Enzyme-Induced Carbonate Precipitation(EICP)is an innovative technique to improve soil strength and reduce permeability.However,the use of EICP for reinforcing underwater sand beds remains largely unexplored.To advanc...Enzyme-Induced Carbonate Precipitation(EICP)is an innovative technique to improve soil strength and reduce permeability.However,the use of EICP for reinforcing underwater sand beds remains largely unexplored.To advance EICP implementation in various geotechnical applications,this paper develops a model box system to investigate the effectiveness of the EICP technique in reinforcing underwater sand beds.An"injection-extraction"system is designed to facilitate the flow of the EICP solution through underwater sand layers.Key parameters,including conductivity,pH,and Ca^(2+)concentration of the solution,are measured and analyzed.Electrical resistivity tomography(ERT)is utilized to evaluate the reinforcement effect in the underwater sand bed.The permeability of the model is tested to verify the feasibility of EICP technology for strengthening underwater sands.Furthermore,scanning electron microscope(SEM)is performed to investigate the growth mechanisms of calcium carbonate(CaCO_(3))crystals.The results show that the permeability of the model decreases from 1.28×10^(-2)m/s to 9.66×10^(-5)m/s,representing a reduction of approximately three orders of magnitude.This verifies that the EICP technology can greatly reduce the permeability of underwater sand beds.With increasing grouting cycles,the resistivity of the underwater sand initially decreases and then increases.This variation in sand resistivity is significantly influenced by the ion concentration in the solution,resulting in marked differences in resistivity at various depths and positions within the sand.The findings from this study offer a theoretical basis for the application of EICP technology in reinforcing seabed foundations and supporting marine infrastructure such as offshore pipelines,wind turbines,and oil platforms.展开更多
While oceanic and coastal acidification has gained increased attention,long-term pH trends and their drivers in large freshwater systems remain poorly understood.The Laurentian Great Lakes are the world’s largest fre...While oceanic and coastal acidification has gained increased attention,long-term pH trends and their drivers in large freshwater systems remain poorly understood.The Laurentian Great Lakes are the world’s largest freshwater system,and in many ways resemble marine ecosystems.However,unlike the open ocean and coastal waters where pH has declined due to rising atmospheric CO_(2),no significant pH trends have been observed in the Laurentian Great Lakes,despite significant ecosystem changes driven partly by the invasion of dreissenid mussels.This study examined 41 years of field observations from Lake Michigan to investigate the long-term carbonate chemistry dynamics.Observational results revealed substantial declines in both total alkalinity(TA)and dissolved inorganic carbon(DIC)over the four decades.Mussel shell calcification emerged as the primary mechanism behind these declines,accounting for 97%and 47%of the observed changes in TA and DIC,respectively,lowering water column pH by 0.24 units.Elevated carbon accumulation in soft mussel tissues,coupled with long-term changes in the air-water pCO_(2)gradient during summer,significantly contributed to long-term DIC variations,explaining 18%and 28%of the lake-wide DIC loss.These two mechanisms also resulted in an overall pH increase of 0.09 and 0.12 units,largely offsetting the calcification-driven pH decrease.These findings bridge a gap in acidification research for large freshwater systems and provide valuable insights for comprehensive lake-wide management strategies.展开更多
Microbially induced calcium carbonate precipitation(MICP)is an eco-friendly technology for soil improvement.Although numerous experiments have been conducted to solidify sand foundations using MICP,the mechanisms by w...Microbially induced calcium carbonate precipitation(MICP)is an eco-friendly technology for soil improvement.Although numerous experiments have been conducted to solidify sand foundations using MICP,the mechanisms by which grain interfacial morphologies influencethe MICP process remain unclear.This study utilized 3D-printed flowcells with different boundary morphologies to investigate the effects of interfacial morphologies on the MICP process.CaCO_(3)precipitation characteristics were investigated through microscopic observation and image quantificationanalysis.The results indicate that low flowvelocities near the interface promote bacterial accumulation due to reduced hydrodynamic shear forces.Rough interfaces,compared to smooth ones,enhance bacterial adsorption owing to the larger regions of low flowvelocity,increased surface area,and the formation of local eddies,which promote greater CaCO_(3)precipitation.Compared to the regions away from the interface,a higher abundance of small CaCO_(3)crystals is observed near the interface because of the high urease activity from bacteria and the reduced shear-induced entrainment due to the low flowvelocity.Besides,larger crystals also preferentially precipitate in proximity to interfaces as the low flowvelocity enhances crystal growth according to the particle attachment theory.The presence of rough interfaces further reduces flowvelocities,leading to the precipitation of larger and more densely packed CaCO_(3)crystals.Therefore,rough interfaces promote the microbially induced calcium carbonate precipitation.This work is expected to enhance the understanding of microbially induced calcium carbonate precipitation characteristics on solid surfaces such as soil grains and contribute to the optimization of MICP applications.展开更多
In recent years,the addition of probiotics into non-dairy beverages has gained popularity.Probiotics offer a wider range of options for individuals who are sensitive to dairy products.Incorporating probiotics into wid...In recent years,the addition of probiotics into non-dairy beverages has gained popularity.Probiotics offer a wider range of options for individuals who are sensitive to dairy products.Incorporating probiotics into widely consumed beverages like carbonated soft drinks poses a notable challenge due to the detrimental impact of acidic pH.Herein,results demonstrate that chitosan-coated alginate/gellan gum microcapsules can enhance the viability of probiotics within carbonated soft drinks.The probiotics,Lactobacillus casei,are encapsulated in microcapsules and exposed to Pepsi,Fanta Strawberry,Sprite,and A&W Root Beer under 4 and 25℃for 60 days and simulated gastrointestinal tract.Microcapsules greatly improve the viability of adding probiotics in different beverages under simulated gastrointestinal tract.The probiotics had a gradual release from microcapsules,reaching maximum release within initial 2 h of simulated intestinal phase.During 4℃storage compared to storage at 25℃,it was found that the number of surviving cells is more than the recommended minimum(10^(6)CFU/g)at the end of the storage.The pH and soluble solids content of beverages containing microcapsules also signify little change.This work shows that the chitosan-coated alginate/gellan microcapsules have the potential to be used as protective microcapsules for probiotics in carbonated soft drinks.展开更多
