Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,envir...Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,environmental engineering,and biomedicine.There-fore,the obtained research results need to be systematically summarized,and new perspectives on CF and its composite materials need to be analyzed.Based on the presented studies of CF and its composite materials,the types and structures of the crystal are summarized.In addition,the current application technologies and theoretical mechanisms with various properties in different fields are elucidated.Moreover,the various preparation methods of CF and its composite materials are elaborated in detail.Most importantly,the advantages and disadvantages of the synthesis methods of CF and its composite materials are discussed,and the existing problems and emerging challenges in practical production are identified.Furthermore,the key future research directions of CF and its composite materials have been prospected from the potential application technologies to provide references for its synthesis and efficient utilization.展开更多
The reaction characteristics of calcium-based materials during calcium looping(CaL)process are pivotal in the efficiency of CaL thermochemical energy storage(TCES)and CO_(2)capture systems.Currently,metal oxide doping...The reaction characteristics of calcium-based materials during calcium looping(CaL)process are pivotal in the efficiency of CaL thermochemical energy storage(TCES)and CO_(2)capture systems.Currently,metal oxide doping is the primary method to enhance the reaction characteristics of calcium-based materials over multiple cycles.In particular,co-doping with variable-valence metal oxides(VVMOs)can effectively increase the oxygen vacancy content in calcium-based materials,significantly improving their cyclic reaction characteristics.However,there are so numerous VVMOs co-doping schemes that the experimental screening process is complex,consuming considerable time and economic costs.Density functional theory(DFT)calculations have been widely used to reveal the impact of metal oxide doping on the cyclic reaction characteristics of calcium-based materials,with calculation results showing good agreement with experimental conclusions.Nevertheless,there is still a lack of research on utilizing DFT to screen calcium-based materials,and a systematic research methodology has not yet been established.In this study,a systematic DFT-based screening methodology for calcium-based materials was proposed.A series of key parameters for DFT calculations including CO_(2)adsorption energy,oxygen vacancy formation energy,and sintering resistance were proposed.Furthermore,a preliminary mathematical model to predict the CaL TCES and CO_(2)capture performance of calcium-based materials was introduced.The aforementioned DFT method was employed to screen for VVMOs co-doped calcium-based materials.The results revealed that Mn and Ce co-doped calcium-based materials exhibited superior DFT-predicted reaction characteristics.These DFT predictions were validated through experimental assessments of cyclic thermochemical energy storage,CO_(2)capture,and relevant characterization.The outcomes demonstrate a high degree of consistency among DFT-based predictions,experimental results,and characterization.Hence,the DFT-based screening methodology for calcium-based materials proposed herein is a viable solution,poised to offer theoretical insights for the efficient design of calcium-based materials.展开更多
The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self...The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.展开更多
Doped calcium carbonate-phosphate is a biocompatible material that influence actively on the osteogenesis, bone regenerate, strengthening of bone and dental tissues including through the skin. A mechanism of the synth...Doped calcium carbonate-phosphate is a biocompatible material that influence actively on the osteogenesis, bone regenerate, strengthening of bone and dental tissues including through the skin. A mechanism of the synthesis reactions of doped nanocrystalline calcium carbonate-phosphate an oscillating type of model for these reactions is proposed. The results indicate that the synthesis involves the formation of hydroxy carbonate complexes from the three calcium carbonate polymorphs (calcite, vaterite, and aragonite) in a solution of ammonium chloride and ammonium carbonate, followed by reaction with orthophosphoric acid. The formation of nanocrystalline calcium carbonate-phosphate doped with Fe2+, Mg2+, Zn2+, K+, Si4+, and Mn2+, has been studied by X-ray diffraction, IR spectroscopy, differential thermal analysis, and energy dispersive X-ray fluorescence analysis. This ensures the preparation of a bioactive material based on octacalcium hydrogen phosphate, and calcium chloride hydroxide phosphates containing cation vacancies. Particle-size analysis data show that the materials contain nanoparticles down to 10 nm in size. Heat treatment of the doped calcium carbonate phosphates produces calcium hydroxyapatite containing cation vacancies, which can be used as a bioactive ceramic.展开更多
Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a...Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a bone repair scaffold material for physicochemical property characterization and testing.Methods:The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and scanning electron microscopy;Universal material testing machine to determine the mechanical and mechanical strength of composite materials.Results:XRD showed that the structure of the composite material phase at 5%concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration.The FT-IR and XRD analyses were consistent.Scanning electron microscopy(SEM)results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material.0%,1%,5%,and 10%specimen groups had compressive strengths of 3.86±3.1,5.27±1.28,8.22±0.96,and 14.4±3.28 MPa.10%addition of calcium hydroxide significantly improved the mechanical strength of the composites,but also reduced the the porosity of the material.Conclusion:With the addition of calcium hydroxide,the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material.展开更多
