Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes...Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.展开更多
Aqueous alkali metal-ion batteries(AAMIBs)have been recognized as emerging electrochemical energy storage technologies for grid-scale applications owning to their intrinsic safety,cost-effectiveness,and environmental ...Aqueous alkali metal-ion batteries(AAMIBs)have been recognized as emerging electrochemical energy storage technologies for grid-scale applications owning to their intrinsic safety,cost-effectiveness,and environmental sustainability.However,the practical application of AAMIBs is still severely constrained by the tendency of aqueous electrolytes to freeze at low temperatures and decompose at high temperatures,limiting their operational temperature range.Considering the urgent need for energy systems with higher adaptability and resilience at various application scenarios,designing novel electrolytes via structure modulation has increasingly emerged as a feasible and economical strategy for the performance optimization of wide-temperature AAMIBs.In this review,the latest advancement of wide-temperature electrolytes for AAMIBs is systematically and comprehensively summarized.Specifically,the key challenges,failure mechanisms,correlations between hydrogen bond behaviors and physicochemical properties,and thermodynamic and kinetic interpretations in aqueous electrolytes are discussed firstly.Additionally,we offer forward-looking insights and innovative design principles for developing aqueous electrolytes capable of operating across a broad temperature range.This review is expected to provide some guidance and reference for the rational design and regulation of widetemperature electrolytes for AAMIBs and promote their future development.展开更多
Chemical hydrogen storage in organic materials is a promising method thanks to its high storage density,reversibility,and safety.However,the dehydrogenation process of organic materials requires high temperatures due ...Chemical hydrogen storage in organic materials is a promising method thanks to its high storage density,reversibility,and safety.However,the dehydrogenation process of organic materials requires high temperatures due to their unfavorable thermodynamic properties.This study proposes a strategy to design a new type of hydrogen storage materials,i.e.,alkali metal pyridinolate/piperidinolate pairs,by combining the effects of a heteroatom and an alkali metal in one molecule to achieve suitable dehydrogenation thermodynamics along with high hydrogen storage capacities.These air-stable compounds can be synthesized using low-cost reactants and water as a green solvent.Thermodynamic predictions indicate that enthalpy changes of dehydrogenation(ΔH_(d))can be significantly reduced to the optimal range for efficient hydrogen release,exemplified by lithium 2-piperidinolate with a 5.6 wt%hydrogen capacity and a suitableΔH_(d)of 32.2 kJ/mol-H_(2).Experimental results obtained using sodium systems validate the computational predictions,demonstrating reversible hydrogen storage even below 100℃.The superior hydrogen desorption performance of alkali metal piperidinolates could be attributed to their suitableΔH_(d)induced by the combined effect of ring nitrogen and metal substitution on their structures.This study not only reports new low-cost hydrogen storage materials but also provides a rational design strategy for developing metalorganic compounds possessing high hydrogen capacities and suitable thermodynamics for efficient hydrogen storage.展开更多
Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries.However,achieving the balance among low cost,high waste recycling rat...Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries.However,achieving the balance among low cost,high waste recycling rates,and adequate strength remains a significant challenge for cemented rockfill.This study used a composite alkali activator to activate gangue cemented rockfill.The compressive strength,scanning electron microscopy,energy dispersive spectrometer,mercury intrusion porosimetry,X-ray diffraction,and thermogra-vimetric tests were carried out to investigate the effect of the composite alkali activator proportion on the compressive strength,micro-structure,and composition of the cemented rockfill.The calcium silicate hydrate(C–S–H)molecular model of cemented rockfill was con-structed to explore the fracture evolution of the nucleated molecular structure under tension.The results show that compressive strength initially increased and then decreased with the activator proportion,the optimal activator proportion of 1:2 resulted in a 31.25%increase in strength at 3 d.This reasonable activator proportion strengthens the pozzolanic effect of gangue,and consumes more calcium hydroxide to inhibit its agglomeration,ultimately achieving the densification of microstructure.The activator proportion inevitably substitutes calcium ions with sodium ions in the C–S–H molecular model.The 12%substitution of calcium ions increases the adhesion between silicon chain layers,which is beneficial to the interlayer stress transfer.This work proposes a method for preparing low-cost cemented rockfill from al-kali-activated gangue,which can be used for solid waste recycling and reducing cement consumption to achieve low-carbon goals.展开更多
Granite residual soil (GRS) is a type of weathering soil that can decompose upon contact with water, potentially causing geological hazards. In this study, cement, an alkaline solution, and glass fiber were used to re...Granite residual soil (GRS) is a type of weathering soil that can decompose upon contact with water, potentially causing geological hazards. In this study, cement, an alkaline solution, and glass fiber were used to reinforce GRS. The effects of cement content and SiO_(2)/Na2O ratio of the alkaline solution on the static and dynamic strengths of GRS were discussed. Microscopically, the reinforcement mechanism and coupling effect were examined using X-ray diffraction (XRD), micro-computed tomography (micro-CT), and scanning electron microscopy (SEM). The results indicated that the addition of 2% cement and an alkaline solution with an SiO_(2)/Na2O ratio of 0.5 led to the densest matrix, lowest porosity, and highest static compressive strength, which was 4994 kPa with a dynamic impact resistance of 75.4 kN after adding glass fiber. The compressive strength and dynamic impact resistance were a result of the coupling effect of cement hydration, a pozzolanic reaction of clay minerals in the GRS, and the alkali activation of clay minerals. Excessive cement addition or an excessively high SiO_(2)/Na2O ratio in the alkaline solution can have negative effects, such as the destruction of C-(A)-S-H gels by the alkaline solution and hindering the production of N-A-S-H gels. This can result in damage to the matrix of reinforced GRS, leading to a decrease in both static and dynamic strengths. This study suggests that further research is required to gain a more precise understanding of the effects of this mixture in terms of reducing our carbon footprint and optimizing its properties. The findings indicate that cement and alkaline solution are appropriate for GRS and that the reinforced GRS can be used for high-strength foundation and embankment construction. The study provides an analysis of strategies for mitigating and managing GRS slope failures, as well as enhancing roadbed performance.展开更多