Carbonated silicate melts transport oxidized carbon from the deep to shallow mantle,and thus play an important role in the deep carbon cycle.However,it is unclear how carbonated silicate melts are formed.Here,we repor...Carbonated silicate melts transport oxidized carbon from the deep to shallow mantle,and thus play an important role in the deep carbon cycle.However,it is unclear how carbonated silicate melts are formed.Here,we report whole-rock major and trace element,and Mg-Zn-Fe isotope,and in situ olivine and clinopyroxene Mg isotope data for peridotites and pyroxenites in Cenozoic alkaline basalts from Shulan and Yitong,Northeast China,to reveal the formation mechanisms of carbonated silicate melts.As residues of the primitive mantle,most of the Shulan and Yitong(spinel)harzburgite and lherzolite have relatively lower δ26Mg and higher δ66Zn than the mantle values,and show LREE-enriched patterns.These features indicate that these peridotites have been modified by carbonated silicate melt,transforming them into carbonated peridotites.The Shulan websterites exhibit metasomatic textures,and most of their whole-rock and in situ δ26Mg values are lower than the mantle values,which also supports the presence of a carbonated lithospheric mantle.The Yitong cumulate orthopyroxenites,representing silica-rich melts,have lower δ26Mg and higher δ66Zn values than mantle peridotites,implying that recycled carbonate has been involved in these silica-rich melts.The Yitong cumulate wehrlites and(olivine)websterites display major element compositions similar to those of carbonated peridotite melts,coupled with low whole-rock and clinopyroxene δ26Mg values,high δ66Zn and δ57Fe values,indicating the occurrence of carbonated silicate melts.The transition from orthopyroxenites to(olivine)websterites is marked by the decreasing of their whole-rock δ26Mg,δ57Fe values and Zn/Fe ratios and increasing of their δ66Zn values,along with decreasing of their crystallization temperatures,suggesting that silica-rich melts were gradually transformed into carbonated silicate melts via continuous interaction with carbonated peridotite.Our findings demonstrate that silica-rich melts from the stagnant slab can extract carbon from pre-existing carbonated mantle within the big mantle wedge.展开更多
The recovery of rare earths from industrial rare earth leaching solution is typically achieved through the ammonium carbonate precipitation method,which presents challenges in terms of prolonged production cycle and a...The recovery of rare earths from industrial rare earth leaching solution is typically achieved through the ammonium carbonate precipitation method,which presents challenges in terms of prolonged production cycle and ammonia nitrogen pollution.The present study explored the synthesis of crystalline yttrium carbonate in a sodium carbonate system,employing a conventional mother liquor derived from yttrium chloride.The growth of yttrium carbonate was explored through the lens of density functional theory(DFT)calculations,unveiling a novel perspective on its formation mechanism.The synthesized yttrium carbonate demonstrates enhanced crystallinity,with a D50value of 19.75μm achieved under reaction conditions comprising a temperature of 60℃,stirring rate of 200 r/min,feeding rate of 4 mL/min,and aging time of 30 h.The molar ratio for precipitation is set at 1.6:1.The morphology of yttrium carbonate undergoes a transition from needle-like structures to sheet-like formations,ultimately culminating in the formation of spherical aggregates.The variation in surface energy among distinct crystal planes and CO_(3)^(2-)configurations within crystal cells accounts for this phenomenon.The DFT calculations unveil a progression of growth and trans formation in yttrium carbonate,commencing from a one-dimensional configuration and culminating in a multidimensional morphology.展开更多
To solve the problem of ammonia wastewater pollution generated from preparing rare earth carbonate using the ammonium bicarbonate precipitation method,an eco-friendly precipitant,magnesium bicarbonate,was used to prep...To solve the problem of ammonia wastewater pollution generated from preparing rare earth carbonate using the ammonium bicarbonate precipitation method,an eco-friendly precipitant,magnesium bicarbonate,was used to prepare lanthanum cerium carbonate.The lanthanum cerium sulfate solution obtained from the smelting and separation of Baotou mixed rare earth ore was used as the raw material.The influence of pH on the content of impurities,including SO^(2-)_(4)and magnesium,and the existing states of SO^(2-)_(4)n lanthanum cerium carbonate products,as well as the thermal decomposition behavior of the products,were deeply explored.SO^(2-)_(4)mainly exists in the form of rare earth sulfate complex salts in lanthanum cerium carbonate products.The fo rmation of the salts can be effectively avoided by adjusting the pH of the precipitation process.Then the content of SO^(2-)_(4)in the product is controlled.When the pH ranges from 6.00 to 7.12,the content of SO^(2-)_(4)in the product ranges from 0.42 wt%to 0.99 wt%.The content of MgO is lower than 0.04 wt%.Both contents meet the requirements of the national standard GB/T 16479-2020.In this study,lanthanum cerium carbonate products with low-content SO^(2-)_(4)were prepared.In addition,the existing states of SO^(2-)_(4)in the products are revealed.The research provides a new method for controlling the impurity content in preparing lanthanum cerium carbonate.展开更多
Transition metal-carbonate interfaces often act as active sites in heterogeneous catalytic reactions.The interface between transition metal and metal carbonate exhibits a dynamic equilibrium during the CO_(2)hydrogena...Transition metal-carbonate interfaces often act as active sites in heterogeneous catalytic reactions.The interface between transition metal and metal carbonate exhibits a dynamic equilibrium during the CO_(2)hydrogenation reaction,involving surface carbonate hydrogenation and CO_(2)chemisorption.Nonetheless,there have been few reports on engineering the activity of the interface between transition metal and alkaline earth metal carbonate for catalytic CO_(2)conversion.This work demonstrated that the incorporation of CaH_(2)in Ni/CaCO_(3)enhances the CO_(2)methanation activity of the catalysts.The CO_(2)conversion for Ni/CaH_(2)-CaCO_(3)reached 68.5%at 400°C,which was much higher than that of the Ni/CaCO_(3)(31.6%) and Ni/CaH_(2)-CaO (42.4%) catalysts.Furthermore,the Ni/CaH_(2)-CaCO_(3)catalysts remained stable during the stability test for 24 h at 400°C and 8 bar.Our research revealed that CaH_(2)played a crucial role in promoting the activity of the Ni-carbonate interface for CO_(2)methanation.CaH_(2)could modify the electronic structure of Ni and tune the structural properties of CaCO_(3)to generate medium basic sites (OH groups),which are favorable for the activation of H2and CO_(2).In-situ Fourier transform infrared spectroscopy (FTIR) analysis combined with density functional theory calculations demonstrated that CO_(2)activation occurs at the hydroxyl group (OH) on the CaH_(2)-modified Ni-carbonate surface,leading to the formation of CO_(3)H*species.Furthermore,our study has confirmed that CO_(2)methanation over the Ni/CaH_(2)-CaCO_(3)catalysts proceeds via the formate pathway.展开更多
