxies for PROC.The reductive agent AL demonstrated the ability to directly reduce Fe(III)to Fe(II).In contrast,BH,being unable to form strong complexes with Fe(III),was able to quench·OH,thereby resulting in a shift of the redox equilibrium towards Fe(II).PA exhibited a strong binding affinity for Fe(III),effectively inhibiting its photoreduction.Electron paramagnetic resonance(EPR)analysis,utilizing 5,5-dimethyl-1-pyrroline-N-oxide(DMPO)as a spin trap,revealed that the DMPO-OH signal detected in photolyzed Fe(III)-PROC solutions originated from various pathways.Specifically,uncomplexed Fe(III)in AL or BH solutions was shown to oxidize DMPO directly,leading to the formation of a false DMPO-OH adduct.The addition of ethanol to the photolyzed Fe(III)-AL and Fe(III)-BH systems resulted in the generation of the DMPO-CH(CH_(3))OH adduct,thereby confirming the presence of authentic·OH in these systems.The photolysis of the Fe(III)-PA complex may proceed via a photodissociation mechanism,where the resulting loosely bound Fe(III)can oxidize DMPO,followed by a nucleophilic attack from water.This research highlights the multifaceted roles of PROC in facilitating the redox cycling of iron within soil and aquatic ecosystems.展开更多
Examining carbonate dissolution kinetics at mineral-water interface is crucial to understand numerous environmental and geochemical processes,including global carbon cycling,CO_(2)sequestration in deep geological rese...Examining carbonate dissolution kinetics at mineral-water interface is crucial to understand numerous environmental and geochemical processes,including global carbon cycling,CO_(2)sequestration in deep geological reservoirs,and trace elements release in terrestrial and aquatic environments.Here we explored the effect of circumneutral to alkaline pH solutions(pH 6-11)on dissolution kinetics of pure dolomite and Ca and Mg release stoichiometry in flow-through reactor experiments at 25±1℃.Results revealed that the dolomite dissolution rates obtained from effluent Ca and Mg concentrations(R_(Ca)and R_(Mg)in mol/cm^(2)/s)were dependent on input solution pH and HCO_(3)^(-)log activity.The pH dependence of dissolution rates showed two distinct trends,i.e.,at circumneutral pH ranging between 6 and 8,the dissolution rate decreased with increasing pH,with minimum rate at pH 8.While in the highly alkaline pH range(pH 9-11),the dolomite dissolution rate increased with an increasing pH.Irrespective of the input pH,the dolomite dissolution rates indicated a reverse relationship with HCO_(3)^(-)log activity,with the lowest dissolution rate(R Ca=3.80×10^(-12)mol/cm^(2)/s)at pH 8 where HCO_(3)^(-)log activity attained the highest value(-3.957).The lower R Ca and R Mg obtained at pH 8 compared to all the other pH could possibly be attributed to an inhibition caused by high HCO_(3)^(-)log activity in solution at this pH.Dolomite dissolution rates were non-stoichiometric at all the experimental pH values,showing higher preferential Ca over Mg release(R_(Ca)>R_(Mg))whereas an opposite trend was observed at pH 8,with R_(Ca)<R_(Mg)at the steady state.Saturation index values calculated using geochemical speciation modelling were positive for Mg-bearing minerals(brucite,dolomite,artinite)at alkaline pH of 10-11,indicating favourable conditions for their precipitation under studied conditions.This study provides insights on the significance of log ion activities of HCO_(3)^(-)and Me-OH^(+)under varying pH for elucidating the dissolution mechanism of dolomite in circumneutral to alkaline aqueous environments.展开更多
NiMo-based catalysts show significant potential for the hydrogen evolution reaction(HER).Optimizing the electronic structure and enhancing mass transfer are two critical factors for improving catalytic performance,but...NiMo-based catalysts show significant potential for the hydrogen evolution reaction(HER).Optimizing the electronic structure and enhancing mass transfer are two critical factors for improving catalytic performance,but they remain significant challenges.Herein,we present a route for synthesizing two-dimensional(2D)porous Mo_(2)N-Ni heterojunction nanosheets with tuned Ni-Mo ratio for enhanced alkaline HER performance.A precursor can be easily synthesized by assembling polyoxometalate clusters(PMo_(12))with layered hydroxy oxides(Ni(OH)_(2)).It is found that the interaction between PMo_(12)and Ni(OH)_(2)can effectively protect the particles from significant agglomeration during pyrolysis,resulting in the formation of 2D porous sheets composed of small Mo_(2)N-Ni