The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are...The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are required in the process of plant supplementing light,arrow-band emitting phosphors are applied to backlight displays,etc.In this work,a Bi^(3+)-activated blue phosphor was obtained in a symmetrical and co mpact crystal structure of Gd3Sb07(GSO).Then,the co-doping strategy of alkali metal ions(Li^(+),Na^(+),and K^(+))was used to optimize the performance.The result shows that the photoluminescence intensity is increased by 2.1 times and 1.3 times respectively by introducing Li~+and K^(+)ions.Not only that,it also achieves narrow-band emitting with the full width of half-maximum(FWHM)reaching 42 nm through Na^(+)doping,and its excitation peak position also shifts from 322 to 375 nm,which can be well excited by near-ultraviolet(NUV)light emitting diode(LED)chips(365 nm).Meanwhile,the electroluminescence spectrum of GSO:0.6 mol%Bi^(3+),3 wt%Na^(+)matches up to 93.39%of the blue part of the absorption spectrum of chlorophyll a.In summary,the Bi^(3+)-activated blue phosphor reported in this work can synchronously meet the requirements of plant light replenishment and field emission displays.展开更多
The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in...The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.展开更多
Alkali treatments with three concentrations were used to modify a microarc-oxidized(MAO) coating on titanium alloy surface in order to further improve its surface bioactivity. Morphology, chemical compositions and pha...Alkali treatments with three concentrations were used to modify a microarc-oxidized(MAO) coating on titanium alloy surface in order to further improve its surface bioactivity. Morphology, chemical compositions and phase constitues, roughness, contact angle and apatite induction of the alkali-treated coatings were studied and compared. Scanning electron microscope(SEM) was applied to observe the morphologies, X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) were used to detect the phase constitutes and chemical compositions, a surface topography profilometer was used to analyze the surface roughness, and contact angle was measured by liquid drop method. Alkali treatements result in the formation of Na2Ti6O13 and Na2Ti3O7 phase on the MAO coating, which leads to the increase of surface roughness and the decrease of contact angle. Experimental results showed that the apatite induction of the alkali-treated coatings was dependent on the applied alkali concentrations during treatments, and Na+concentration can promote the formation of apatite phase.展开更多
We read with great interest the investigations conducted by Pourakbar et al.(2024)on the“Stabilization of clay soil using alkali-activated sewage sludge.”The authors have investigated the feasibility of utilizing al...We read with great interest the investigations conducted by Pourakbar et al.(2024)on the“Stabilization of clay soil using alkali-activated sewage sludge.”The authors have investigated the feasibility of utilizing alkali-activated sewage sludge(AASS)as a binder for stabilizing the clayey soil.Sewage sludge(SS)in varying proportions of 1.5%,2%,2.5%,3.5%,and 4.5%was utilized to prepare geopolymer binders using sodium and potassium-based alkali activators.Furthermore,unconfined compressive strength(UCS)and direct shear tests were conducted to examine the strength development of clayey soil stabilized with AASS.While the study presented some intriguing results,we have identified critical concerns regarding(i)the selection of SS as a precursor for alkali activation,(ii)technical inconsistencies associated with the compaction characteristics and microstructural analysis,and(iii)the feasibility of the proposed methodology for practical applications.Through our discussion,we seek to highlight these issues and provide constructive feedback to advance the understanding of alkali activation processes and their implications for soil stabilization.展开更多
The soot emitted during the operation of diesel engine exhaust seriously threatens the human health and environment,so treating diesel engine exhaust is critical.At present,the most effective method for eliminating so...The soot emitted during the operation of diesel engine exhaust seriously threatens the human health and environment,so treating diesel engine exhaust is critical.At present,the most effective method for eliminating soot particles is post-treatment technology.Preparation of economically viable and highly active soot combustion catalysts is a pivotal element of post-treatment technology.In this study,different single-metal oxide catalysts with fibrous structures and alkali metal-modified hollow nanotubular Mn-based oxide catalysts were synthesized using centrifugal spinning method.Activity evaluation results showed that the manganese oxide catalyst has the best catalytic activity among the prepared single-metal oxide catalysts.Further research on alkali metal modification showed that doping alkali metals is beneficial for improving the oxidation state of manganese and generating a large number of reactive oxygen species.Combined with the structural effect brought by the hollow nanotube structure,the alkali metal-modified Mn-based oxide catalysts exhibit superior catalytic performance.Among them,the Cs-modified Mn-based oxide catalyst exhibits the best catalytic performance because of its rich active oxygen species,excellent NO oxidation ability,abundant Mn^(4+)ions(M^(n4)+/Mn^(n+)=64.78%),and good redox ability.The T_(10),T_(50),T_(90),and CO_(2)selectivity of the Cs-modified Mn-based oxide catalyst were 267°C,324°C,360°C,and 97.8%,respectively.展开更多
An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights...An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights of the pristine PLLA(crystalline part),single stem,and single cluster were determined by gel permeation chromatography(GPC)according to their evolution during alkali hydrolysis.The maximum-folding-number(in a single cluster)and minimum-cluster-number(in one polymer chain)were obtained using these molecular weights.With the help of two numbers,the chain folding and traversing during the melt crystallization process(at 120℃)of PLLA can be described as follows.Statistically,in a single polymer chain,there are at least 2 clusters consisting of up to 6.5 stems in each of them,while the rest of the polymer chain contributes to amorphous regions.Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.展开更多
Sulfur trioxide(SO_(3))as a condensable particle matter has a significant influence on atmospheric visibility,which easily arouses formation of haze.It is imperative to control the SO_(3)emission from the industrial f...Sulfur trioxide(SO_(3))as a condensable particle matter has a significant influence on atmospheric visibility,which easily arouses formation of haze.It is imperative to control the SO_(3)emission from the industrial flue gas.Three commonly used basic absorbents,including Ca(OH)_(2),MgO and NaHCO_(3)were selected to explore the effects of temperature,SO_(2)concentration on the SO_(3)absorption,and the reaction mechanism of SO_(3)absorption was further illustrated.The suitable reaction temperature for various absorbents were proposed,Ca(OH)_(2)at the high temperatures above 500°C,MgO at the low temperatures below 320°C,and NaHCO_(3)at the temperature range of 320–500°C.The competitive absorption between SO_(2)and SO_(3)was found that the addition of SO_(2)reduced the SO_(3)absorption on Ca(OH)_(2)and NaHCO_(3),while had no effect on MgO.The order of the absorption selectivity of SO_(3)follows MgO,NaHCO_(3)and Ca(OH)_(2)under the given conditions in this work.The absorption process of SO_(3)on NaHCO_(3)follows the shrinking core model,thus the absorption reaction continues until NaHCO_(3)was exhausted with the utilization rate of nearly 100%.The absorption process of SO_(3)on Ca(OH)_(2)and MgO follows the grain model,and the dense product layer hinders the further absorption reaction,resulting in low utilization of about 50%for Ca(OH)_(2)and MgO.The research provides a favorable support for the selection of alkaline absorbent for SO_(3)removal in application.展开更多