This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistr...This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistry experiment and production test data,to systematically explore the control mechanisms of structure and fluid on the scale,quality,effectiveness and connectivity of ultra-deep fault-controlled carbonate fractured-vuggy reservoirs in the Tarim Basin.The results show that reservoir scale is influenced by strike-slip fault scale,structural position,and mechanical stratigraphy.Larger faults tend to correspond to larger reservoir scales.The reservoir scale of contractional overlaps is larger than that of extensional overlaps,while pure strike-slip segments are small.The reservoir scale is enhanced at fault intersection,bend,and tip segments.Vertically,the heterogeneity of reservoir development is controlled by mechanical stratigraphy,with strata of higher brittleness indices being more conducive to the development of fractured-vuggy reservoirs.Multiple phases of strike-slip fault activity and fluid alterations contribute to fractured-vuggy reservoir effectiveness evolution and heterogeneity.Meteoric water activity during the Late Caledonian to Early Hercynian period was the primary phase of fractured-vuggy reservoir formation.Hydrothermal activity in the Late Hercynian period further intensified the heterogeneity of effective reservoir space distribution.The study also reveals that fractured-vuggy reservoir connectivity is influenced by strike-slip fault structural position and present in-situ stress field.The reservoir connectivity of extensional overlaps is larger than that of pure strike-slip segments,while contractional overlaps show worse reservoir connectivity.Additionally,fractured-vuggy reservoirs controlled by strike-slip faults that are nearly parallel to the present in-situ stress direction exhibit excellent connectivity.Overall,high-quality reservoirs are distributed at the fault intersection of extensional overlaps,the central zones of contractional overlaps,pinnate fault zones at intersection,bend,and tip segments of pure strike-slip segments.Vertically,they are concentrated in mechanical stratigraphy with high brittleness indices.展开更多
Magnesium alloy is a promising biodegradable metal material for hard tissue engineering.However,its high corrosion rate limits its application.In our previous study,we biomimetically deposited a calcium carbonate coat...Magnesium alloy is a promising biodegradable metal material for hard tissue engineering.However,its high corrosion rate limits its application.In our previous study,we biomimetically deposited a calcium carbonate coating on the surface of magnesium alloy using siloxane induction.This calcium carbonate coating demonstrated excellent in vitro biocompatibility and provided partial protection for the magnesium alloy substrate.In this study,we further enhanced the corrosion resistance of the calcium carbonate coating by treating it with stearic acid and its derivative,sodium stearate.Electrochemical corrosion tests revealed that the sodium stearate-treated calcium carbonate coating reduced the corrosion rate by two orders of magnitude.Additionally,in vitro biocompatibility assessments showed that while the biocompatibility of the sodium stearate-treated coating was slightly reduced,it remained acceptable compared to the magnesium substrate.This study builds on our previous work and offers a promising reinforcement strategy for degradable magnesium alloys in medical applications.展开更多
To address the challenges in studying the pore formation and evolution processes,and unclear preservation mechanisms of deep to ultra-deep carbonate rocks,a high-temperature and high-pressure visualization simulation ...To address the challenges in studying the pore formation and evolution processes,and unclear preservation mechanisms of deep to ultra-deep carbonate rocks,a high-temperature and high-pressure visualization simulation experimental device was developed for ultra-deep carbonate reservoirs.Carbonate rock samples from the Sichuan Basin and Tarim Basin were used to simulate the dissolution-precipitation process of deep to ultra-deep carbonate reservoirs in an analogous geological setting.This unit comprises four core modules:an ultra-high temperature,high pressure triaxial stress core holder module(temperature higher than 300°C,pressure higher than 150 MPa),a multi-stage continuous flow module with temperature-pressure regulation,an ultra-high temperature-pressure sapphire window cell and an in-situ high-temperature-pressure fluid property measurement module and real-time ultra-high temperature-pressure permeability detection module.The new experimental device was used for simulation experiment,the geological insights were obtained in three aspects.First,the pore-throat structure of carbonate is controlled by lithology and initial pore-throat structure,and fluid type,concentration and dissolution duration determine the degree of dissolution.The dissolution process exhibits two evolution patterns.The dissolution scale is positively correlated to the temperature and pressure,and the pore-forming peak period aligns well with the hydrocarbon generation peak period.Second,the dissolution potential of dolomite in an open flow system is greater than that of limestone,and secondary dissolved pores formed continuously are controlled by the type and concentration of acidic fluids and the initial physical properties.These pores predominantly distribute along pre-existing pore/fracture zones.Third,in a nearly closed diagenetic system,after the chemical reaction between acidic fluids and carbonate rock reaches saturation and dynamic equilibrium,the pore structure no longer changes,keeping pre-existing pores well-preserved.These findings have important guiding significance for the evaluation of pore-throat structure and development potential of deep to ultra-deep carbonate reservoirs,and the prediction of main controlling factors and distribution of high-quality carbonate reservoirs.展开更多
Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temper...Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.展开更多
The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated t...The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated to assess erosion depth,microstructure,phase migrations,and pore structure in various tunnel lining cement-based materials.Additionally,Ca^(2+)leaching was analyzed,and impact of Ca/Si molar ratio in hydration products on erosion resistance was discussed by thermodynamic calculations.The results indicate that carbonated water erosion caused rough and porous surface on specimens,with reduced portlandite and CaCO_(3) content,increased porosity,and an enlargement of pore size.The thermodynamic calculations indicate that the erosion is spontaneous,driven by physical dissolution and chemical reactions dominated by Gibbs free energy.And the erosion reactions proceed more spontaneously and extensively when Ca/Si molar ratio in hydration products was higher.Therefore,cement-based materials with higher portlandite content exhibit weaker erosion resistance.Model-building concrete,with C-S-H gel and portlandite as primary hydration products,has greater erosion susceptibility than shotcrete with ettringite as main hydration product.Moreover,adding silicon-rich mineral admixtures can enhance the erosion resistance.This research offers theory and tech insights to boost cement-based material resistance against carbonated water erosion in karst tunnel engineering.展开更多
