A novel method for scandium recovery is proposed through high-surface area silanol-rich silica sorbents which were prepared with calcium silicate hydrate(C-S-H) as raw material.Two types of silanol-rich silica particl...A novel method for scandium recovery is proposed through high-surface area silanol-rich silica sorbents which were prepared with calcium silicate hydrate(C-S-H) as raw material.Two types of silanol-rich silica particles,i.e.,LAC-S(silica derived from acid leaching of amorphous C-S-H) and LLC-S(silica derived from acid leaching of low-crystallinity C-S-H) are obtained after calcium ions are removed from both amorphous and low-crystallinity forms of C-S-H through a facile acid leaching process(3 mol/L,25℃,24 h).(29)^Si NMR spectroscopy reveals that the proportion of silicon atoms carrying silanol groups increases from less than 43% to over 80% when silica particles are transferred from a dry state to an aqueous solution.Batch adsorption experiments were conducted to evaluate the sorption performance and selectivity of these silica sorbents toward Sc(Ⅲ).The scandium sorption capacities of LAC-S and LLC-S at an equilibrium pH of 4.2 are 174.45 and 129.57 mg/g,respectively.The separation factors(SFSc/Ln) of both silica particles exceed 1000 in the initial pH range of 3.5-5.The loaded scandium ions are recovered with 3 mol/L hydrochloric acid and the sorbents exhibit good reusability.This strategy provides an efficient and green method for recovering scandium from aqueous solutions.展开更多
Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involv...Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.展开更多
Additive manufacturing(AM),also called three-dimensional(3D)printing,has been developed to obtain energetic materials within the past decade.3D printing represents a family of flexible manufacturing techniques that en...Additive manufacturing(AM),also called three-dimensional(3D)printing,has been developed to obtain energetic materials within the past decade.3D printing represents a family of flexible manufacturing techniques that enable fast and accurate fabrication of structures with complex 3D features and a broad range of sizes,from submicrometer to several meters.Various methods have already been explored,including templating,melting extrusion,inkjet printing and electrospray methods.It was demonstrated that the structure achieved by AM could be used to manipulate the reactivity of energetic or reactive materials by changing the flow of gases and entrained particles via architecture.By employing different AM techniques,energetic materials with controllable nanostructures and uniformly dispersed ingredients can be prepared.It is exciting to tailor the energy release without defaulting to change the formulation of the conventional method.The combustion and mechanical properties of conventional energetic materials can be retained at the same time.In this review,the preparation and characterization of AM energetic materials that have been developed in the last decade are summarized.Various AM techniques used in the fabrication of energetic materials are compared and discussed.In particular,formulations of energetic materials applied in AM,metallic fuels,binders and energetic fillers and their advantages in terms of combustion efficiency and other properties are proposed.展开更多
To effectively separate and recover Co(Ⅱ) from the leachate of spent lithium-ion battery cathodes,we investigated solvent extraction with quaternary ammonium salt N263 in the sodium nitrite system.NO_(2)^(-)combines ...To effectively separate and recover Co(Ⅱ) from the leachate of spent lithium-ion battery cathodes,we investigated solvent extraction with quaternary ammonium salt N263 in the sodium nitrite system.NO_(2)^(-)combines with Co(Ⅱ) to form an anion [Co(NO_(2))_(3)]^(-),and it is then extracted by N263.The extraction of Co(Ⅱ) is related to the concentration of NO_(2)^(-).The extraction efficiency of Co(Ⅱ) reaches the maximum of99.16%,while the extraction efficiencies of Ni(Ⅱ),Mn(Ⅱ),and Li(Ⅰ) are 9.27%-9.80% under the following conditions:30vol% of N263 and15vol% of iso-propyl alcohol in sulfonated kerosene,the volume ratio of the aqueous-to-organic phase is 2:1,the extraction time is 30 min,and1 M sodium nitrite in 0.1 MHNO_(3).The theoretical stages require for the Co(Ⅱ) extraction are performed in the McCabe–Thiele diagram,and the extraction efficiency of Co(Ⅱ) reaches more than 99.00% after three-stage counter-current extraction with Co(Ⅱ) concentration of 2544mg/L.When the HCl concentration is 1.5 M,the volume ratio of the aqueous-to-organic phase is 1:1,the back-extraction efficiency of Co(Ⅱ)achieves 91.41%.After five extraction and back-extraction cycles,the Co(Ⅱ) extraction efficiency can still reach 93.89%.The Co(Ⅱ) extraction efficiency in the actual leaching solution reaches 100%.展开更多