Co-associated rare earth elements(lanthanide and yttrium,REY)in coal and its by-products have been considered important potential nontraditional rare earth sources.In this study,a coal gangue sample collected from a c...Co-associated rare earth elements(lanthanide and yttrium,REY)in coal and its by-products have been considered important potential nontraditional rare earth sources.In this study,a coal gangue sample collected from a coal processing plant in Jinsha County of Guizhou Province,southwest China,was used as the research object.The content,modes of occurrence,and extraction(acid leaching after pretreatment of selective grinding,tailings discarding,and alkali roasting)of REY from the sample were analyzed.The result shows that the content of REY(1038.26μg/g)in pyrite and quartz is low but mainly enriched in kaolinite.Under the following conditions of a filling ratio of 40%(grinding media steel ball)and grinding time of 8 min,selective grinding pretreatment is applied to achieve 176.95μg/g(yield 24.08%)and 1104.93μg/g(yield 75.92%)of REY in+2 mm and-2 mm fractions,respectively.Thus,the-2 mm coal gangue fraction is selected,used as the feed,and roasted and leached with HCl.When Na_(2)CO_(3)and NaCl are separately used as roasting activators,the REY leaching ratios are 91.41%and 68.88%,respectively,under the optimum conditions.The contents of REY in the final leachate are 1010.02 and 761.08μg/g when Na_(2)CO_(3)and NaCl are used,respectively.The two REY contents are relatively higher than the impurity ions in the leachate,which facilitates further REY separation.The mechanism study reveals that high-temperature roasting increases the pore size and the total pore area of the gangue,which promotes leachate penetration and improves reaction efficiency.In addition,roasting facilitates the reaction between the sodium salt activator and kaolinite and other aluminosilicate minerals in the coal gangue to generate soluble salts,thus releasing REY into the solution.The appropriate roasting temperature transforms the activator into a molten state.Thus,the reaction between coal gangue and activator is a solid-liquid reaction rather than a solid-solid reaction,which improves the efficiency of the chemical reaction.展开更多
Alkali metal batteries(AMBs)have undergone substantial development in portable devices due to their high energy density and durable cycle performance.However,with the rising demand for smart wearable electronic device...Alkali metal batteries(AMBs)have undergone substantial development in portable devices due to their high energy density and durable cycle performance.However,with the rising demand for smart wearable electronic devices,a growing focus on safety and durability becomes increasingly apparent.An effective strategy to address these increased requirements involves employing the quasi-solid gel electrolytes(QSGEs).This review focuses on the application of QSGEs in AMBs,emphasizing four types of gel electrolytes and their influence on battery performance and stability.First,self-healing gels are discussed to prolong battery life and enhance safety through self-repair mechanisms.Then,flexible gels are explored for their mechanical flexibility,making them suitable for wearable devices and flexible electronics.In addition,biomimetic gels inspired by natural designs are introduced for high-performance AMBs.Furthermore,biomass materials gels are presented,derived from natural biomaterials,offering environmental friendliness and biocompatibility.Finally,the perspectives and challenges for future developments are discussed in terms of enhancing the ionic conductivity,mechanical strength,and environmental stability of novel gel materials.The review underscores the significant contributions of these QSGEs in enhancing AMBs performance,including increased lifespan,safety,and adaptability,providing new insights and directions for future research and applications in the field.展开更多
The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping...The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping on Pt-based catalysts in CO_(2)-ODH reactions.The optimized 0.1 KPt/S-1 catalyst achieved a high propane conversion of 48.3%,propylene selectivity of 85.5%,and CO_(2)conversion of 19.1%at a low temperature of 500℃with the Pt loading of 0.2 wt%and K loading of 0.1 wt%respectively.Characterization techniques,including high-resolution transmission electron microscope(HR-TEM),CO-diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),X-ray absorption fine structure(XAFS),and X-ray Photoelectron Spectroscopy(XPS),revealed that the doping of K with Pt led to a strong interaction between potassium and platinum(Pt-KO_(x)cluster).This interaction resulted in a reduction of Pt particle size and a local enrichment of electron density around Pt atoms.These structural modifications improved the anchoring of Pt nanoparticles and enhanced Pt atom dispersion,thereby enhancing the activity of the catalyst and minimizing side reactions.Additionally,pyridine infrared(Py-IR)and temperature-programmed desorption(TPD)studies demonstrated that the prepared0.1 KPt/S-1 catalyst exhibited optimal acidity,which promoted C–H activation and facilitated the efficient adsorption and activation of CO_(2).These dual effects significantly lowered the activation energy for CO_(2)-ODH,enabling efficient dehydrogenation to propylene at a lower temperature of 500℃.This work highlights the critical role of alkali metal doping in modifying the electronic properties of Pt and optimizing catalyst acidity,which collectively contribute to the enhanced performance of the 0.1 KPt/S-1 catalyst.These findings offer valuable insights into the mechanistic pathway of CO_(2)-ODH and provide a foundation for the rational design of high-performance dehydrogenation catalysts.展开更多
Chitin,distinguished by its nitrogen-rich acetamido and amino groups,imparts a distinctive cationic nature,enabling chitin to have indispensable features in various applications.Despite its significant promise in the ...Chitin,distinguished by its nitrogen-rich acetamido and amino groups,imparts a distinctive cationic nature,enabling chitin to have indispensable features in various applications.Despite its significant promise in the textile industry,particularly for sustainable and functional fabric applications,the practical utilization of chitin fibers remains constrained by insufficient mechanical strength.The degree of deacetylation(DD),a key molecular-level structural determinant,has not been adequately addressed in previous studies despite its critical role in influencing chitin properties across multiple scales.In this study,a deacetylation-mediated design strategy was used to achieve enhanced mechanical performance coupled with multifunctional efficacy using an aqueous KOH/urea solution dissolution system.We prepared a series of deacetylated chitins with different DD values and systematically studied the effect of deacetylation on the multiple-scale structure of regenerated fibers,such as intermolecular interactions and chain orientation at the molecular level,and the aggregation behavior of chitin nanofibers within the gel-state and dried fibers at the micro/nano scale.To achieve an enhanced mechanical performance coupled with multifunctional efficacy by relying on an aqueous KOH/urea solution dissolution system.Moreover,deacetylation enhances intermolecular interactions,resulting in densified internal structures and improved fiber orientation.Concomitantly,it augmented the antimicrobial functionality of the fibers.This deacetylation-mediated design strategy provides a deeper understanding of the structure and properties of regenerated chitin and advances the utility of chitin in strong and sustainable fibers.展开更多