Design and preparation of novel advanced carbon materials with unique architecture and functional groups is of great significance.Herein,a spongy acetylenic carbon material(SACM) was prepared through mechanochemical r...Design and preparation of novel advanced carbon materials with unique architecture and functional groups is of great significance.Herein,a spongy acetylenic carbon material(SACM) was prepared through mechanochemical reaction of CaC2 and chlorinated rubber in a planetary ball mill at ambient temperature.Its composition and structure were characterized,and its electrochemical properties and adsorption performance for Hg^2+ were studied.The SACM is composed of submicron spongy aggregates with high carbon content(81.8%) and specific area(503.9 m^2·g^-1),rich porosity and acetylenic groups.The SACM exhibits excellent adsorption for Hg2+with saturated adsorption amount being 157.1 mg·g^-1,which is superior to conventional carbon materials.Further,it exhibits good electrochemical performance with low equivalent series resistance(0.50 Ω),excellent cycling stability and ideal double layer capacitive behavior.This paper provides a novel and universal synthesis method of spongy carbon materials,and better results can be expected through tuning the pore structure,graphitization degree,and heteroatoms of the target carbon materials.展开更多
The duck eggshell waste was developed to the novel desiccant that is friendly to human and environment.The calcium oxide(Ca O)and calcium chloride(CaCl_(2))as the calcium-based desiccants were prepared from eggshell w...The duck eggshell waste was developed to the novel desiccant that is friendly to human and environment.The calcium oxide(Ca O)and calcium chloride(CaCl_(2))as the calcium-based desiccants were prepared from eggshell waste.The Ca O desiccant derived from the eggshell waste sintering at 1300℃,while the CaCl_(2)desiccant was extracted from eggshell waste with the hydrochloric(HCl)solution at difierent concentrations from 5 to 30 wt%.The yield percentage of CaCl_(2)desiccant increased with increasing the HCl concentration to 25 wt%.The humidity adsorption behavior were investigated in the range of 75%-5%relative humidity.The results show the CaCl_(2)desiccant has the highest hydration rate.The porous host from the kaolin was sintered at different temperatures from 200 to 1000℃and incorporated with 30%w/v concentrations of CaCl_(2).The physical properties and the humid-adsorption capacity of all porous host conditions were investigated.The porous host at sintering temperature 800℃has the highest specific surface area.Moreover,the porous host at sintering temperature 800℃with the 30%w/v concentration of CaCl_(2)desiccant has the highest humid-adsorption capacity.展开更多
Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA ex...Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA extraction is an essential step in gene expression study using RT-qPCR. In this study, we describe simple modifications to the TRIzol? RNA extraction protocol widely used in biology and these allow high-yield extraction of RNA from cells on resorbable calcium phosphates. Without the modifications, RNA is trapped in the co-precipitated calcium compounds, rendering TRIzol? extraction method infeasible. Among the modifications, the use of extra TRIzol? to dilute the lysate before the RNA precipitation step is critical for extraction of RNA from porous ?-tricalcium phosphate (?-TCP) discs. We also investigate the rationale behind the undesirable precipitation so as to provide clues about the modifications required for other resorbable materials with high application potential in bone tissue engineering.展开更多
This paper investigates the stabilization effect on compressed earth blocks (CEB) produced from quartz-kaolinite rich earthen material stabilized with 0% - 25% calcium carbide residue (CCR). The paper evaluated variou...This paper investigates the stabilization effect on compressed earth blocks (CEB) produced from quartz-kaolinite rich earthen material stabilized with 0% - 25% calcium carbide residue (CCR). The paper evaluated various physico-thermal properties of the stabilized CEB and thermal comfort in the model building made of CEB masonry. The optical properties of CEB were evaluated from the mineral composition of the earthen material and CCR and apparent density of the CEB. A simulation was carried out on naturally ventilated model building whose masonry is made of CCR stabilized CEB comparing to the so-called conventional cementitious materials such as cement blocks and concrete. The results showed a decrease of the apparent density of the CEB from 2100 kg·m–3 for unstabilized CEB (0% CCR) to 1600 kg·m–3 for 25% CCR stabilized CEB. The thermal conductivity and depth of penetration of the heat flux on a 24 hours period of CEB respectively decreased from 1 W·m–1·K–1 and 12.7 cm for 0% CCR-CEB to 0.5 W·m–1·K–1 and 10.2 cm for 25% CCR-CEB. The emissivity, solar absorptivity and visible absorptivity of the CEB respectively decreased from 0.82, 0.82 and 0.82 for 0% CCR-CEB to 0.80, 0.64 and 0.64 for 25% CCR-CEB. The number of hours of warm and humid thermal discomfort was impacted for stabilized CEB based masonry in comparison with cement based masonry. The warm discomfort in building made of 20% CCR-CEB masonry was 400 hours lesser than that in building made of hollow cement blocks masonry. If air conditioning system is used to keep the indoor temperature below 28°C, the economy of 310,000 CFA francs (535 USD) is made every year on energy consumption for cooling in the model building made of 20% CCR-CEB masonry, corresponding to 9.6% less, with respect to that made of hollow cement blocks masonry.展开更多