units.The transfer of electrons from Ni to Mo_(2)N results in the redistribution of electrons at the heterojunction,optimizing the adsorption and desorption of intermediates.Moreover,the 2D porous structure comprised of small particles enhances mass transfer,thereby reducing the impedance of the catalyst.Consequently,the catalyst with an optimized Mo/Ni ratio exhibits an overpotential of 19 mV at 10 mA cm^(-2),being comparable to that of commercial Pt/C catalyst.The anion exchange membrane(AEM)electrolyzer,consisting of optimized Mo_(2)N-Ni and NiFe-LDH,achieves a current density of 500 mA cm^(-2)at 1.80 V and can operate stably for 300 h.This assembly method offers an effective strategy for the large-scale preparation of efficient catalysts.展开更多
The accumulation of refractory organics in Bayer liquor(pH 14.4)critically compromises aluminum production efficiency and product quality,necessitating sustainable remediation strategies.Herein,we develop an ultrasoni...The accumulation of refractory organics in Bayer liquor(pH 14.4)critically compromises aluminum production efficiency and product quality,necessitating sustainable remediation strategies.Herein,we develop an ultrasonic-driven catalytic ozonation system with dynamically reconstructed CuO/Cu2O heterointerfaces,achieving unprecedented efficiency in extreme alkaline wastewater treatment.Atomic-scale interface engineering endows the catalyst with hydrophilicity(contact angle:6.1°)and 3.8–4.3 times higher oxygen vacancy density compared to single-phase catalysts.These properties facilitate efficient interfacial interactions with Bayer liquor and enable superior ozone activation through synergistic Cu(I)/Cu(II)redox cycling across the heterointerface.This interfacial synergy reduces ozone adsorption energy from 5.46 eV(Cu_(2)O)to 1.48 eV,driving the generation of reactive oxygen species(ROS)via low-energy pathways.Under optimized conditions,the system achieves 57.82%TOC removal within 1.5 h with 2.3-fold faster kinetics than ozone–alone processes,while improving energy efficiency by 1.82–3.22 times per kWh over conventional thermal oxidation.Remarkable stability is demonstrated through 80.21%activity retention after 6 cycles,attributed to surface energy minimization(0.61 J m^(−2)),alongside 67.91%hydroxyl radical(•OH)-mediated degradation confirmed by quenching tests.In XPS,EEMs analysis,and ECOSAR modeling further elucidate the surface reconstruction mechanism and intermediate toxicity reduction.This work establishes an atomic interface design paradigm that bridges catalytic innovation with green metallurgy applications,offering a sustainable solution for industrial wastewater remediation aligned with circular economy principles.展开更多
1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(inclu...1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(including Archean-Proterozoic migmatite,gneiss,schists and Pan-African “Older Granites”),Mesozoic alkaline ring complexes(“Younger Granites”) and sedimentary basins(Yang QD et al.,2023;Fig.1a).“Older Granites” are part of the Pan-African mobile belt;“Younger Granites” has significant peralkaline characteristics.“Younger Granites” has a wide distribution in the north-central region of Nigeria,including areas such as Kano,Jos-Bauchi,Mada,and Nasarawa,and the emplacement age gradually decreases from north to south from 213 Ma(Dutse complex) to 141 Ma(Afu complex)(Amuda AK et al.,2021).展开更多
The large-scale application of water electrolysis for H_(2) production is hindered by the sluggish kinetics of the anodic oxygen evolution reaction(OER).To improve the efficiency of water electrolyzers,numerous effort...The large-scale application of water electrolysis for H_(2) production is hindered by the sluggish kinetics of the anodic oxygen evolution reaction(OER).To improve the efficiency of water electrolyzers,numerous efforts have been devoted to developing robust OER catalysts.Among them,Ni-based materials have been identified as state-of-the-art catalysts in alkaline conditions due to their high catalytic activity[1,2].During OER,these catalysts can undergo surface reconstruction and form(oxy)hydroxide species on the surface,which is the real active phase and its chemistry determines the OER performance[3].展开更多
基金supported by the National Key Research and Development Program of China(No.2020YFC1908702)the National Natural Science Foundation of China(No.52131002)+1 种基金the Science and Technology Commission of Shanghai Municipality(No.22dz1209200)China Three Gorges Corporation(No.202403018).