Recent advancements have led to the synthesis of various new metal-containing explosives,particularly energetic metal-organic frameworks(EMOFs),which feature high-energy ligands within well-ordered crystalline structu...Recent advancements have led to the synthesis of various new metal-containing explosives,particularly energetic metal-organic frameworks(EMOFs),which feature high-energy ligands within well-ordered crystalline structures.These explosives exhibit significant advantages over traditional compounds,including higher density,greater heats of detonation,improved mechanical hardness,and excellent thermal stability.To effectively evaluate their detonation performance,it is crucial to have a reliable method for predicting detonation heat,velocity,and pressure.This study leverages experimental data and outputs from the leading commercial computer code to identify suitable decomposition pathways for different metal oxides,facilitating straightforward calculations for the detonation performance of alkali metal salts,and metal coordination compounds,along with EMOFs.The new model enhances predictive reliability for detonation velocities,aligning more closely with experimental results,as evi-denced by a root mean square error(RMSE)of 0.68 km/s compared to 1.12 km/s for existing methods.Furthermore,it accommodates a broader range of compounds,including those containing Sr,Cd,and Ag,and provides predictions for EMOFs that are more consistent with computer code outputs than previous predictive models.展开更多
Noteworthy challenges such as severe side reactions,interfacial instability,and dendrite growth have plagued rechargeable alkali metal batteries for a long time.Alleviating the plight necessitates innovative membranes...Noteworthy challenges such as severe side reactions,interfacial instability,and dendrite growth have plagued rechargeable alkali metal batteries for a long time.Alleviating the plight necessitates innovative membranes capable of modulating ion transport and establishing stable interfaces.The exploration of implemented membranes with thermal/mechanical and electrochemical stability is crucial for achieving high-performance and safe alkali metal batteries.Crystalline covalent organic framework(COF)membranes have emerged as promising materials for next-generation energy storage systems due to their tunable porosity and exceptional physicochemical properties.This review specifically examines the critical role of COF membranes in enabling sustainable alkali metal(Li/Na/K)batteries,with a particular focus on design principles,performance advantages,and key challenges of COF membranes.The discussion emphasizes structure-property relationships specifically relevant to rechargeable battery applications,supported by recent decades of research.Impressively,this mini review further identifies three critical research frontiers:reticular chemistry-guided materials design,multifunctional composite architectures,and in-situ characterization techniques.This targeted analysis provides actionable insights for developing COF membranes that address the fundamental limitations of current alkali metal battery technologies.展开更多
A pre-reduction sintering process with flue gas recirculation(PSP_(fsg)-FGR)was developed to mitigate alkalis harm to the blast furnace and reduce the flue gas emission in the whole ironmaking process.The results indi...A pre-reduction sintering process with flue gas recirculation(PSP_(fsg)-FGR)was developed to mitigate alkalis harm to the blast furnace and reduce the flue gas emission in the whole ironmaking process.The results indicated that the pre-reduction sintering process(PSP)can effectively remove 58.02%of K and 30.68%of Na from raw mixtures and improve yield and tumbler index to 74.40%and 68.69%,respectively.Moreover,PSP was conducive to reducing NO_(x) and SO_(2)emissions and simultaneously increasing CO content in flue gas.Circulating CO-containing flue gas to sintering bed effectively recycled CO and further improved K and Na removal ratio to 74.11%and 32.92%,respectively.Microstructural analysis revealed that the pre-reduced sinter mainly consisted of magnetite,wustite and a small quantity of metallic iron,and very few silicate glass phase was also formed.This process can simultaneously realize alkali metal elements removal as well as flue gas emission reduction from the integrated ironmaking process.展开更多
The implementation of embedded selective catalytic reduction(SCR)denitration in chain grate during iron ore pelletizing process obviates additional flue gas heating.However,the influence of gas components and alkali m...The implementation of embedded selective catalytic reduction(SCR)denitration in chain grate during iron ore pelletizing process obviates additional flue gas heating.However,the influence of gas components and alkali metal on SCR denitration requires attention.The SCR denitration behavior in the preheating section of chain grate was investigated,and the combined influence mechanisms of H_(2)O(g),SO_(2),and potassium were revealed.The results show that the presence of H_(2)O(g)and SO_(2) in the flue gas decreases the NO conversion rate of the catalyst from 96.3%to 79.5%,while potassium adsorbed on the catalyst surface further reduces the NO conversion rate to 74.1%.H_(2)O(g),SO_(2),and potassium in the flue gas form sulfate and potassium salt on the catalyst surface,blocking the pore structure,thereby decreasing the gas adsorption capacity of the catalyst.Moreover,SO_(2) and potassium engage in competitive adsorption and reaction with NH_(3) and NO at the active sites on the catalyst surface,reducing the content and activity of the catalyst effective component.Increasing the flue gas temperature can promote the decomposition of ammonium sulfate and ammonium bisulfate on the catalyst surface,but it has little effect on potassium.Additionally,potassium will exacerbate sulfur poisoning of the catalyst.Hence,the embedded SCR denitration process requires electrostatic precipitation to eliminate the adverse impacts of potassium and thermal regime optimization to raise flue gas temperature to 350℃,thereby increasing NO conversion rate exceeding 85%.展开更多
基金Supported by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.
基金supported by the National Natural Science Foundation of China(52002297)National Key R&D Program of China(2022VFB2404800)+1 种基金Wuhan Yellow Crane Talents Program,China Postdoctoral Science Foundation(No.2024M752495)the Postdoctoral Fellowship Program of CPSF(No.GZB20230552).