With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen...With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.展开更多
In practice,some multi-objective optimization problems exhibit expensive calculation characteristic,called expensive multi-objective optimization problems(EMOPs).Most of the existing expensive multi-objective evolutio...In practice,some multi-objective optimization problems exhibit expensive calculation characteristic,called expensive multi-objective optimization problems(EMOPs).Most of the existing expensive multi-objective evolutionary algorithms do not consider the discontinuity of Pareto front(PF),their performance is not ideal when solving EMOPs with discontinuous PF.In view of this,this paper proposes a surrogate-assisted multi-objective evolutionary algorithm with discontinuity-inducing variables(VD-SAMOEA).First,a method combining density clustering and random sampling is developed to identify variables that significantly impact the discontinuity of PF.And then,based on the identified discontinuity-inducing variables,a local exploitation strategy with varying search intervals is presented to improve the algorithm’s search performance for the sparse PF segments.Further,a local surrogate model construction method based on geodesic flow kernel multi-source transfer learning is proposed to improve the accuracy of the local surrogate model on the exploited region.Moreover,a convergence-indicator-guided hybrid global search strategy is proposed to balance the diversity and convergence of the population.Finally,experimental results on 20 test functions and the carbon fiber spinning problem indicate that,compared to 11 typical algorithms,the proposed algorithm can obtain high-quality Pareto optimal solutions with a lower computational cost.展开更多
of main observation and conclusion In order to explore the effects of fluoro substituents on the energy and safety of energetic compounds,a series of fluorodinitrobenzenes including l,3-difluoro-2,4-dinitrobenzene(1),...of main observation and conclusion In order to explore the effects of fluoro substituents on the energy and safety of energetic compounds,a series of fluorodinitrobenzenes including l,3-difluoro-2,4-dinitrobenzene(1),1,5-difluoro-2,4-dinitrobenzene(2),1,2,3-trifluoro-4,6-dinitrobenzne(3)and 1,3,5-trifluoro-2,4-dinitrobenzene(4)were prepared.All the compounds were fully characterized.The structures of 2 and 3 were further confirmed by single crystal X-ray diffraction analysis.The results show that these compounds exhibit comparable detonation properties(D=6703-6978 m s^-1,and p=21.3-23.76Pa)to those of 2,4,6-trinitrotoluene(TNT)due to the significantly increased density of fluorine introduced.Low sensitivity(IS>40 J,and FS>360 N)of these compounds along with different melting points make them potential candidates for different allocation.Among them,1 and 4 with the melting point of 42.5℃and 55.2℃,respectively,show promise for application in the field of energetic plasticizer.Compounds 2 and 3 are potential low sensitive melt-cast carrier due to their similar melting point and superior detonation performance to that of TNT.展开更多
基金Project supported by the National Natural Science Foundation of China (52064002)Guangxi Science and Technology Major Project(AA23073018)。
文摘A novel method for scandium recovery is proposed through high-surface area silanol-rich silica sorbents which were prepared with calcium silicate hydrate(C-S-H) as raw material.Two types of silanol-rich silica particles,i.e.,LAC-S(silica derived from acid leaching of amorphous C-S-H) and LLC-S(silica derived from acid leaching of low-crystallinity C-S-H) are obtained after calcium ions are removed from both amorphous and low-crystallinity forms of C-S-H through a facile acid leaching process(3 mol/L,25℃,24 h).(29)^Si NMR spectroscopy reveals that the proportion of silicon atoms carrying silanol groups increases from less than 43% to over 80% when silica particles are transferred from a dry state to an aqueous solution.Batch adsorption experiments were conducted to evaluate the sorption performance and selectivity of these silica sorbents toward Sc(Ⅲ).The scandium sorption capacities of LAC-S and LLC-S at an equilibrium pH of 4.2 are 174.45 and 129.57 mg/g,respectively.The separation factors(SFSc/Ln) of both silica particles exceed 1000 in the initial pH range of 3.5-5.The loaded scandium ions are recovered with 3 mol/L hydrochloric acid and the sorbents exhibit good reusability.This strategy provides an efficient and green method for recovering scandium from aqueous solutions.