Indoles and their derivatives are an important class of N-heterocycles.In this article,iridium-catalyzed annulation reactions of N-aryl-2-aminopyridines to synthesize indole derivatives are designed and developed,whic...Indoles and their derivatives are an important class of N-heterocycles.In this article,iridium-catalyzed annulation reactions of N-aryl-2-aminopyridines to synthesize indole derivatives are designed and developed,which utilize vinylene carbonate as a new C2 synthon.This protocol is expected to provide a facile and useful access to various indole derivatives.展开更多
A single component molybdenum catalyst was synthesized and its activity in the cycloaddition reaction of CO_(2)and epoxide was tested.The results show that the molybdenum catalysts exhibit high activity and a broad su...A single component molybdenum catalyst was synthesized and its activity in the cycloaddition reaction of CO_(2)and epoxide was tested.The results show that the molybdenum catalysts exhibit high activity and a broad substrate scope under the reaction conditions of 80℃and 0.5 MPa of CO_(2),solvent-free,and and no nucleophilic cocatalysts,affording a wide range of cyclic carbonates in yields of 42%~94%.The reaction mechanism was investigated using in situ infrared(in situ IR),high-resolution mass spectrometry(HRMS)and Fourier transform infrared spectroscopy(FT-IR).展开更多
Transformation of urea and glycerol to glycerol carbonate is an environmental friendly and economical process.Catalysts play an indispensable role in the process.Although many catalysts have been developed,the perform...Transformation of urea and glycerol to glycerol carbonate is an environmental friendly and economical process.Catalysts play an indispensable role in the process.Although many catalysts have been developed,the performance of the catalysts still cannot meet the needs of industrialization.In this paper,research progress of the homogeneous and heterogeneous catalysts of the reaction over the past 20 years were reviewed systematically.According to the types and active centers of catalysts,the catalysts were classified systematically and analyzed in detail.The typical reaction mechanisms were also summarized.The research and development direction of catalysts is made more explicit through systematic classification and mechanism analysis.The article reveals more novel catalysts have been designed and used for the reaction,such as mixed metal oxides with special structures,solid wastes and non-metallic materials.This work summarized the current state of research and prospected possible routes for design of novel catalysts.It is hoped that this review can provide some references for developing efficient catalysts.展开更多
Filtration is a prevalent treatment modality in the domain of wastewater management.Depending on the materials and properties of the filtration media,filtration can be classified into four main categories:microfiltrat...Filtration is a prevalent treatment modality in the domain of wastewater management.Depending on the materials and properties of the filtration media,filtration can be classified into four main categories:microfiltration,ultrafiltration,nanofiltration,and reverse osmosis.The present study focuses on the preparation of a novel porous CaCO_(3)microfiltration membrane,which is based on the microbial-induced calcium carbonate precipitation(MICP)biomineralization process.Initially,CaCO_(3) crystal particles with urease activity are prepared by controlling the MICP mineralization process.Secondary microbial mineralization is used to cement the loose calcium carbonate particles,forming a continuous porous solid CaCO_(3)membrane with certain mechanical strength.Filtration tests on bacterial cells,extracellular proteins,and polysaccharides show that the MICP-driven porous CaCO_(3) membrane effectively removes Escherichia coli,Brachybacterium sp.,and activated sludge,with removal rates of 99.998%,99.983%,and 99.996%,respectively.Compared to conventional filter paper,this porous CaCO_(3) membrane demonstrates superior capability in removing extracellular polymers(EPS).Furthermore,the CaCO_(3) microfiltration membrane prepared using the MICP process also exhibits ideal pore space,non-blocking characteristics,and high permeability.展开更多
The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick s...The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma.展开更多
Conversion and capture of carbon pollutants based on carbon dioxide to valuable green oil-field chemicals are target all over the world for controlling the global warming.The present article used new room temperature ...Conversion and capture of carbon pollutants based on carbon dioxide to valuable green oil-field chemicals are target all over the world for controlling the global warming.The present article used new room temperature amphiphilic imidazolium ionic liquids with superior surface activity in the aqueous solutions to convert carbon dioxide gas to superior amphiphilic calcium carbonate nanoparticles.In this respect,tetra-cationic ionic liquids 2-(4-dodecyldimethylamino)phenyl)-1,3-bis(3-dodecyldimethylammnonio)propyl)bromide-1-H-imidazol-3-ium acetate and 2-(4-hexyldimethylamino)phenyl)-1,3-bis(3-hexcyldimethylammnonio)propyl)bromide-1 H-imidazol-3-ium acetate were prepared.Their chemical structures,thermal as well as their carbon dioxide absorption/desorption characteristicswere evaluated.Theywere used as solvent and capping agent to synthesize calcium carbonate nanoparticles with controlled crystalline lattice,sizes,thermal properties and spherical surface morphologies.The prepared calcium carbonate nanoparticles were used as additives for the commercial water based drilling mud to improve their filter lose and rheology.The data confirm that the lower concentrations of 2-(4-dodecyldimethylamino)phenyl)-1,3-bis(3-dodecyldimethylammnonio)propyl)bromide-1-H-imidazol-3-ium acetate achieved lower seawater filter lose and improved viscosities.展开更多
The synthesis of polyurethanes(PUs)from the reaction of low molecular weight poly(ethylene carbonate)diol(PECD)is rarely investigated.This work reports a novel PU with excellent mechanical properties from the solution...The synthesis of polyurethanes(PUs)from the reaction of low molecular weight poly(ethylene carbonate)diol(PECD)is rarely investigated.This work reports a novel PU with excellent mechanical properties from the solution polymerization of 4,4-diphenylmethane diisocyanate(MDI)with PECD that was derived from the copolymerization of carbon dioxide(CO_(2))and ethylene oxide(EO).The tensile strength,the elongation at break and 300%constant tensile strength of the PECD-PU were up to 66±2 MPa,880%±50%and 13 MPa,respectively,higher than the control PUs from the reaction of MDI with commercial polyethers or polyesters.The PECD-PU with high CO_(2) carbonate content exhibited good solvent resistance and chemical stability.Of importance,the mechanical properties and chemical resistance of PECD-PU were significantly enhanced with the increasing content of CO_(2),i.e.,the carbonate unit in PECD.This work provides comprehensive properties of PECD-derived PUs,indicating that PECD is a competitive precursor for the preparation of PU and has broad application prospects.展开更多
基金supported by the National Youth Top-notch Talent Support Program of China(Grant No.00389335)the National Natural Science Foundation of China(Grant No.52378392)+1 种基金the“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province(Grant No.00387088)supports are gratefully acknowledged.