We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, unifor...We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of Ca Cl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power（SCP） at 5 min adsorption time can reach as high as 0.19 g·g^-1 and 793.9 W·kg^-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.Key words： biomass material; adsorption system; ammonia; calcium chloride; activated carbon展开更多
Micro-pored CA6 -MA lightweight material with CAM： MA mass ratio of 7：3 was prepared using Al（OH） 3, MgCO3 and CaCO3 as starting materials, and anthracite. sweet potato starch and anthracite ＋ sweet potato starch...Micro-pored CA6 -MA lightweight material with CAM： MA mass ratio of 7：3 was prepared using Al（OH） 3, MgCO3 and CaCO3 as starting materials, and anthracite. sweet potato starch and anthracite ＋ sweet potato starch as pore forming agent （PFA） with an addition of 10 mass%, 20 mass% and 30 mass%, respectively. The starting materials were dry mixed, wet co-milled in a ball mill for 1 h. slip cast into cylindrical specimens with a diameter of 60 ram. and then calcined at 1 450 ℃ for 3 h. With the increase of PFA addition,, apparent porosity increases, and bulk density decreases. The influence of different PFAs on properties of the micro-pored LW CAM -MA aggregate was investigated. The achieved CAM - MA, by adding 30% sweet potato starch, has a porosity of 76. 8%, bulk density of 0. 78 g · cm^ - 3 and median pore size of 1.90 μm.展开更多
Mineral trioxide aggregate (MTA) cement is an attractive material in endodontic dentistry. The purpose of this study was to produce calcium silicate, which is a major component of MTA, from waste materials. A dental a...Mineral trioxide aggregate (MTA) cement is an attractive material in endodontic dentistry. The purpose of this study was to produce calcium silicate, which is a major component of MTA, from waste materials. A dental alginate impression gel and used chalks were selected and mixed in a suitable ratio (Code: EXP). As a control, CaCO3 and a commercial diatomite were used (Code: CON). Each powder was heated to 850。C and 1000。C, and then kneaded with water. TG-DTA, compressive tests, SEM observations, elemental mapping analyses, and XRD analyses were performed. TG-DTA indicated that weight reduction of CaCO3 started at 600。C, and it completely decomposed on heating at 850。C. The strength was affected by the temperature. After heating, CaCO3 was transformed into CaO and/or Ca2SiO4, and Ca(OH)2 was formed by mixing with water. There were no differences between EXP and CON. These data suggested that recycled wastes might be promising MTA sources.展开更多
Eggshell powder is a powdered product that is made from discarded eggshells. It is rich in inorganic salts and a small number of organic substances. Aliphatic polyester is one of the most promising polymer materials a...Eggshell powder is a powdered product that is made from discarded eggshells. It is rich in inorganic salts and a small number of organic substances. Aliphatic polyester is one of the most promising polymer materials at present. Aliphatic polyester has not only a wide range of sources, but also excellent biodegradability and biocompatibility. Three kinds of aliphatic polyester composites were mixed with PCL, PBS, PHA, PLA and Ag powder as raw materials through solution reinforcement by eggshell powder. The thermal properties and structures of the three materials were analyzed and characterized by differential scanning calorimetry and scanning electron microscopy. DSC and SEM were used to analyze and characterize the thermal properties and structures of the three composites. The experimental results show that the GTT(glass-transition temperature) are 91.9°C, 89.3°C, and 87.2°C, the melting points are all greater than 92°C, and the enthalpy changes are respectively -37.8J/g, -23.9J/g, -22.2 J/g,. Among them, the composite material of PCL, PBS and eggshell powder, and Ag powder has excellent performance, showing good thermal performance and thermal stability. Moreover, the production and utilization of eggshell powder, turning waste into wealth, has important economic value for the sustainable development of circular ecology.展开更多
In this manuscript, we describe the novel method for preparing the microcapsules containing α-tocopherol oil droplets as the first core material, calcium chloride powder as the second core material and the fine water...In this manuscript, we describe the novel method for preparing the microcapsules containing α-tocopherol oil droplets as the first core material, calcium chloride powder as the second core material and the fine water droplets as the third core material by the interfacial condensation reaction between hydroxyl propyl methyl cellulose and tannic acid. The interfacial condensation reaction was performed between hydroxyl propyl methyl cellulose dissolved in the continuous water phase and tannic acid dissolved in the inner fine water droplets as the third core material. The calcium chloride powder as the second core material was dispersed in the α-tocopherol oil droplet as the first core material beforehand. The α-tocopherol oil containing the second and the third core materials was dispersed in the continuous water phase to form the [(S + W)/O/W] emulsion. The α-tocopherol oil as the first core material was microencapsulated satisfactorily and the contents of the second core material were increased with the concentration of stearic acid as the oil soluble stabilizer. The mechanical strength of microcapsules increased with the concentration of hydroxyl propyl methyl cellulose. Thermal energy could be released by breaking the microcapsules in water and by dissolving calcium chloride in the continuous water phase.展开更多