基金supported by the National Natural Science Foundation of China(No.22375021,22235003,22261132516&22205021)the BIT Research and Innovation 265 Promoting Project(Grant No.2023YCXZ017)。
文摘Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers.In this work,an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance.Utilizing this dual strategy,3,5-bis(trinitromethyl)-1,2,4-oxadiazole(3)was synthesized,resulting in the formation of two distinct crystal morphologies(needle and sheet)corresponding to two crystal forms(3-a and3-b).Encouragingly,while maintaining ultra-high oxygen balance(21.73%),3 achieves impressive densities(1.97-1.98 g/cm^(3)).To our knowledge,the density of 1.98 g/cm^(3)for 3-a sets a new record among that of nitrogen-rich monocyclic compounds.Notably,practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3,increasing the impact sensitivity and friction sensitivity from 1 J to 80 N(3-a)to 10 J and 240 N(3-b),respectively.Additionally,the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability.This work provides an efficient strategy to enhance performance of trinitromethyl derivatives,broadening the path and expanding the toolbox for energetic materials.
基金the National Natural Science Foundation of China(Nos.21875020 and 22075024)。
文摘Additive manufacturing(AM),also called three-dimensional(3D)printing,has been developed to obtain energetic materials within the past decade.3D printing represents a family of flexible manufacturing techniques that enable fast and accurate fabrication of structures with complex 3D features and a broad range of sizes,from submicrometer to several meters.Various methods have already been explored,including templating,melting extrusion,inkjet printing and electrospray methods.It was demonstrated that the structure achieved by AM could be used to manipulate the reactivity of energetic or reactive materials by changing the flow of gases and entrained particles via architecture.By employing different AM techniques,energetic materials with controllable nanostructures and uniformly dispersed ingredients can be prepared.It is exciting to tailor the energy release without defaulting to change the formulation of the conventional method.The combustion and mechanical properties of conventional energetic materials can be retained at the same time.In this review,the preparation and characterization of AM energetic materials that have been developed in the last decade are summarized.Various AM techniques used in the fabrication of energetic materials are compared and discussed.In particular,formulations of energetic materials applied in AM,metallic fuels,binders and energetic fillers and their advantages in terms of combustion efficiency and other properties are proposed.
基金financially supported by the National Natural Science Foundation of China(No.51804084)the Natural Science Foundation of Guangxi Province,China(No.2021GXNSFAA220096)the Science and Technology Major Project of Guangxi Province,China(No.AA17204100)。
文摘To effectively separate and recover Co(Ⅱ) from the leachate of spent lithium-ion battery cathodes,we investigated solvent extraction with quaternary ammonium salt N263 in the sodium nitrite system.NO_(2)^(-)combines with Co(Ⅱ) to form an anion [Co(NO_(2))_(3)]^(-),and it is then extracted by N263.The extraction of Co(Ⅱ) is related to the concentration of NO_(2)^(-).The extraction efficiency of Co(Ⅱ) reaches the maximum of99.16%,while the extraction efficiencies of Ni(Ⅱ),Mn(Ⅱ),and Li(Ⅰ) are 9.27%-9.80% under the following conditions:30vol% of N263 and15vol% of iso-propyl alcohol in sulfonated kerosene,the volume ratio of the aqueous-to-organic phase is 2:1,the extraction time is 30 min,and1 M sodium nitrite in 0.1 MHNO_(3).The theoretical stages require for the Co(Ⅱ) extraction are performed in the McCabe–Thiele diagram,and the extraction efficiency of Co(Ⅱ) reaches more than 99.00% after three-stage counter-current extraction with Co(Ⅱ) concentration of 2544mg/L.When the HCl concentration is 1.5 M,the volume ratio of the aqueous-to-organic phase is 1:1,the back-extraction efficiency of Co(Ⅱ)achieves 91.41%.After five extraction and back-extraction cycles,the Co(Ⅱ) extraction efficiency can still reach 93.89%.The Co(Ⅱ) extraction efficiency in the actual leaching solution reaches 100%.