文摘Enzyme-Induced Carbonate Precipitation(EICP)is an innovative technique to improve soil strength and reduce permeability.However,the use of EICP for reinforcing underwater sand beds remains largely unexplored.To advance EICP implementation in various geotechnical applications,this paper develops a model box system to investigate the effectiveness of the EICP technique in reinforcing underwater sand beds.An"injection-extraction"system is designed to facilitate the flow of the EICP solution through underwater sand layers.Key parameters,including conductivity,pH,and Ca^(2+)concentration of the solution,are measured and analyzed.Electrical resistivity tomography(ERT)is utilized to evaluate the reinforcement effect in the underwater sand bed.The permeability of the model is tested to verify the feasibility of EICP technology for strengthening underwater sands.Furthermore,scanning electron microscope(SEM)is performed to investigate the growth mechanisms of calcium carbonate(CaCO_(3))crystals.The results show that the permeability of the model decreases from 1.28×10^(-2)m/s to 9.66×10^(-5)m/s,representing a reduction of approximately three orders of magnitude.This verifies that the EICP technology can greatly reduce the permeability of underwater sand beds.With increasing grouting cycles,the resistivity of the underwater sand initially decreases and then increases.This variation in sand resistivity is significantly influenced by the ion concentration in the solution,resulting in marked differences in resistivity at various depths and positions within the sand.The findings from this study offer a theoretical basis for the application of EICP technology in reinforcing seabed foundations and supporting marine infrastructure such as offshore pipelines,wind turbines,and oil platforms.
基金Supported by the National Natural Science Foundation of China(No.43277051)the Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education(No.B230203006).
文摘While oceanic and coastal acidification has gained increased attention,long-term pH trends and their drivers in large freshwater systems remain poorly understood.The Laurentian Great Lakes are the world’s largest freshwater system,and in many ways resemble marine ecosystems.However,unlike the open ocean and coastal waters where pH has declined due to rising atmospheric CO_(2),no significant pH trends have been observed in the Laurentian Great Lakes,despite significant ecosystem changes driven partly by the invasion of dreissenid mussels.This study examined 41 years of field observations from Lake Michigan to investigate the long-term carbonate chemistry dynamics.Observational results revealed substantial declines in both total alkalinity(TA)and dissolved inorganic carbon(DIC)over the four decades.Mussel shell calcification emerged as the primary mechanism behind these declines,accounting for 97%and 47%of the observed changes in TA and DIC,respectively,lowering water column pH by 0.24 units.Elevated carbon accumulation in soft mussel tissues,coupled with long-term changes in the air-water pCO_(2)gradient during summer,significantly contributed to long-term DIC variations,explaining 18%and 28%of the lake-wide DIC loss.These two mechanisms also resulted in an overall pH increase of 0.09 and 0.12 units,largely offsetting the calcification-driven pH decrease.These findings bridge a gap in acidification research for large freshwater systems and provide valuable insights for comprehensive lake-wide management strategies.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3707900)National Natural Science Foundation of China(Grant No.42230710,42525201)Key task project for joint research and development of the Yangtze River Delta Science and Technology Innovation Community(Grant No.2022CSJGG1200).
文摘Microbially induced calcium carbonate precipitation(MICP)is an eco-friendly technology for soil improvement.Although numerous experiments have been conducted to solidify sand foundations using MICP,the mechanisms by which grain interfacial morphologies influencethe MICP process remain unclear.This study utilized 3D-printed flowcells with different boundary morphologies to investigate the effects of interfacial morphologies on the MICP process.CaCO_(3)precipitation characteristics were investigated through microscopic observation and image quantificationanalysis.The results indicate that low flowvelocities near the interface promote bacterial accumulation due to reduced hydrodynamic shear forces.Rough interfaces,compared to smooth ones,enhance bacterial adsorption owing to the larger regions of low flowvelocity,increased surface area,and the formation of local eddies,which promote greater CaCO_(3)precipitation.Compared to the regions away from the interface,a higher abundance of small CaCO_(3)crystals is observed near the interface because of the high urease activity from bacteria and the reduced shear-induced entrainment due to the low flowvelocity.Besides,larger crystals also preferentially precipitate in proximity to interfaces as the low flowvelocity enhances crystal growth according to the particle attachment theory.The presence of rough interfaces further reduces flowvelocities,leading to the precipitation of larger and more densely packed CaCO_(3)crystals.Therefore,rough interfaces promote the microbially induced calcium carbonate precipitation.This work is expected to enhance the understanding of microbially induced calcium carbonate precipitation characteristics on solid surfaces such as soil grains and contribute to the optimization of MICP applications.
基金Chulalongkorn University and the National Science and Technology Development Agency(NSTDA)for providing the Chulalongkorn University-NSTDA Doctoral Scholarship,which funded this articlesupport from the 90~(th)Anniversary of Chulalongkorn University Scholarship under the Ratchadaphisek Somphot Endowment Fund。
文摘In recent years,the addition of probiotics into non-dairy beverages has gained popularity.Probiotics offer a wider range of options for individuals who are sensitive to dairy products.Incorporating probiotics into widely consumed beverages like carbonated soft drinks poses a notable challenge due to the detrimental impact of acidic pH.Herein,results demonstrate that chitosan-coated alginate/gellan gum microcapsules can enhance the viability of probiotics within carbonated soft drinks.The probiotics,Lactobacillus casei,are encapsulated in microcapsules and exposed to Pepsi,Fanta Strawberry,Sprite,and A&W Root Beer under 4 and 25℃for 60 days and simulated gastrointestinal tract.Microcapsules greatly improve the viability of adding probiotics in different beverages under simulated gastrointestinal tract.The probiotics had a gradual release from microcapsules,reaching maximum release within initial 2 h of simulated intestinal phase.During 4℃storage compared to storage at 25℃,it was found that the number of surviving cells is more than the recommended minimum(10^(6)CFU/g)at the end of the storage.The pH and soluble solids content of beverages containing microcapsules also signify little change.This work shows that the chitosan-coated alginate/gellan microcapsules have the potential to be used as protective microcapsules for probiotics in carbonated soft drinks.
基金financially supported by the National Natural Science Foundation of China(Grants Nos.42572064 and 42422203)the Program for Jilin University Science and Technology Innovative Research Team(Grant No.2021-TD-05)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.45124031D045)the Graduate Innovation Fund of Jilin University.