文摘Aqueous alkali metal-ion batteries(AAMIBs)have been recognized as emerging electrochemical energy storage technologies for grid-scale applications owning to their intrinsic safety,cost-effectiveness,and environmental sustainability.However,the practical application of AAMIBs is still severely constrained by the tendency of aqueous electrolytes to freeze at low temperatures and decompose at high temperatures,limiting their operational temperature range.Considering the urgent need for energy systems with higher adaptability and resilience at various application scenarios,designing novel electrolytes via structure modulation has increasingly emerged as a feasible and economical strategy for the performance optimization of wide-temperature AAMIBs.In this review,the latest advancement of wide-temperature electrolytes for AAMIBs is systematically and comprehensively summarized.Specifically,the key challenges,failure mechanisms,correlations between hydrogen bond behaviors and physicochemical properties,and thermodynamic and kinetic interpretations in aqueous electrolytes are discussed firstly.Additionally,we offer forward-looking insights and innovative design principles for developing aqueous electrolytes capable of operating across a broad temperature range.This review is expected to provide some guidance and reference for the rational design and regulation of widetemperature electrolytes for AAMIBs and promote their future development.
基金partially supported by the National Key R&D Program of China(2023YFE0198900)support provided by the National Natural Science Foundation of China(52171226,22309174)。
文摘Chemical hydrogen storage in organic materials is a promising method thanks to its high storage density,reversibility,and safety.However,the dehydrogenation process of organic materials requires high temperatures due to their unfavorable thermodynamic properties.This study proposes a strategy to design a new type of hydrogen storage materials,i.e.,alkali metal pyridinolate/piperidinolate pairs,by combining the effects of a heteroatom and an alkali metal in one molecule to achieve suitable dehydrogenation thermodynamics along with high hydrogen storage capacities.These air-stable compounds can be synthesized using low-cost reactants and water as a green solvent.Thermodynamic predictions indicate that enthalpy changes of dehydrogenation(ΔH_(d))can be significantly reduced to the optimal range for efficient hydrogen release,exemplified by lithium 2-piperidinolate with a 5.6 wt%hydrogen capacity and a suitableΔH_(d)of 32.2 kJ/mol-H_(2).Experimental results obtained using sodium systems validate the computational predictions,demonstrating reversible hydrogen storage even below 100℃.The superior hydrogen desorption performance of alkali metal piperidinolates could be attributed to their suitableΔH_(d)induced by the combined effect of ring nitrogen and metal substitution on their structures.This study not only reports new low-cost hydrogen storage materials but also provides a rational design strategy for developing metalorganic compounds possessing high hydrogen capacities and suitable thermodynamics for efficient hydrogen storage.
基金supported by the Key Research and Development Special Tasks of Xinjiang,China (No.2022B01051-2)the National Natural Science Foundation of China (Nos.U23B2091,42372328,and 52478253)+1 种基金the Natural Science Foundation of Jiangsu Province,China (No.BK20240209)the Science and Technology Program Special Fund of Jiangsu Province (Frontier Leading Technology Basic Research) Major projects,China (No.BK 20222004)
文摘Using cemented rockfill to replace coal pillars offers an effective solution for reducing solid waste while ensuring the safety of gob-side entries.However,achieving the balance among low cost,high waste recycling rates,and adequate strength remains a significant challenge for cemented rockfill.This study used a composite alkali activator to activate gangue cemented rockfill.The compressive strength,scanning electron microscopy,energy dispersive spectrometer,mercury intrusion porosimetry,X-ray diffraction,and thermogra-vimetric tests were carried out to investigate the effect of the composite alkali activator proportion on the compressive strength,micro-structure,and composition of the cemented rockfill.The calcium silicate hydrate(C–S–H)molecular model of cemented rockfill was con-structed to explore the fracture evolution of the nucleated molecular structure under tension.The results show that compressive strength initially increased and then decreased with the activator proportion,the optimal activator proportion of 1:2 resulted in a 31.25%increase in strength at 3 d.This reasonable activator proportion strengthens the pozzolanic effect of gangue,and consumes more calcium hydroxide to inhibit its agglomeration,ultimately achieving the densification of microstructure.The activator proportion inevitably substitutes calcium ions with sodium ions in the C–S–H molecular model.The 12%substitution of calcium ions increases the adhesion between silicon chain layers,which is beneficial to the interlayer stress transfer.This work proposes a method for preparing low-cost cemented rockfill from al-kali-activated gangue,which can be used for solid waste recycling and reducing cement consumption to achieve low-carbon goals.
基金the support provided by the National Natural Science Foundation of China(Grant Nos.52278336 and 42302032)Guangdong Basic and Applied Research Foundation(Grant Nos.2023B1515020061).
文摘Granite residual soil (GRS) is a type of weathering soil that can decompose upon contact with water, potentially causing geological hazards. In this study, cement, an alkaline solution, and glass fiber were used to reinforce GRS. The effects of cement content and SiO_(2)/Na2O ratio of the alkaline solution on the static and dynamic strengths of GRS were discussed. Microscopically, the reinforcement mechanism and coupling effect were examined using X-ray diffraction (XRD), micro-computed tomography (micro-CT), and scanning electron microscopy (SEM). The results indicated that the addition of 2% cement and an alkaline solution with an SiO_(2)/Na2O ratio of 0.5 led to the densest matrix, lowest porosity, and highest static compressive strength, which was 4994 kPa with a dynamic impact resistance of 75.4 kN after adding glass fiber. The compressive strength and dynamic impact resistance were a result of the coupling effect of cement hydration, a pozzolanic reaction of clay minerals in the GRS, and the alkali activation of clay minerals. Excessive cement addition or an excessively high SiO_(2)/Na2O ratio in the alkaline solution can have negative effects, such as the destruction of C-(A)-S-H gels by the alkaline solution and hindering the production of N-A-S-H gels. This can result in damage to the matrix of reinforced GRS, leading to a decrease in both static and dynamic strengths. This study suggests that further research is required to gain a more precise understanding of the effects of this mixture in terms of reducing our carbon footprint and optimizing its properties. The findings indicate that cement and alkaline solution are appropriate for GRS and that the reinforced GRS can be used for high-strength foundation and embankment construction. The study provides an analysis of strategies for mitigating and managing GRS slope failures, as well as enhancing roadbed performance.