文摘High ammonia-nitrogen digestate has become a key bottleneck limiting the anaerobic digestion of organic solid waste.Vacuum ammonia stripping can simultaneously remove and recover ammonia nitrogen,which has attracted a lot of attention in recent years.To investigate the parameter effects on the efficiency and mass transfer,five combination conditions(53℃ 15 kPa,60°C 20 kPa,65°C 25 kPa,72°C 35 kPa,and 81°C 50 kPa)were conducted for ammonia stripping of sludge digestate.The results showed that 80%of ammonia nitrogen was stripped in 45 min for all experimental groups,but the ammonia transfer coefficient varied under different conditions,which increased with the rising of boiling point temperature,and reached the maximum value(39.0 mm/hr)at 81°C 50 kPa.The ammonia nitrogen removal efficiency was more than 80%for 30 min vacuum stripping after adjusting the initial pH to above 9.5,and adjustment of the initial alkalinity also affects the pH value of liquid digestate.It was found that pH and alkalinity are the key factors influencing the ammonia nitrogen dissociation and removal efficiency,while temperature and vacuum mainly affect the ammonia nitrogen mass transfer and removal velocity.In terms of the mechanism of vacuum ammonia stripping,it underwent alkalinity destruction,pH enhancement,ammonia nitrogen dissociation,and free ammonia removal.In this study,two-stage experiments of alkalinity destruction and ammonia removal were also carried out,which showed that the two-stage configuration was beneficial for ammonia removal.It provides a theoretical basis and practical technology for the vacuum ammonia stripping from liquid digestate of organic solid waste.
基金funded by the National Natural Science Foundation of China(22478632)Key Scientific and Technological Project of Henan Province(242102321032).
文摘Continuous-flow upgrading of pentaerythritol synthesis technology via base-catalyzed aldol and Cannizzaro reactions of formaldehyde and acetaldehyde faces the challenge of effectively controlling the critical side reaction of hydroxymethyl acetaldehyde(HA)to the acrolein intermediate.Here,we first identified the forms of industrial formaldehyde as methane diol that easily converts to the alkaline formaldehyde under alkaline(NaOH)environment.The carbonyl group of alkaline formaldehyde induces deprotonation of acetaldehyde instead of the recognized base-hydroxyl group-induced deprotonation,and it needs to overcome only 18.31 kcal·mol^(-1)(1 kcal=4.186 kJ)energy barrier to form key intermediates of HA.The sodium solvation cage formed by NaOH hexa-coordinated formaldehyde effectively inhibits the alkalinity,thus contributing to a high energy barrier(46.21 kcal·mol^(-1))to unwanted acrolein formation.In addition,the solvation cage gradually opens to increase the alkalinity with the consumption of formaldehyde,thus facilitating the subsequent Cannizzaro reaction(to overcome 11.77 kcal·mol^(-1)).In comparison,strong alkalinity promotes the formation of acrolein(36.65 kcal·mol^(-1))to initiate the acetal side reaction,while weak alkalinity reduces the possibility of the Cannizzaro reaction(to overcome 20.44 kcal·mol^(-1)).This theoretically reveals the importance of the segmented feeding of weak and strong bases to successively control the aldol reaction and Cannizzaro reaction,and the combination of Na_(2)CO_(3) or HCOONa with NaOH improves the pentaerythritol yield by 7%to 13%compared to that of NaOH alone(70%yield)within 1 min at a throughput of 155.7 ml·min^(-1).