文摘Carbonated silicate melts transport oxidized carbon from the deep to shallow mantle,and thus play an important role in the deep carbon cycle.However,it is unclear how carbonated silicate melts are formed.Here,we report whole-rock major and trace element,and Mg-Zn-Fe isotope,and in situ olivine and clinopyroxene Mg isotope data for peridotites and pyroxenites in Cenozoic alkaline basalts from Shulan and Yitong,Northeast China,to reveal the formation mechanisms of carbonated silicate melts.As residues of the primitive mantle,most of the Shulan and Yitong(spinel)harzburgite and lherzolite have relatively lower δ26Mg and higher δ66Zn than the mantle values,and show LREE-enriched patterns.These features indicate that these peridotites have been modified by carbonated silicate melt,transforming them into carbonated peridotites.The Shulan websterites exhibit metasomatic textures,and most of their whole-rock and in situ δ26Mg values are lower than the mantle values,which also supports the presence of a carbonated lithospheric mantle.The Yitong cumulate orthopyroxenites,representing silica-rich melts,have lower δ26Mg and higher δ66Zn values than mantle peridotites,implying that recycled carbonate has been involved in these silica-rich melts.The Yitong cumulate wehrlites and(olivine)websterites display major element compositions similar to those of carbonated peridotite melts,coupled with low whole-rock and clinopyroxene δ26Mg values,high δ66Zn and δ57Fe values,indicating the occurrence of carbonated silicate melts.The transition from orthopyroxenites to(olivine)websterites is marked by the decreasing of their whole-rock δ26Mg,δ57Fe values and Zn/Fe ratios and increasing of their δ66Zn values,along with decreasing of their crystallization temperatures,suggesting that silica-rich melts were gradually transformed into carbonated silicate melts via continuous interaction with carbonated peridotite.Our findings demonstrate that silica-rich melts from the stagnant slab can extract carbon from pre-existing carbonated mantle within the big mantle wedge.
基金Project supported by the National Natural Science Foundation of China(52174250,92062110)the Youth Jinggang Scholars Program in Jiangxi Province(QNJG2020048)。
文摘The recovery of rare earths from industrial rare earth leaching solution is typically achieved through the ammonium carbonate precipitation method,which presents challenges in terms of prolonged production cycle and ammonia nitrogen pollution.The present study explored the synthesis of crystalline yttrium carbonate in a sodium carbonate system,employing a conventional mother liquor derived from yttrium chloride.The growth of yttrium carbonate was explored through the lens of density functional theory(DFT)calculations,unveiling a novel perspective on its formation mechanism.The synthesized yttrium carbonate demonstrates enhanced crystallinity,with a D50value of 19.75μm achieved under reaction conditions comprising a temperature of 60℃,stirring rate of 200 r/min,feeding rate of 4 mL/min,and aging time of 30 h.The molar ratio for precipitation is set at 1.6:1.The morphology of yttrium carbonate undergoes a transition from needle-like structures to sheet-like formations,ultimately culminating in the formation of spherical aggregates.The variation in surface energy among distinct crystal planes and CO_(3)^(2-)configurations within crystal cells accounts for this phenomenon.The DFT calculations unveil a progression of growth and trans formation in yttrium carbonate,commencing from a one-dimensional configuration and culminating in a multidimensional morphology.
基金Project supported by the National Natural Science Foundation of China(52274355)the National Key Research and Development Program of China(2022YFC2905305)+1 种基金the Gansu Province Science and Technology Major Special Project,China(22ZD6GD061)the Inner Mongolia Autonomous Region Science and Technology Revitalization of Inner Mongolia Cooperation Project,China(2022YFXM0001)。
文摘To solve the problem of ammonia wastewater pollution generated from preparing rare earth carbonate using the ammonium bicarbonate precipitation method,an eco-friendly precipitant,magnesium bicarbonate,was used to prepare lanthanum cerium carbonate.The lanthanum cerium sulfate solution obtained from the smelting and separation of Baotou mixed rare earth ore was used as the raw material.The influence of pH on the content of impurities,including SO^(2-)_(4)and magnesium,and the existing states of SO^(2-)_(4)n lanthanum cerium carbonate products,as well as the thermal decomposition behavior of the products,were deeply explored.SO^(2-)_(4)mainly exists in the form of rare earth sulfate complex salts in lanthanum cerium carbonate products.The fo rmation of the salts can be effectively avoided by adjusting the pH of the precipitation process.Then the content of SO^(2-)_(4)in the product is controlled.When the pH ranges from 6.00 to 7.12,the content of SO^(2-)_(4)in the product ranges from 0.42 wt%to 0.99 wt%.The content of MgO is lower than 0.04 wt%.Both contents meet the requirements of the national standard GB/T 16479-2020.In this study,lanthanum cerium carbonate products with low-content SO^(2-)_(4)were prepared.In addition,the existing states of SO^(2-)_(4)in the products are revealed.The research provides a new method for controlling the impurity content in preparing lanthanum cerium carbonate.
基金National Natural Science Foundation of China (Nos. 22371244 and 21573192)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_3463)。
文摘Transition metal-carbonate interfaces often act as active sites in heterogeneous catalytic reactions.The interface between transition metal and metal carbonate exhibits a dynamic equilibrium during the CO_(2)hydrogenation reaction,involving surface carbonate hydrogenation and CO_(2)chemisorption.Nonetheless,there have been few reports on engineering the activity of the interface between transition metal and alkaline earth metal carbonate for catalytic CO_(2)conversion.This work demonstrated that the incorporation of CaH_(2)in Ni/CaCO_(3)enhances the CO_(2)methanation activity of the catalysts.The CO_(2)conversion for Ni/CaH_(2)-CaCO_(3)reached 68.5%at 400°C,which was much higher than that of the Ni/CaCO_(3)(31.6%) and Ni/CaH_(2)-CaO (42.4%) catalysts.Furthermore,the Ni/CaH_(2)-CaCO_(3)catalysts remained stable during the stability test for 24 h at 400°C and 8 bar.Our research revealed that CaH_(2)played a crucial role in promoting the activity of the Ni-carbonate interface for CO_(2)methanation.CaH_(2)could modify the electronic structure of Ni and tune the structural properties of CaCO_(3)to generate medium basic sites (OH groups),which are favorable for the activation of H2and CO_(2).In-situ Fourier transform infrared spectroscopy (FTIR) analysis combined with density functional theory calculations demonstrated that CO_(2)activation occurs at the hydroxyl group (OH) on the CaH_(2)-modified Ni-carbonate surface,leading to the formation of CO_(3)H*species.Furthermore,our study has confirmed that CO_(2)methanation over the Ni/CaH_(2)-CaCO_(3)catalysts proceeds via the formate pathway.