Degradation of nitrobenzene(NB)via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation.However,the poor stability of H2O2limits the application of traditional Fenton re...Degradation of nitrobenzene(NB)via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation.However,the poor stability of H2O2limits the application of traditional Fenton reactions in soil and groundwater due to the transportation risks of H_(2)O_(2).In this study,we synthesized a controlled release nano calcium peroxide(n CP)by coating it with polydopamine(PDA)as a solid H2O2to construct a Fe(Ⅱ)/PDA@n CP Fenton-like system for contaminants degradation.The phenolquinone transformations of catechol groups on the PDA surface facilitated the Fe(Ⅱ)/Fe(Ⅲ)cycle,resulting in enhanced generation of hydroxyl radicals(HO·)and effective long-term degradation of NB.Moreover,the PDA shell modulated the n CP decomposition rate and inhibited sharp p H fluctuations,and the NB removal efficiency was achieved up to 96.8%at p H ranging from 3.0 to 9.0.This study demonstrated the promising application potential of PDA@n CP as a solid-controlled release H2O2source in Fenton-like system for groundwater contamination remediation.展开更多
Coal fly ash is a typical secondary aluminum/silicon resource.The preparation of zeolite-type absorbent is a potential way for its value-added utilization,while the purity and adsorption property of zeolite are limite...Coal fly ash is a typical secondary aluminum/silicon resource.The preparation of zeolite-type absorbent is a potential way for its value-added utilization,while the purity and adsorption property of zeolite are limited due to the occurrence of side reactions in the synthesis process.In this study,a designated composite consisted of crystalline zeolites and amorphous calcium silicate hydrate was selected,which was direct synthesized from fly ash under conditions of a Ca/Si molar ratio of 0.8,an initial NaOH concentration of 0.5 mol/L,a hydrothermal temperature of 170℃and a liquid–solid ratio of 15 mL/g.The results indicated that this composite had superior adsorption property for a variety of heavy metals,which was based on the exchange of calcium and sodium ions in zeolites and calcium silicate hydrate.Its adsorption capacities for Pb^(2+),Ni^(2+),Cd^(2+),Zn^(2+),Cu^(2+)and Cr^(3+)attained 409.4,222.4,147.5,93.2,101.1 and 157.0 mg/g,respectively,in single solution with a pH of 4.5.After regulating the synthesis conditions,the transformation of amorphous calcium silicate hydrate into crystallized tobermorite weakened the adsorption capacity of the composite.Besides,due to the competitive adsorption in a multiple ions solution,the adsorption capacities for these heavy metals had a reduction.展开更多
Magnesium(Mg^2+))ion plays important roles in biomineralization of bone,teeth and calcium carbonate skeletons.Herein,chicken eggshells mainly comprising of Mg-calcite nanocrystals(Mg/(Mg+Ca)2.0 mol.%)were used to fabr...Magnesium(Mg^2+))ion plays important roles in biomineralization of bone,teeth and calcium carbonate skeletons.Herein,chicken eggshells mainly comprising of Mg-calcite nanocrystals(Mg/(Mg+Ca)2.0 mol.%)were used to fabricate biphasic calcium phosphate(BCP),a mixture of hydroxyapatite(HA)and p-tricalcium phosphate(p-TCP)nanocrystals,through hydrothermal reactions at 200℃for 24 h.Our results indicated thatβ-TCP nanocrystals formed through the ion-exchange reactions of Mg-calcite,while HA nanocrystals were mainly produced by dissolution-reprecipitation reactions on the surfaces of eggshell samples in the hydrothermal system.Mg substitution in calcite resulted in formation ofβ-TCP nanocrystals instead of HA crystals through ion-exchange reactions.BCP samples with different compositions(28.6-77.8 wt.%β-TCP)were produced by controlling particle sizes of eggshells for hydrothermal reactions.The larger particles lead to the larger proportion ofβ-TCP in the BCP composition.Therefore,Mg substitution and particle size had synergetic effects on the hydrothermal synthesis of BCP using chicken eggshells through balance of ion-exchange and dissolution-reprecipitation reactions.Cell culture results showed that the BCP products were non-cytotoxic to MC3 T3-E1 cells,which may be used for bone substitute materials in future.展开更多
BACKGROUND The success rate of conservative endodontic management for root fracture varies greatly based on different methods used.It has been rarely reported that calcium silicate-based materials are applied in root ...BACKGROUND The success rate of conservative endodontic management for root fracture varies greatly based on different methods used.It has been rarely reported that calcium silicate-based materials are applied in root fracture treatment.CASE SUMMARY A 38-year-old male patient presented with spontaneous pain from the upper left anterior teeth for 1 wk.The spontaneous pain was subsequently relieved,but pain on mastication persisted for 3 d.The patient had a dental trauma from a boxing match 15 years ago.Cone beam computed tomography showed that the maxillary left central incisor had oblique fracture lines and a radiolucent lesion around the fracture line.The tooth was diagnosed with an oblique root fracture with no healing and symptomatic apical periodontitis.In the following conservative endodontic management,the coronal and apical fragments of the canal both were chemo-mechanically prepared and obturated using a single cone gutta-percha with iRoot SP(Innovative BioCreamix Inc,Vancouver,Canada),a new calcium silicate-based bioceramic root canal sealer.At follow-ups at 1,6,12,and 24 mo,the patient was asymptomatic and the radiolucency around the fracture line was healing radiographically.CONCLUSION Conservative root canal treatment is an alternative treatment in some cases of oblique root fracture with no healing.The application of bioceramic sealers and single core obturation techniques may also be essential to obtain an excellent outcome.展开更多
基金supported by the National Natural Science Foundation of China(No.51574105)the Science and Technology Program of Hebei Province,China(No.23564101D)+2 种基金the Natural Science Foundation of Hebei Province,China(No.E2021209147)the Key Research Project of North China University of Science and Technology(No.ZD-ST-202308)the Postgraduate Innovation Funding Project of Hebei Province,China(No.CXZZBS2024135).