基金supported by the National Key Research and Development Program of China (2022YFE0138900)the “Scientific and Technical Innovation Action Plan” Basic Research Field of Shanghai Science and Technology Committee (19JC1410500)。
文摘Ion-solvaing membranes(ISMs)have received extensive attention in recent years as a key component in electrochemical energy conversion and storage devices.This article provides an overview of structural composition,performance advan-tages,research progress,ion conduction mechanism and existing issues of ISMs,primarily classifying them according to the matrix structure.A detailed analysis of performance enhancement methods,key performance indicators of ISMs and performance influencing factors is also presented.The article contributes to further optimizing the design and application of ion-solvation membranes,providing theoretical support for the development of fields such as hydrogen production through electrolysis of water and electrochemical energy in the future.
文摘Homret Ghannam alkali feldspar granite(HGAFG)in the central Eastern Desert(CED)of Egypt represents a distinctive example of late Neoproterozoic magmatism in the Arabian-Nubian Shield(ANS).This study integrates field observations,petrography,mineral chemistry(EMPA),and whole-rock geochemistry to investigate its petrogenesis,geodynamic evolution,and rare-metal potential.HGAFG comprises two cogenetic varieties,alkali feldspar granite and riebeckite-bearing granite,hosting rare-metal minerals such as zircon,fluorite,columbite and apatite.HGAFG exhibits diagnostic A-type geochemical characteristics,including high SiO₂contents(73.81-77.86 wt%),metaluminous to mildly peralkaline composition(ASI:0.92-1.03),enrichment in HFSE(Zr≈791.80 ppm,Nb≈68.12 ppm,Y≈90.81 ppm)andΣREE(103.40-475.57 ppm),and pronounced negative Eu anomalies(Eu/Eu^(*)=0.07-0.20).Zircon saturation thermometry yields high crystallization temperatures(TZr≈908.87℃)and low emplacement pressures(1.46 kbar)under reducing conditions(ƒO_(2)≈−11.5).The mineralogical and geochemical results reveal that HGAFG originated from a hybrid,fluorine-rich magma generated by anatexis of lower crust,followed by extensive fractional crystallization,during late post-collisional extension associated with lithospheric delamination.The reduced nature and fluorine enrichment of HGAFG magma promoted the mineralization of Nb-Ta-REE phases,highlighting its significance as a fertile,high-temperature product of the terminal magmatic stage in ANS evolution.
基金supported by the Natural Science Foundation of Shanghai(No.24ZR1419600).
文摘Plant-related organic compound(PROC)may interact with redox-active metals like iron while they are present in soil or aquatic environment,but their effects on the photoreduction of Fe(III)remain largely unexplored.This study investigates the photochemical behavior of Fe(III)-PROC complexes using alkaline lignin(AL),betaine hydrochloride(BH),and phytic acid(PA)as representative proxies for PROC.The reductive agent AL demonstrated the ability to directly reduce Fe(III)to Fe(II).In contrast,BH,being unable to form strong complexes with Fe(III),was able to quench·OH,thereby resulting in a shift of the redox equilibrium towards Fe(II).PA exhibited a strong binding affinity for Fe(III),effectively inhibiting its photoreduction.Electron paramagnetic resonance(EPR)analysis,utilizing 5,5-dimethyl-1-pyrroline-N-oxide(DMPO)as a spin trap,revealed that the DMPO-OH signal detected in photolyzed Fe(III)-PROC solutions originated from various pathways.Specifically,uncomplexed Fe(III)in AL or BH solutions was shown to oxidize DMPO directly,leading to the formation of a false DMPO-OH adduct.The addition of ethanol to the photolyzed Fe(III)-AL and Fe(III)-BH systems resulted in the generation of the DMPO-CH(CH_(3))OH adduct,thereby confirming the presence of authentic·OH in these systems.The photolysis of the Fe(III)-PA complex may proceed via a photodissociation mechanism,where the resulting loosely bound Fe(III)can oxidize DMPO,followed by a nucleophilic attack from water.This research highlights the multifaceted roles of PROC in facilitating the redox cycling of iron within soil and aquatic ecosystems.