基金Project supported by the Key R&D Projects in Hunan Province(2021SK2047,2022NK2044)Science and Technology Innovation Program of Hunan Province(2022WZ1022)Superior Youth Project of the Science Research Project of Hunan Provincial Department of Education(22B0211)。
文摘The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are required in the process of plant supplementing light,arrow-band emitting phosphors are applied to backlight displays,etc.In this work,a Bi^(3+)-activated blue phosphor was obtained in a symmetrical and co mpact crystal structure of Gd3Sb07(GSO).Then,the co-doping strategy of alkali metal ions(Li^(+),Na^(+),and K^(+))was used to optimize the performance.The result shows that the photoluminescence intensity is increased by 2.1 times and 1.3 times respectively by introducing Li~+and K^(+)ions.Not only that,it also achieves narrow-band emitting with the full width of half-maximum(FWHM)reaching 42 nm through Na^(+)doping,and its excitation peak position also shifts from 322 to 375 nm,which can be well excited by near-ultraviolet(NUV)light emitting diode(LED)chips(365 nm).Meanwhile,the electroluminescence spectrum of GSO:0.6 mol%Bi^(3+),3 wt%Na^(+)matches up to 93.39%of the blue part of the absorption spectrum of chlorophyll a.In summary,the Bi^(3+)-activated blue phosphor reported in this work can synchronously meet the requirements of plant light replenishment and field emission displays.
文摘The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.
基金Projects(51172050,51102060,51302050)supported by the National Natural Science Foundation of ChinaProject(HIT.ICRST.2010009)supported by the Fundamental Research Funds for Central Universities,ChinaProject(HIT.NSRIF.2014129)supported by the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology,China
文摘Alkali treatments with three concentrations were used to modify a microarc-oxidized(MAO) coating on titanium alloy surface in order to further improve its surface bioactivity. Morphology, chemical compositions and phase constitues, roughness, contact angle and apatite induction of the alkali-treated coatings were studied and compared. Scanning electron microscope(SEM) was applied to observe the morphologies, X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) were used to detect the phase constitutes and chemical compositions, a surface topography profilometer was used to analyze the surface roughness, and contact angle was measured by liquid drop method. Alkali treatements result in the formation of Na2Ti6O13 and Na2Ti3O7 phase on the MAO coating, which leads to the increase of surface roughness and the decrease of contact angle. Experimental results showed that the apatite induction of the alkali-treated coatings was dependent on the applied alkali concentrations during treatments, and Na+concentration can promote the formation of apatite phase.
文摘We read with great interest the investigations conducted by Pourakbar et al.(2024)on the“Stabilization of clay soil using alkali-activated sewage sludge.”The authors have investigated the feasibility of utilizing alkali-activated sewage sludge(AASS)as a binder for stabilizing the clayey soil.Sewage sludge(SS)in varying proportions of 1.5%,2%,2.5%,3.5%,and 4.5%was utilized to prepare geopolymer binders using sodium and potassium-based alkali activators.Furthermore,unconfined compressive strength(UCS)and direct shear tests were conducted to examine the strength development of clayey soil stabilized with AASS.While the study presented some intriguing results,we have identified critical concerns regarding(i)the selection of SS as a precursor for alkali activation,(ii)technical inconsistencies associated with the compaction characteristics and microstructural analysis,and(iii)the feasibility of the proposed methodology for practical applications.Through our discussion,we seek to highlight these issues and provide constructive feedback to advance the understanding of alkali activation processes and their implications for soil stabilization.
基金supported by National Key R&D Program of China(2022YFB3506200,2022YFB3504100)National Natural Science Foundation of China(22072095,22372107,22202058)+3 种基金Excellent Youth Science Foundation of Liaoning Province(2022-YQ-20)Shenyang Science and Technology Planning Project(22-322-3-28)Liaoning Xingliao talented youth Top talent program(XLYC2203007)University Joint Education Project for China-Central and Eastern European Countries(2021097).
文摘The soot emitted during the operation of diesel engine exhaust seriously threatens the human health and environment,so treating diesel engine exhaust is critical.At present,the most effective method for eliminating soot particles is post-treatment technology.Preparation of economically viable and highly active soot combustion catalysts is a pivotal element of post-treatment technology.In this study,different single-metal oxide catalysts with fibrous structures and alkali metal-modified hollow nanotubular Mn-based oxide catalysts were synthesized using centrifugal spinning method.Activity evaluation results showed that the manganese oxide catalyst has the best catalytic activity among the prepared single-metal oxide catalysts.Further research on alkali metal modification showed that doping alkali metals is beneficial for improving the oxidation state of manganese and generating a large number of reactive oxygen species.Combined with the structural effect brought by the hollow nanotube structure,the alkali metal-modified Mn-based oxide catalysts exhibit superior catalytic performance.Among them,the Cs-modified Mn-based oxide catalyst exhibits the best catalytic performance because of its rich active oxygen species,excellent NO oxidation ability,abundant Mn^(4+)ions(M^(n4)+/Mn^(n+)=64.78%),and good redox ability.The T_(10),T_(50),T_(90),and CO_(2)selectivity of the Cs-modified Mn-based oxide catalyst were 267°C,324°C,360°C,and 97.8%,respectively.
基金financially supported by"Pioneer"and"Leading Goose"R&D Program of Zhejiang(No.2023C03130)the National Natural Science Foundation of China(No.22373029)+1 种基金Interdisciplinary Research Project of Hangzhou Normal University(No.2024JCXK02)Open Project Program of Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province(No.MTC2022-09)。
文摘An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide)(PLLA)during melt crystallization based on the selective hydrolysis of its amorphous regions.The molecular weights of the pristine PLLA(crystalline part),single stem,and single cluster were determined by gel permeation chromatography(GPC)according to their evolution during alkali hydrolysis.The maximum-folding-number(in a single cluster)and minimum-cluster-number(in one polymer chain)were obtained using these molecular weights.With the help of two numbers,the chain folding and traversing during the melt crystallization process(at 120℃)of PLLA can be described as follows.Statistically,in a single polymer chain,there are at least 2 clusters consisting of up to 6.5 stems in each of them,while the rest of the polymer chain contributes to amorphous regions.Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.
基金supported by the National Natural Science Foundation of China(No.52000172)the National Key R&D Program of China(Nos.2017YFB0304300 and 2017YFB0304303).