基金Supported by the National Natural Science Foundation of China(U21B2062).
文摘This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistry experiment and production test data,to systematically explore the control mechanisms of structure and fluid on the scale,quality,effectiveness and connectivity of ultra-deep fault-controlled carbonate fractured-vuggy reservoirs in the Tarim Basin.The results show that reservoir scale is influenced by strike-slip fault scale,structural position,and mechanical stratigraphy.Larger faults tend to correspond to larger reservoir scales.The reservoir scale of contractional overlaps is larger than that of extensional overlaps,while pure strike-slip segments are small.The reservoir scale is enhanced at fault intersection,bend,and tip segments.Vertically,the heterogeneity of reservoir development is controlled by mechanical stratigraphy,with strata of higher brittleness indices being more conducive to the development of fractured-vuggy reservoirs.Multiple phases of strike-slip fault activity and fluid alterations contribute to fractured-vuggy reservoir effectiveness evolution and heterogeneity.Meteoric water activity during the Late Caledonian to Early Hercynian period was the primary phase of fractured-vuggy reservoir formation.Hydrothermal activity in the Late Hercynian period further intensified the heterogeneity of effective reservoir space distribution.The study also reveals that fractured-vuggy reservoir connectivity is influenced by strike-slip fault structural position and present in-situ stress field.The reservoir connectivity of extensional overlaps is larger than that of pure strike-slip segments,while contractional overlaps show worse reservoir connectivity.Additionally,fractured-vuggy reservoirs controlled by strike-slip faults that are nearly parallel to the present in-situ stress direction exhibit excellent connectivity.Overall,high-quality reservoirs are distributed at the fault intersection of extensional overlaps,the central zones of contractional overlaps,pinnate fault zones at intersection,bend,and tip segments of pure strike-slip segments.Vertically,they are concentrated in mechanical stratigraphy with high brittleness indices.
基金supported by the National Natural Science Foundation of China(No.52205310)the TUA research funding,UmeåUniversity/Region Västerbotten,Sweden(RV-937838)+1 种基金the Kempe foundation(JCSMK22-0122)the Natural Science Foundation of Shandong Province(No.ZR2021QE263).
文摘Magnesium alloy is a promising biodegradable metal material for hard tissue engineering.However,its high corrosion rate limits its application.In our previous study,we biomimetically deposited a calcium carbonate coating on the surface of magnesium alloy using siloxane induction.This calcium carbonate coating demonstrated excellent in vitro biocompatibility and provided partial protection for the magnesium alloy substrate.In this study,we further enhanced the corrosion resistance of the calcium carbonate coating by treating it with stearic acid and its derivative,sodium stearate.Electrochemical corrosion tests revealed that the sodium stearate-treated calcium carbonate coating reduced the corrosion rate by two orders of magnitude.Additionally,in vitro biocompatibility assessments showed that while the biocompatibility of the sodium stearate-treated coating was slightly reduced,it remained acceptable compared to the magnesium substrate.This study builds on our previous work and offers a promising reinforcement strategy for degradable magnesium alloys in medical applications.
基金Supported by the Joint Fund for Enterprise Innovation and Development of the National Natural Science Foundation of China(U23B20154)General Program of the National Natural Science Foundation of China(42372169)。
文摘To address the challenges in studying the pore formation and evolution processes,and unclear preservation mechanisms of deep to ultra-deep carbonate rocks,a high-temperature and high-pressure visualization simulation experimental device was developed for ultra-deep carbonate reservoirs.Carbonate rock samples from the Sichuan Basin and Tarim Basin were used to simulate the dissolution-precipitation process of deep to ultra-deep carbonate reservoirs in an analogous geological setting.This unit comprises four core modules:an ultra-high temperature,high pressure triaxial stress core holder module(temperature higher than 300°C,pressure higher than 150 MPa),a multi-stage continuous flow module with temperature-pressure regulation,an ultra-high temperature-pressure sapphire window cell and an in-situ high-temperature-pressure fluid property measurement module and real-time ultra-high temperature-pressure permeability detection module.The new experimental device was used for simulation experiment,the geological insights were obtained in three aspects.First,the pore-throat structure of carbonate is controlled by lithology and initial pore-throat structure,and fluid type,concentration and dissolution duration determine the degree of dissolution.The dissolution process exhibits two evolution patterns.The dissolution scale is positively correlated to the temperature and pressure,and the pore-forming peak period aligns well with the hydrocarbon generation peak period.Second,the dissolution potential of dolomite in an open flow system is greater than that of limestone,and secondary dissolved pores formed continuously are controlled by the type and concentration of acidic fluids and the initial physical properties.These pores predominantly distribute along pre-existing pore/fracture zones.Third,in a nearly closed diagenetic system,after the chemical reaction between acidic fluids and carbonate rock reaches saturation and dynamic equilibrium,the pore structure no longer changes,keeping pre-existing pores well-preserved.These findings have important guiding significance for the evaluation of pore-throat structure and development potential of deep to ultra-deep carbonate reservoirs,and the prediction of main controlling factors and distribution of high-quality carbonate reservoirs.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2062)supported by the Key Laboratory for Carbonate Reservoirs of China National Petroleum Corporation。
文摘Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.
基金Project(2021YJ059)supported by the Research Project of China Academy of Railway Sciences。
文摘The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated to assess erosion depth,microstructure,phase migrations,and pore structure in various tunnel lining cement-based materials.Additionally,Ca^(2+)leaching was analyzed,and impact of Ca/Si molar ratio in hydration products on erosion resistance was discussed by thermodynamic calculations.The results indicate that carbonated water erosion caused rough and porous surface on specimens,with reduced portlandite and CaCO_(3) content,increased porosity,and an enlargement of pore size.The thermodynamic calculations indicate that the erosion is spontaneous,driven by physical dissolution and chemical reactions dominated by Gibbs free energy.And the erosion reactions proceed more spontaneously and extensively when Ca/Si molar ratio in hydration products was higher.Therefore,cement-based materials with higher portlandite content exhibit weaker erosion resistance.Model-building concrete,with C-S-H gel and portlandite as primary hydration products,has greater erosion susceptibility than shotcrete with ettringite as main hydration product.Moreover,adding silicon-rich mineral admixtures can enhance the erosion resistance.This research offers theory and tech insights to boost cement-based material resistance against carbonated water erosion in karst tunnel engineering.