基金funding enabled and organized by CAUL and its Member Institutionsby COMSTEQ-TWAS research grant 2018(18-268 RG/EAS/AS_C)。
文摘Examining carbonate dissolution kinetics at mineral-water interface is crucial to understand numerous environmental and geochemical processes,including global carbon cycling,CO_(2)sequestration in deep geological reservoirs,and trace elements release in terrestrial and aquatic environments.Here we explored the effect of circumneutral to alkaline pH solutions(pH 6-11)on dissolution kinetics of pure dolomite and Ca and Mg release stoichiometry in flow-through reactor experiments at 25±1℃.Results revealed that the dolomite dissolution rates obtained from effluent Ca and Mg concentrations(R_(Ca)and R_(Mg)in mol/cm^(2)/s)were dependent on input solution pH and HCO_(3)^(-)log activity.The pH dependence of dissolution rates showed two distinct trends,i.e.,at circumneutral pH ranging between 6 and 8,the dissolution rate decreased with increasing pH,with minimum rate at pH 8.While in the highly alkaline pH range(pH 9-11),the dolomite dissolution rate increased with an increasing pH.Irrespective of the input pH,the dolomite dissolution rates indicated a reverse relationship with HCO_(3)^(-)log activity,with the lowest dissolution rate(R Ca=3.80×10^(-12)mol/cm^(2)/s)at pH 8 where HCO_(3)^(-)log activity attained the highest value(-3.957).The lower R Ca and R Mg obtained at pH 8 compared to all the other pH could possibly be attributed to an inhibition caused by high HCO_(3)^(-)log activity in solution at this pH.Dolomite dissolution rates were non-stoichiometric at all the experimental pH values,showing higher preferential Ca over Mg release(R_(Ca)>R_(Mg))whereas an opposite trend was observed at pH 8,with R_(Ca)<R_(Mg)at the steady state.Saturation index values calculated using geochemical speciation modelling were positive for Mg-bearing minerals(brucite,dolomite,artinite)at alkaline pH of 10-11,indicating favourable conditions for their precipitation under studied conditions.This study provides insights on the significance of log ion activities of HCO_(3)^(-)and Me-OH^(+)under varying pH for elucidating the dissolution mechanism of dolomite in circumneutral to alkaline aqueous environments.
基金supported by the National Key R&D Program of China(2022YFA1503002,2022YFA1503003)the National Natural Science Foundation of China(22271081)+2 种基金the Natural Science Foundation of Heilongjiang Province(PL2024B017)the Postdoctoral Science Foundation of Heilongjiang Province(LBH-Z22240)the Heilongjiang University Excellent Youth Foundation。
文摘NiMo-based catalysts show significant potential for the hydrogen evolution reaction(HER).Optimizing the electronic structure and enhancing mass transfer are two critical factors for improving catalytic performance,but they remain significant challenges.Herein,we present a route for synthesizing two-dimensional(2D)porous Mo_(2)N-Ni heterojunction nanosheets with tuned Ni-Mo ratio for enhanced alkaline HER performance.A precursor can be easily synthesized by assembling polyoxometalate clusters(PMo_(12))with layered hydroxy oxides(Ni(OH)_(2)).It is found that the interaction between PMo_(12)and Ni(OH)_(2)can effectively protect the particles from significant agglomeration during pyrolysis,resulting in the formation of 2D porous sheets composed of small Mo_(2)N-Ni units.The transfer of electrons from Ni to Mo_(2)N results in the redistribution of electrons at the heterojunction,optimizing the adsorption and desorption of intermediates.Moreover,the 2D porous structure comprised of small particles enhances mass transfer,thereby reducing the impedance of the catalyst.Consequently,the catalyst with an optimized Mo/Ni ratio exhibits an overpotential of 19 mV at 10 mA cm^(-2),being comparable to that of commercial Pt/C catalyst.The anion exchange membrane(AEM)electrolyzer,consisting of optimized Mo_(2)N-Ni and NiFe-LDH,achieves a current density of 500 mA cm^(-2)at 1.80 V and can operate stably for 300 h.This assembly method offers an effective strategy for the large-scale preparation of efficient catalysts.