文摘Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,environmental engineering,and biomedicine.There-fore,the obtained research results need to be systematically summarized,and new perspectives on CF and its composite materials need to be analyzed.Based on the presented studies of CF and its composite materials,the types and structures of the crystal are summarized.In addition,the current application technologies and theoretical mechanisms with various properties in different fields are elucidated.Moreover,the various preparation methods of CF and its composite materials are elaborated in detail.Most importantly,the advantages and disadvantages of the synthesis methods of CF and its composite materials are discussed,and the existing problems and emerging challenges in practical production are identified.Furthermore,the key future research directions of CF and its composite materials have been prospected from the potential application technologies to provide references for its synthesis and efficient utilization.
基金supported by the National Natural Science Foundation of China(52276204 and U22A20435)。
文摘The reaction characteristics of calcium-based materials during calcium looping(CaL)process are pivotal in the efficiency of CaL thermochemical energy storage(TCES)and CO_(2)capture systems.Currently,metal oxide doping is the primary method to enhance the reaction characteristics of calcium-based materials over multiple cycles.In particular,co-doping with variable-valence metal oxides(VVMOs)can effectively increase the oxygen vacancy content in calcium-based materials,significantly improving their cyclic reaction characteristics.However,there are so numerous VVMOs co-doping schemes that the experimental screening process is complex,consuming considerable time and economic costs.Density functional theory(DFT)calculations have been widely used to reveal the impact of metal oxide doping on the cyclic reaction characteristics of calcium-based materials,with calculation results showing good agreement with experimental conclusions.Nevertheless,there is still a lack of research on utilizing DFT to screen calcium-based materials,and a systematic research methodology has not yet been established.In this study,a systematic DFT-based screening methodology for calcium-based materials was proposed.A series of key parameters for DFT calculations including CO_(2)adsorption energy,oxygen vacancy formation energy,and sintering resistance were proposed.Furthermore,a preliminary mathematical model to predict the CaL TCES and CO_(2)capture performance of calcium-based materials was introduced.The aforementioned DFT method was employed to screen for VVMOs co-doped calcium-based materials.The results revealed that Mn and Ce co-doped calcium-based materials exhibited superior DFT-predicted reaction characteristics.These DFT predictions were validated through experimental assessments of cyclic thermochemical energy storage,CO_(2)capture,and relevant characterization.The outcomes demonstrate a high degree of consistency among DFT-based predictions,experimental results,and characterization.Hence,the DFT-based screening methodology for calcium-based materials proposed herein is a viable solution,poised to offer theoretical insights for the efficient design of calcium-based materials.
基金Project(2018YFC0705404)supported by the National Key Technology Research and Development of ChinaProjects(51878480,51678442,51878481,51878496)supported by the National Natural Science Foundation of China+1 种基金Project(U1534207)supported by the National High-speed Train Union Fund,ChinaProject supported by the Fundamental Research Funds for the Central Universities,China
文摘The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.
文摘Doped calcium carbonate-phosphate is a biocompatible material that influence actively on the osteogenesis, bone regenerate, strengthening of bone and dental tissues including through the skin. A mechanism of the synthesis reactions of doped nanocrystalline calcium carbonate-phosphate an oscillating type of model for these reactions is proposed. The results indicate that the synthesis involves the formation of hydroxy carbonate complexes from the three calcium carbonate polymorphs (calcite, vaterite, and aragonite) in a solution of ammonium chloride and ammonium carbonate, followed by reaction with orthophosphoric acid. The formation of nanocrystalline calcium carbonate-phosphate doped with Fe2+, Mg2+, Zn2+, K+, Si4+, and Mn2+, has been studied by X-ray diffraction, IR spectroscopy, differential thermal analysis, and energy dispersive X-ray fluorescence analysis. This ensures the preparation of a bioactive material based on octacalcium hydrogen phosphate, and calcium chloride hydroxide phosphates containing cation vacancies. Particle-size analysis data show that the materials contain nanoparticles down to 10 nm in size. Heat treatment of the doped calcium carbonate phosphates produces calcium hydroxyapatite containing cation vacancies, which can be used as a bioactive ceramic.
基金National Natural Science Foundation of China(No.82060347)Postgraduate innovation research project of Hainan Medical College(No.HYYS2020-38)。
文摘Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a bone repair scaffold material for physicochemical property characterization and testing.Methods:The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and scanning electron microscopy;Universal material testing machine to determine the mechanical and mechanical strength of composite materials.Results:XRD showed that the structure of the composite material phase at 5%concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration.The FT-IR and XRD analyses were consistent.Scanning electron microscopy(SEM)results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material.0%,1%,5%,and 10%specimen groups had compressive strengths of 3.86±3.1,5.27±1.28,8.22±0.96,and 14.4±3.28 MPa.10%addition of calcium hydroxide significantly improved the mechanical strength of the composites,but also reduced the the porosity of the material.Conclusion:With the addition of calcium hydroxide,the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material.