文摘Sulfur trioxide(SO_(3))as a condensable particle matter has a significant influence on atmospheric visibility,which easily arouses formation of haze.It is imperative to control the SO_(3)emission from the industrial flue gas.Three commonly used basic absorbents,including Ca(OH)_(2),MgO and NaHCO_(3)were selected to explore the effects of temperature,SO_(2)concentration on the SO_(3)absorption,and the reaction mechanism of SO_(3)absorption was further illustrated.The suitable reaction temperature for various absorbents were proposed,Ca(OH)_(2)at the high temperatures above 500°C,MgO at the low temperatures below 320°C,and NaHCO_(3)at the temperature range of 320–500°C.The competitive absorption between SO_(2)and SO_(3)was found that the addition of SO_(2)reduced the SO_(3)absorption on Ca(OH)_(2)and NaHCO_(3),while had no effect on MgO.The order of the absorption selectivity of SO_(3)follows MgO,NaHCO_(3)and Ca(OH)_(2)under the given conditions in this work.The absorption process of SO_(3)on NaHCO_(3)follows the shrinking core model,thus the absorption reaction continues until NaHCO_(3)was exhausted with the utilization rate of nearly 100%.The absorption process of SO_(3)on Ca(OH)_(2)and MgO follows the grain model,and the dense product layer hinders the further absorption reaction,resulting in low utilization of about 50%for Ca(OH)_(2)and MgO.The research provides a favorable support for the selection of alkaline absorbent for SO_(3)removal in application.
基金Project supported by the National Natural Science Foundation of China(51964009)。
文摘Co-associated rare earth elements(lanthanide and yttrium,REY)in coal and its by-products have been considered important potential nontraditional rare earth sources.In this study,a coal gangue sample collected from a coal processing plant in Jinsha County of Guizhou Province,southwest China,was used as the research object.The content,modes of occurrence,and extraction(acid leaching after pretreatment of selective grinding,tailings discarding,and alkali roasting)of REY from the sample were analyzed.The result shows that the content of REY(1038.26μg/g)in pyrite and quartz is low but mainly enriched in kaolinite.Under the following conditions of a filling ratio of 40%(grinding media steel ball)and grinding time of 8 min,selective grinding pretreatment is applied to achieve 176.95μg/g(yield 24.08%)and 1104.93μg/g(yield 75.92%)of REY in+2 mm and-2 mm fractions,respectively.Thus,the-2 mm coal gangue fraction is selected,used as the feed,and roasted and leached with HCl.When Na_(2)CO_(3)and NaCl are separately used as roasting activators,the REY leaching ratios are 91.41%and 68.88%,respectively,under the optimum conditions.The contents of REY in the final leachate are 1010.02 and 761.08μg/g when Na_(2)CO_(3)and NaCl are used,respectively.The two REY contents are relatively higher than the impurity ions in the leachate,which facilitates further REY separation.The mechanism study reveals that high-temperature roasting increases the pore size and the total pore area of the gangue,which promotes leachate penetration and improves reaction efficiency.In addition,roasting facilitates the reaction between the sodium salt activator and kaolinite and other aluminosilicate minerals in the coal gangue to generate soluble salts,thus releasing REY into the solution.The appropriate roasting temperature transforms the activator into a molten state.Thus,the reaction between coal gangue and activator is a solid-liquid reaction rather than a solid-solid reaction,which improves the efficiency of the chemical reaction.
基金support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Yangzhou University)(KYCX23_3508)the Yangzhou University International Academic Exchange Fund.Prof.Guoxiu Wang acknowledges the Australian Research Council(ARC)Linkage project(LP200200926).
文摘Alkali metal batteries(AMBs)have undergone substantial development in portable devices due to their high energy density and durable cycle performance.However,with the rising demand for smart wearable electronic devices,a growing focus on safety and durability becomes increasingly apparent.An effective strategy to address these increased requirements involves employing the quasi-solid gel electrolytes(QSGEs).This review focuses on the application of QSGEs in AMBs,emphasizing four types of gel electrolytes and their influence on battery performance and stability.First,self-healing gels are discussed to prolong battery life and enhance safety through self-repair mechanisms.Then,flexible gels are explored for their mechanical flexibility,making them suitable for wearable devices and flexible electronics.In addition,biomimetic gels inspired by natural designs are introduced for high-performance AMBs.Furthermore,biomass materials gels are presented,derived from natural biomaterials,offering environmental friendliness and biocompatibility.Finally,the perspectives and challenges for future developments are discussed in terms of enhancing the ionic conductivity,mechanical strength,and environmental stability of novel gel materials.The review underscores the significant contributions of these QSGEs in enhancing AMBs performance,including increased lifespan,safety,and adaptability,providing new insights and directions for future research and applications in the field.
基金supported by the National Key Research and Development Program of China(2022YFE0208300)the Natural Science Foundation of China(22078354)。
文摘The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping on Pt-based catalysts in CO_(2)-ODH reactions.The optimized 0.1 KPt/S-1 catalyst achieved a high propane conversion of 48.3%,propylene selectivity of 85.5%,and CO_(2)conversion of 19.1%at a low temperature of 500℃with the Pt loading of 0.2 wt%and K loading of 0.1 wt%respectively.Characterization techniques,including high-resolution transmission electron microscope(HR-TEM),CO-diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),X-ray absorption fine structure(XAFS),and X-ray Photoelectron Spectroscopy(XPS),revealed that the doping of K with Pt led to a strong interaction between potassium and platinum(Pt-KO_(x)cluster).This interaction resulted in a reduction of Pt particle size and a local enrichment of electron density around Pt atoms.These structural modifications improved the anchoring of Pt nanoparticles and enhanced Pt atom dispersion,thereby enhancing the activity of the catalyst and minimizing side reactions.Additionally,pyridine infrared(Py-IR)and temperature-programmed desorption(TPD)studies demonstrated that the prepared0.1 KPt/S-1 catalyst exhibited optimal acidity,which promoted C–H activation and facilitated the efficient adsorption and activation of CO_(2).These dual effects significantly lowered the activation energy for CO_(2)-ODH,enabling efficient dehydrogenation to propylene at a lower temperature of 500℃.This work highlights the critical role of alkali metal doping in modifying the electronic properties of Pt and optimizing catalyst acidity,which collectively contribute to the enhanced performance of the 0.1 KPt/S-1 catalyst.These findings offer valuable insights into the mechanistic pathway of CO_(2)-ODH and provide a foundation for the rational design of high-performance dehydrogenation catalysts.