基金supported by Yunnan Major Scientific and Technological Projects(Grant No.202402AB080004)Yunnan Provincial Education Department Universities Serve Key Industry Science and Technology Projects(Grant No:FWCY-BSPY2024043)+1 种基金Top Innovative Talents for Graduate Students of KUST(Grant No:CA24163M116A)Analysis and Testing Fund of KUST(Grant No:2024P20233102006).The authors extend their gratitude to Mr.Kong Qingyuan from Scientific Compass(www.shiyanjia.com)for providing invaluable assistance with scientific research.
文摘The accumulation of refractory organics in Bayer liquor(pH 14.4)critically compromises aluminum production efficiency and product quality,necessitating sustainable remediation strategies.Herein,we develop an ultrasonic-driven catalytic ozonation system with dynamically reconstructed CuO/Cu2O heterointerfaces,achieving unprecedented efficiency in extreme alkaline wastewater treatment.Atomic-scale interface engineering endows the catalyst with hydrophilicity(contact angle:6.1°)and 3.8–4.3 times higher oxygen vacancy density compared to single-phase catalysts.These properties facilitate efficient interfacial interactions with Bayer liquor and enable superior ozone activation through synergistic Cu(I)/Cu(II)redox cycling across the heterointerface.This interfacial synergy reduces ozone adsorption energy from 5.46 eV(Cu_(2)O)to 1.48 eV,driving the generation of reactive oxygen species(ROS)via low-energy pathways.Under optimized conditions,the system achieves 57.82%TOC removal within 1.5 h with 2.3-fold faster kinetics than ozone–alone processes,while improving energy efficiency by 1.82–3.22 times per kWh over conventional thermal oxidation.Remarkable stability is demonstrated through 80.21%activity retention after 6 cycles,attributed to surface energy minimization(0.61 J m^(−2)),alongside 67.91%hydroxyl radical(•OH)-mediated degradation confirmed by quenching tests.In XPS,EEMs analysis,and ECOSAR modeling further elucidate the surface reconstruction mechanism and intermediate toxicity reduction.This work establishes an atomic interface design paradigm that bridges catalytic innovation with green metallurgy applications,offering a sustainable solution for industrial wastewater remediation aligned with circular economy principles.
基金funded by the projects of Tianjin North China Geological Exploration Bureau (HK2023–B01,HK2022–B08)China Geological Survey (DD20230576,DD20201152)。
文摘1.Objective Nigeria lies between the West African Craton and the Congo Craton,south of the Tuareg Shield(Ogunmola JK et al.,2015).The Nasarawa pegmatite field mainly comprises of the Precambrian Basement Complex(including Archean-Proterozoic migmatite,gneiss,schists and Pan-African “Older Granites”),Mesozoic alkaline ring complexes(“Younger Granites”) and sedimentary basins(Yang QD et al.,2023;Fig.1a).“Older Granites” are part of the Pan-African mobile belt;“Younger Granites” has significant peralkaline characteristics.“Younger Granites” has a wide distribution in the north-central region of Nigeria,including areas such as Kano,Jos-Bauchi,Mada,and Nasarawa,and the emplacement age gradually decreases from north to south from 213 Ma(Dutse complex) to 141 Ma(Afu complex)(Amuda AK et al.,2021).
文摘The large-scale application of water electrolysis for H_(2) production is hindered by the sluggish kinetics of the anodic oxygen evolution reaction(OER).To improve the efficiency of water electrolyzers,numerous efforts have been devoted to developing robust OER catalysts.Among them,Ni-based materials have been identified as state-of-the-art catalysts in alkaline conditions due to their high catalytic activity[1,2].During OER,these catalysts can undergo surface reconstruction and form(oxy)hydroxide species on the surface,which is the real active phase and its chemistry determines the OER performance[3].