文摘Indoles and their derivatives are an important class of N-heterocycles.In this article,iridium-catalyzed annulation reactions of N-aryl-2-aminopyridines to synthesize indole derivatives are designed and developed,which utilize vinylene carbonate as a new C2 synthon.This protocol is expected to provide a facile and useful access to various indole derivatives.
文摘A single component molybdenum catalyst was synthesized and its activity in the cycloaddition reaction of CO_(2)and epoxide was tested.The results show that the molybdenum catalysts exhibit high activity and a broad substrate scope under the reaction conditions of 80℃and 0.5 MPa of CO_(2),solvent-free,and and no nucleophilic cocatalysts,affording a wide range of cyclic carbonates in yields of 42%~94%.The reaction mechanism was investigated using in situ infrared(in situ IR),high-resolution mass spectrometry(HRMS)and Fourier transform infrared spectroscopy(FT-IR).
基金supported by Fundamental Research Program of Shanxi Province(202203021221303)。
文摘Transformation of urea and glycerol to glycerol carbonate is an environmental friendly and economical process.Catalysts play an indispensable role in the process.Although many catalysts have been developed,the performance of the catalysts still cannot meet the needs of industrialization.In this paper,research progress of the homogeneous and heterogeneous catalysts of the reaction over the past 20 years were reviewed systematically.According to the types and active centers of catalysts,the catalysts were classified systematically and analyzed in detail.The typical reaction mechanisms were also summarized.The research and development direction of catalysts is made more explicit through systematic classification and mechanism analysis.The article reveals more novel catalysts have been designed and used for the reaction,such as mixed metal oxides with special structures,solid wastes and non-metallic materials.This work summarized the current state of research and prospected possible routes for design of novel catalysts.It is hoped that this review can provide some references for developing efficient catalysts.
基金Jiangsu Province Key Project of Research and Development Plan(No.BE2020676)Nantong Science and Technology Project(No.MS22021006)。
文摘Filtration is a prevalent treatment modality in the domain of wastewater management.Depending on the materials and properties of the filtration media,filtration can be classified into four main categories:microfiltration,ultrafiltration,nanofiltration,and reverse osmosis.The present study focuses on the preparation of a novel porous CaCO_(3)microfiltration membrane,which is based on the microbial-induced calcium carbonate precipitation(MICP)biomineralization process.Initially,CaCO_(3) crystal particles with urease activity are prepared by controlling the MICP mineralization process.Secondary microbial mineralization is used to cement the loose calcium carbonate particles,forming a continuous porous solid CaCO_(3)membrane with certain mechanical strength.Filtration tests on bacterial cells,extracellular proteins,and polysaccharides show that the MICP-driven porous CaCO_(3) membrane effectively removes Escherichia coli,Brachybacterium sp.,and activated sludge,with removal rates of 99.998%,99.983%,and 99.996%,respectively.Compared to conventional filter paper,this porous CaCO_(3) membrane demonstrates superior capability in removing extracellular polymers(EPS).Furthermore,the CaCO_(3) microfiltration membrane prepared using the MICP process also exhibits ideal pore space,non-blocking characteristics,and high permeability.
基金C.Lana and F.F.Alkmim benefit from the Brazilian National Research Council(CNPq)research grants 3073353/2019-2 and 311543/2020-0.C.Lana,F.F.Alkmim,and Maria Eugênia Souza are part of the Instituto GeoAtlântico,a National Institute of Science and Technology,CNPq-Brazil process 405653/2022-0We acknowledge Petrobras’s support during the investigation and permission to publish this study.I.Figueiredo acknowledged the Brazilian Federal Agency for Support and Evaluation of Graduate Education(CAPES)for Master's scholarship 88887.816343/2023-00.
文摘The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma.
基金supported by Science,Technology&Innovation Funding Authority(STDF)under grant(No.47062).
文摘Conversion and capture of carbon pollutants based on carbon dioxide to valuable green oil-field chemicals are target all over the world for controlling the global warming.The present article used new room temperature amphiphilic imidazolium ionic liquids with superior surface activity in the aqueous solutions to convert carbon dioxide gas to superior amphiphilic calcium carbonate nanoparticles.In this respect,tetra-cationic ionic liquids 2-(4-dodecyldimethylamino)phenyl)-1,3-bis(3-dodecyldimethylammnonio)propyl)bromide-1-H-imidazol-3-ium acetate and 2-(4-hexyldimethylamino)phenyl)-1,3-bis(3-hexcyldimethylammnonio)propyl)bromide-1 H-imidazol-3-ium acetate were prepared.Their chemical structures,thermal as well as their carbon dioxide absorption/desorption characteristicswere evaluated.Theywere used as solvent and capping agent to synthesize calcium carbonate nanoparticles with controlled crystalline lattice,sizes,thermal properties and spherical surface morphologies.The prepared calcium carbonate nanoparticles were used as additives for the commercial water based drilling mud to improve their filter lose and rheology.The data confirm that the lower concentrations of 2-(4-dodecyldimethylamino)phenyl)-1,3-bis(3-dodecyldimethylammnonio)propyl)bromide-1-H-imidazol-3-ium acetate achieved lower seawater filter lose and improved viscosities.
基金financially supported by the Maoming Science and Technology Bureau(No.2022DZXHT007)。
文摘The synthesis of polyurethanes(PUs)from the reaction of low molecular weight poly(ethylene carbonate)diol(PECD)is rarely investigated.This work reports a novel PU with excellent mechanical properties from the solution polymerization of 4,4-diphenylmethane diisocyanate(MDI)with PECD that was derived from the copolymerization of carbon dioxide(CO_(2))and ethylene oxide(EO).The tensile strength,the elongation at break and 300%constant tensile strength of the PECD-PU were up to 66±2 MPa,880%±50%and 13 MPa,respectively,higher than the control PUs from the reaction of MDI with commercial polyethers or polyesters.The PECD-PU with high CO_(2) carbonate content exhibited good solvent resistance and chemical stability.Of importance,the mechanical properties and chemical resistance of PECD-PU were significantly enhanced with the increasing content of CO_(2),i.e.,the carbonate unit in PECD.This work provides comprehensive properties of PECD-derived PUs,indicating that PECD is a competitive precursor for the preparation of PU and has broad application prospects.