文摘Chitin,distinguished by its nitrogen-rich acetamido and amino groups,imparts a distinctive cationic nature,enabling chitin to have indispensable features in various applications.Despite its significant promise in the textile industry,particularly for sustainable and functional fabric applications,the practical utilization of chitin fibers remains constrained by insufficient mechanical strength.The degree of deacetylation(DD),a key molecular-level structural determinant,has not been adequately addressed in previous studies despite its critical role in influencing chitin properties across multiple scales.In this study,a deacetylation-mediated design strategy was used to achieve enhanced mechanical performance coupled with multifunctional efficacy using an aqueous KOH/urea solution dissolution system.We prepared a series of deacetylated chitins with different DD values and systematically studied the effect of deacetylation on the multiple-scale structure of regenerated fibers,such as intermolecular interactions and chain orientation at the molecular level,and the aggregation behavior of chitin nanofibers within the gel-state and dried fibers at the micro/nano scale.To achieve an enhanced mechanical performance coupled with multifunctional efficacy by relying on an aqueous KOH/urea solution dissolution system.Moreover,deacetylation enhances intermolecular interactions,resulting in densified internal structures and improved fiber orientation.Concomitantly,it augmented the antimicrobial functionality of the fibers.This deacetylation-mediated design strategy provides a deeper understanding of the structure and properties of regenerated chitin and advances the utility of chitin in strong and sustainable fibers.
基金the research committee at Malek Ashtar University of Technology (MUT) for their invaluable support of this project
文摘Recent advancements have led to the synthesis of various new metal-containing explosives,particularly energetic metal-organic frameworks(EMOFs),which feature high-energy ligands within well-ordered crystalline structures.These explosives exhibit significant advantages over traditional compounds,including higher density,greater heats of detonation,improved mechanical hardness,and excellent thermal stability.To effectively evaluate their detonation performance,it is crucial to have a reliable method for predicting detonation heat,velocity,and pressure.This study leverages experimental data and outputs from the leading commercial computer code to identify suitable decomposition pathways for different metal oxides,facilitating straightforward calculations for the detonation performance of alkali metal salts,and metal coordination compounds,along with EMOFs.The new model enhances predictive reliability for detonation velocities,aligning more closely with experimental results,as evi-denced by a root mean square error(RMSE)of 0.68 km/s compared to 1.12 km/s for existing methods.Furthermore,it accommodates a broader range of compounds,including those containing Sr,Cd,and Ag,and provides predictions for EMOFs that are more consistent with computer code outputs than previous predictive models.
基金supported by the National Natural Science Foundation of China(22171136,52202138)the Natural Science Foundation of Jiangsu Province(BK20200472,BK20220079)+3 种基金the Medical Innovation and Development Project of Lanzhou University(lzuyxcx-2022-156)CAMS Innovation Fund for Medical Sciences(CIFMS,2019-I2M-5-074,2021-I2M-1-026,2021-I2M-3-001)the Frontier Technologies R&D Program of Jiangsu(Grant no.BF2024033)G.Z.acknowledges the support of the Thousand Young Talent Plan.
文摘Noteworthy challenges such as severe side reactions,interfacial instability,and dendrite growth have plagued rechargeable alkali metal batteries for a long time.Alleviating the plight necessitates innovative membranes capable of modulating ion transport and establishing stable interfaces.The exploration of implemented membranes with thermal/mechanical and electrochemical stability is crucial for achieving high-performance and safe alkali metal batteries.Crystalline covalent organic framework(COF)membranes have emerged as promising materials for next-generation energy storage systems due to their tunable porosity and exceptional physicochemical properties.This review specifically examines the critical role of COF membranes in enabling sustainable alkali metal(Li/Na/K)batteries,with a particular focus on design principles,performance advantages,and key challenges of COF membranes.The discussion emphasizes structure-property relationships specifically relevant to rechargeable battery applications,supported by recent decades of research.Impressively,this mini review further identifies three critical research frontiers:reticular chemistry-guided materials design,multifunctional composite architectures,and in-situ characterization techniques.This targeted analysis provides actionable insights for developing COF membranes that address the fundamental limitations of current alkali metal battery technologies.
基金Project(52274290)supported by the National Natural Science Foundation of ChinaProject(72088101)supported by the Basic Science Center Project for National Natural Science Foundation of China。
文摘A pre-reduction sintering process with flue gas recirculation(PSP_(fsg)-FGR)was developed to mitigate alkalis harm to the blast furnace and reduce the flue gas emission in the whole ironmaking process.The results indicated that the pre-reduction sintering process(PSP)can effectively remove 58.02%of K and 30.68%of Na from raw mixtures and improve yield and tumbler index to 74.40%and 68.69%,respectively.Moreover,PSP was conducive to reducing NO_(x) and SO_(2)emissions and simultaneously increasing CO content in flue gas.Circulating CO-containing flue gas to sintering bed effectively recycled CO and further improved K and Na removal ratio to 74.11%and 32.92%,respectively.Microstructural analysis revealed that the pre-reduced sinter mainly consisted of magnetite,wustite and a small quantity of metallic iron,and very few silicate glass phase was also formed.This process can simultaneously realize alkali metal elements removal as well as flue gas emission reduction from the integrated ironmaking process.
基金financially supported by the National Key Research and Development Program of China(No.2023YFC3707002)Hunan Provincial Innovation Foundation for Postgraduate(No.QL20220069)Postgraduate Innovative Project of Central South University(No.1053320214756).
文摘The implementation of embedded selective catalytic reduction(SCR)denitration in chain grate during iron ore pelletizing process obviates additional flue gas heating.However,the influence of gas components and alkali metal on SCR denitration requires attention.The SCR denitration behavior in the preheating section of chain grate was investigated,and the combined influence mechanisms of H_(2)O(g),SO_(2),and potassium were revealed.The results show that the presence of H_(2)O(g)and SO_(2) in the flue gas decreases the NO conversion rate of the catalyst from 96.3%to 79.5%,while potassium adsorbed on the catalyst surface further reduces the NO conversion rate to 74.1%.H_(2)O(g),SO_(2),and potassium in the flue gas form sulfate and potassium salt on the catalyst surface,blocking the pore structure,thereby decreasing the gas adsorption capacity of the catalyst.Moreover,SO_(2) and potassium engage in competitive adsorption and reaction with NH_(3) and NO at the active sites on the catalyst surface,reducing the content and activity of the catalyst effective component.Increasing the flue gas temperature can promote the decomposition of ammonium sulfate and ammonium bisulfate on the catalyst surface,but it has little effect on potassium.Additionally,potassium will exacerbate sulfur poisoning of the catalyst.Hence,the embedded SCR denitration process requires electrostatic precipitation to eliminate the adverse impacts of potassium and thermal regime optimization to raise flue gas temperature to 350℃,thereby increasing NO conversion rate exceeding 85%.