基金Supported by National Natural Science Foundation of China(21776015)
文摘Design and preparation of novel advanced carbon materials with unique architecture and functional groups is of great significance.Herein,a spongy acetylenic carbon material(SACM) was prepared through mechanochemical reaction of CaC2 and chlorinated rubber in a planetary ball mill at ambient temperature.Its composition and structure were characterized,and its electrochemical properties and adsorption performance for Hg^2+ were studied.The SACM is composed of submicron spongy aggregates with high carbon content(81.8%) and specific area(503.9 m^2·g^-1),rich porosity and acetylenic groups.The SACM exhibits excellent adsorption for Hg2+with saturated adsorption amount being 157.1 mg·g^-1,which is superior to conventional carbon materials.Further,it exhibits good electrochemical performance with low equivalent series resistance(0.50 Ω),excellent cycling stability and ideal double layer capacitive behavior.This paper provides a novel and universal synthesis method of spongy carbon materials,and better results can be expected through tuning the pore structure,graphitization degree,and heteroatoms of the target carbon materials.
基金the research professional development project under the Science Achievement Scholarship of Thailand(SAST)for education financial support。
文摘The duck eggshell waste was developed to the novel desiccant that is friendly to human and environment.The calcium oxide(Ca O)and calcium chloride(CaCl_(2))as the calcium-based desiccants were prepared from eggshell waste.The Ca O desiccant derived from the eggshell waste sintering at 1300℃,while the CaCl_(2)desiccant was extracted from eggshell waste with the hydrochloric(HCl)solution at difierent concentrations from 5 to 30 wt%.The yield percentage of CaCl_(2)desiccant increased with increasing the HCl concentration to 25 wt%.The humidity adsorption behavior were investigated in the range of 75%-5%relative humidity.The results show the CaCl_(2)desiccant has the highest hydration rate.The porous host from the kaolin was sintered at different temperatures from 200 to 1000℃and incorporated with 30%w/v concentrations of CaCl_(2).The physical properties and the humid-adsorption capacity of all porous host conditions were investigated.The porous host at sintering temperature 800℃has the highest specific surface area.Moreover,the porous host at sintering temperature 800℃with the 30%w/v concentration of CaCl_(2)desiccant has the highest humid-adsorption capacity.
文摘Resorbable bioceramics are attractive for medical applications such as bone substitution. Biochemical analysis on cells cultured on these biomaterials is vital to predict the impact of the materials in vivo and RNA extraction is an essential step in gene expression study using RT-qPCR. In this study, we describe simple modifications to the TRIzol? RNA extraction protocol widely used in biology and these allow high-yield extraction of RNA from cells on resorbable calcium phosphates. Without the modifications, RNA is trapped in the co-precipitated calcium compounds, rendering TRIzol? extraction method infeasible. Among the modifications, the use of extra TRIzol? to dilute the lysate before the RNA precipitation step is critical for extraction of RNA from porous ?-tricalcium phosphate (?-TCP) discs. We also investigate the rationale behind the undesirable precipitation so as to provide clues about the modifications required for other resorbable materials with high application potential in bone tissue engineering.
文摘This paper investigates the stabilization effect on compressed earth blocks (CEB) produced from quartz-kaolinite rich earthen material stabilized with 0% - 25% calcium carbide residue (CCR). The paper evaluated various physico-thermal properties of the stabilized CEB and thermal comfort in the model building made of CEB masonry. The optical properties of CEB were evaluated from the mineral composition of the earthen material and CCR and apparent density of the CEB. A simulation was carried out on naturally ventilated model building whose masonry is made of CCR stabilized CEB comparing to the so-called conventional cementitious materials such as cement blocks and concrete. The results showed a decrease of the apparent density of the CEB from 2100 kg·m–3 for unstabilized CEB (0% CCR) to 1600 kg·m–3 for 25% CCR stabilized CEB. The thermal conductivity and depth of penetration of the heat flux on a 24 hours period of CEB respectively decreased from 1 W·m–1·K–1 and 12.7 cm for 0% CCR-CEB to 0.5 W·m–1·K–1 and 10.2 cm for 25% CCR-CEB. The emissivity, solar absorptivity and visible absorptivity of the CEB respectively decreased from 0.82, 0.82 and 0.82 for 0% CCR-CEB to 0.80, 0.64 and 0.64 for 25% CCR-CEB. The number of hours of warm and humid thermal discomfort was impacted for stabilized CEB based masonry in comparison with cement based masonry. The warm discomfort in building made of 20% CCR-CEB masonry was 400 hours lesser than that in building made of hollow cement blocks masonry. If air conditioning system is used to keep the indoor temperature below 28°C, the economy of 310,000 CFA francs (535 USD) is made every year on energy consumption for cooling in the model building made of 20% CCR-CEB masonry, corresponding to 9.6% less, with respect to that made of hollow cement blocks masonry.