基金supported by the National Natural Science Foundation of China (No.52364022)the Natural Science Foundation of Guangxi Province,China (Nos.2023JJA160192 and 2021GXNSFAA220096)+1 种基金the Guangxi Science and Technology Major Project,China (No.AA23073018)the Guangxi Chongzuo Science and Technology Plan,China (No.2023ZY00503).
文摘With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.
基金supported supported by the Science and Technology Research Project of Henan Province(No.242102211095)the National Natural Science Foundation of China(Nos.62273348 and 62203446)the Young Talent Cultivation Project of North Minzu University(No.2024QNPY04).
文摘In practice,some multi-objective optimization problems exhibit expensive calculation characteristic,called expensive multi-objective optimization problems(EMOPs).Most of the existing expensive multi-objective evolutionary algorithms do not consider the discontinuity of Pareto front(PF),their performance is not ideal when solving EMOPs with discontinuous PF.In view of this,this paper proposes a surrogate-assisted multi-objective evolutionary algorithm with discontinuity-inducing variables(VD-SAMOEA).First,a method combining density clustering and random sampling is developed to identify variables that significantly impact the discontinuity of PF.And then,based on the identified discontinuity-inducing variables,a local exploitation strategy with varying search intervals is presented to improve the algorithm’s search performance for the sparse PF segments.Further,a local surrogate model construction method based on geodesic flow kernel multi-source transfer learning is proposed to improve the accuracy of the local surrogate model on the exploited region.Moreover,a convergence-indicator-guided hybrid global search strategy is proposed to balance the diversity and convergence of the population.Finally,experimental results on 20 test functions and the carbon fiber spinning problem indicate that,compared to 11 typical algorithms,the proposed algorithm can obtain high-quality Pareto optimal solutions with a lower computational cost.
基金Authors are grateful for the support of the National Natural Science Foundation of China(Grant Nos.21702017,21875020)SKLST(BIT)QNKT18-03.
文摘of main observation and conclusion In order to explore the effects of fluoro substituents on the energy and safety of energetic compounds,a series of fluorodinitrobenzenes including l,3-difluoro-2,4-dinitrobenzene(1),1,5-difluoro-2,4-dinitrobenzene(2),1,2,3-trifluoro-4,6-dinitrobenzne(3)and 1,3,5-trifluoro-2,4-dinitrobenzene(4)were prepared.All the compounds were fully characterized.The structures of 2 and 3 were further confirmed by single crystal X-ray diffraction analysis.The results show that these compounds exhibit comparable detonation properties(D=6703-6978 m s^-1,and p=21.3-23.76Pa)to those of 2,4,6-trinitrotoluene(TNT)due to the significantly increased density of fluorine introduced.Low sensitivity(IS>40 J,and FS>360 N)of these compounds along with different melting points make them potential candidates for different allocation.Among them,1 and 4 with the melting point of 42.5℃and 55.2℃,respectively,show promise for application in the field of energetic plasticizer.Compounds 2 and 3 are potential low sensitive melt-cast carrier due to their similar melting point and superior detonation performance to that of TNT.