基金Funded by the National Natural Science Foundation of China(No.51106161)the National Hi-Tech Research and Development Program of China(No.2012AA053003)the Guangdong Province and Chinese Academy of Sciences Comprehensive Strategic Cooperation Projects(2012B091100263)
文摘We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of Ca Cl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power（SCP） at 5 min adsorption time can reach as high as 0.19 g·g^-1 and 793.9 W·kg^-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.Key words： biomass material; adsorption system; ammonia; calcium chloride; activated carbon
文摘Micro-pored CA6 -MA lightweight material with CAM： MA mass ratio of 7：3 was prepared using Al（OH） 3, MgCO3 and CaCO3 as starting materials, and anthracite. sweet potato starch and anthracite ＋ sweet potato starch as pore forming agent （PFA） with an addition of 10 mass%, 20 mass% and 30 mass%, respectively. The starting materials were dry mixed, wet co-milled in a ball mill for 1 h. slip cast into cylindrical specimens with a diameter of 60 ram. and then calcined at 1 450 ℃ for 3 h. With the increase of PFA addition,, apparent porosity increases, and bulk density decreases. The influence of different PFAs on properties of the micro-pored LW CAM -MA aggregate was investigated. The achieved CAM - MA, by adding 30% sweet potato starch, has a porosity of 76. 8%, bulk density of 0. 78 g · cm^ - 3 and median pore size of 1.90 μm.
文摘Mineral trioxide aggregate (MTA) cement is an attractive material in endodontic dentistry. The purpose of this study was to produce calcium silicate, which is a major component of MTA, from waste materials. A dental alginate impression gel and used chalks were selected and mixed in a suitable ratio (Code: EXP). As a control, CaCO3 and a commercial diatomite were used (Code: CON). Each powder was heated to 850。C and 1000。C, and then kneaded with water. TG-DTA, compressive tests, SEM observations, elemental mapping analyses, and XRD analyses were performed. TG-DTA indicated that weight reduction of CaCO3 started at 600。C, and it completely decomposed on heating at 850。C. The strength was affected by the temperature. After heating, CaCO3 was transformed into CaO and/or Ca2SiO4, and Ca(OH)2 was formed by mixing with water. There were no differences between EXP and CON. These data suggested that recycled wastes might be promising MTA sources.
文摘Eggshell powder is a powdered product that is made from discarded eggshells. It is rich in inorganic salts and a small number of organic substances. Aliphatic polyester is one of the most promising polymer materials at present. Aliphatic polyester has not only a wide range of sources, but also excellent biodegradability and biocompatibility. Three kinds of aliphatic polyester composites were mixed with PCL, PBS, PHA, PLA and Ag powder as raw materials through solution reinforcement by eggshell powder. The thermal properties and structures of the three materials were analyzed and characterized by differential scanning calorimetry and scanning electron microscopy. DSC and SEM were used to analyze and characterize the thermal properties and structures of the three composites. The experimental results show that the GTT(glass-transition temperature) are 91.9°C, 89.3°C, and 87.2°C, the melting points are all greater than 92°C, and the enthalpy changes are respectively -37.8J/g, -23.9J/g, -22.2 J/g,. Among them, the composite material of PCL, PBS and eggshell powder, and Ag powder has excellent performance, showing good thermal performance and thermal stability. Moreover, the production and utilization of eggshell powder, turning waste into wealth, has important economic value for the sustainable development of circular ecology.
文摘In this manuscript, we describe the novel method for preparing the microcapsules containing α-tocopherol oil droplets as the first core material, calcium chloride powder as the second core material and the fine water droplets as the third core material by the interfacial condensation reaction between hydroxyl propyl methyl cellulose and tannic acid. The interfacial condensation reaction was performed between hydroxyl propyl methyl cellulose dissolved in the continuous water phase and tannic acid dissolved in the inner fine water droplets as the third core material. The calcium chloride powder as the second core material was dispersed in the α-tocopherol oil droplet as the first core material beforehand. The α-tocopherol oil containing the second and the third core materials was dispersed in the continuous water phase to form the [(S + W)/O/W] emulsion. The α-tocopherol oil as the first core material was microencapsulated satisfactorily and the contents of the second core material were increased with the concentration of stearic acid as the oil soluble stabilizer. The mechanical strength of microcapsules increased with the concentration of hydroxyl propyl methyl cellulose. Thermal energy could be released by breaking the microcapsules in water and by dissolving calcium chloride in the continuous water phase.
基金supported by the National Natural Science Foundation of China(Nos.42077185,U22A20591)the Sichuan Science and Technology Program for Distinguished Young Scholars(Nos.2022JDJQ0010,2022ZYD0040)+1 种基金the National Key Research and Development Program of China(No.2020YFC1808300)the Research Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(No.SKLGP2020Z002)。
文摘Degradation of nitrobenzene(NB)via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation.However,the poor stability of H2O2limits the application of traditional Fenton reactions in soil and groundwater due to the transportation risks of H_(2)O_(2).In this study,we synthesized a controlled release nano calcium peroxide(n CP)by coating it with polydopamine(PDA)as a solid H2O2to construct a Fe(Ⅱ)/PDA@n CP Fenton-like system for contaminants degradation.The phenolquinone transformations of catechol groups on the PDA surface facilitated the Fe(Ⅱ)/Fe(Ⅲ)cycle,resulting in enhanced generation of hydroxyl radicals(HO·)and effective long-term degradation of NB.Moreover,the PDA shell modulated the n CP decomposition rate and inhibited sharp p H fluctuations,and the NB removal efficiency was achieved up to 96.8%at p H ranging from 3.0 to 9.0.This study demonstrated the promising application potential of PDA@n CP as a solid-controlled release H2O2source in Fenton-like system for groundwater contamination remediation.
基金This work was supported by the National Natural Science Foun-dation of China(No.52174273)the Basic Science Center Project for National Natural Science Foundation of China(No.72088101)+1 种基金the Postdoctoral Science Foundation of China(No.2021TQ0370)the Science and Technology Innovation Program of Hunan Pro-vince(No.2021RC2003).
文摘Coal fly ash is a typical secondary aluminum/silicon resource.The preparation of zeolite-type absorbent is a potential way for its value-added utilization,while the purity and adsorption property of zeolite are limited due to the occurrence of side reactions in the synthesis process.In this study,a designated composite consisted of crystalline zeolites and amorphous calcium silicate hydrate was selected,which was direct synthesized from fly ash under conditions of a Ca/Si molar ratio of 0.8,an initial NaOH concentration of 0.5 mol/L,a hydrothermal temperature of 170℃and a liquid–solid ratio of 15 mL/g.The results indicated that this composite had superior adsorption property for a variety of heavy metals,which was based on the exchange of calcium and sodium ions in zeolites and calcium silicate hydrate.Its adsorption capacities for Pb^(2+),Ni^(2+),Cd^(2+),Zn^(2+),Cu^(2+)and Cr^(3+)attained 409.4,222.4,147.5,93.2,101.1 and 157.0 mg/g,respectively,in single solution with a pH of 4.5.After regulating the synthesis conditions,the transformation of amorphous calcium silicate hydrate into crystallized tobermorite weakened the adsorption capacity of the composite.Besides,due to the competitive adsorption in a multiple ions solution,the adsorption capacities for these heavy metals had a reduction.
基金supported by the National Key Research and Development Program of China from Ministry of Science and Technology(2016YFC1100502)Key Research Program of Frontier Sciences(QYZDJ-SSW-JSC031)from Chinese Academy of Sciences(CAS)+1 种基金Key Research and Development Program of Liaoning Province(2017105005)Shenyang Key R&D and Technology Transfer Program(Z17-7-023)。
文摘Magnesium(Mg^2+))ion plays important roles in biomineralization of bone,teeth and calcium carbonate skeletons.Herein,chicken eggshells mainly comprising of Mg-calcite nanocrystals(Mg/(Mg+Ca)2.0 mol.%)were used to fabricate biphasic calcium phosphate(BCP),a mixture of hydroxyapatite(HA)and p-tricalcium phosphate(p-TCP)nanocrystals,through hydrothermal reactions at 200℃for 24 h.Our results indicated thatβ-TCP nanocrystals formed through the ion-exchange reactions of Mg-calcite,while HA nanocrystals were mainly produced by dissolution-reprecipitation reactions on the surfaces of eggshell samples in the hydrothermal system.Mg substitution in calcite resulted in formation ofβ-TCP nanocrystals instead of HA crystals through ion-exchange reactions.BCP samples with different compositions(28.6-77.8 wt.%β-TCP)were produced by controlling particle sizes of eggshells for hydrothermal reactions.The larger particles lead to the larger proportion ofβ-TCP in the BCP composition.Therefore,Mg substitution and particle size had synergetic effects on the hydrothermal synthesis of BCP using chicken eggshells through balance of ion-exchange and dissolution-reprecipitation reactions.Cell culture results showed that the BCP products were non-cytotoxic to MC3 T3-E1 cells,which may be used for bone substitute materials in future.
文摘BACKGROUND The success rate of conservative endodontic management for root fracture varies greatly based on different methods used.It has been rarely reported that calcium silicate-based materials are applied in root fracture treatment.CASE SUMMARY A 38-year-old male patient presented with spontaneous pain from the upper left anterior teeth for 1 wk.The spontaneous pain was subsequently relieved,but pain on mastication persisted for 3 d.The patient had a dental trauma from a boxing match 15 years ago.Cone beam computed tomography showed that the maxillary left central incisor had oblique fracture lines and a radiolucent lesion around the fracture line.The tooth was diagnosed with an oblique root fracture with no healing and symptomatic apical periodontitis.In the following conservative endodontic management,the coronal and apical fragments of the canal both were chemo-mechanically prepared and obturated using a single cone gutta-percha with iRoot SP(Innovative BioCreamix Inc,Vancouver,Canada),a new calcium silicate-based bioceramic root canal sealer.At follow-ups at 1,6,12,and 24 mo,the patient was asymptomatic and the radiolucency around the fracture line was healing radiographically.CONCLUSION Conservative root canal treatment is an alternative treatment in some cases of oblique root fracture with no healing.The application of bioceramic sealers and single core obturation techniques may also be essential to obtain an excellent outcome.
