Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,...Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.展开更多
The thermodynamic analysis of the reaction between the main phase in magnesium slag and NH_(4)Cl solutions was carried out,and the ions leaching behaviors of Ca,Mg,Fe,and Al in magnesium slag under room temperature an...The thermodynamic analysis of the reaction between the main phase in magnesium slag and NH_(4)Cl solutions was carried out,and the ions leaching behaviors of Ca,Mg,Fe,and Al in magnesium slag under room temperature and microwave conditions were compared.Meanwhile,the effects of parameters on the leaching rate of Ca and Mg were investigated under the microwave heating conditions.The experimental results show that,in 273.15-373.15 K,Ca_(2)SiO_(4),CaSiO_(3),Ca_(2)Fe_(2)O_(5),and Mg_(2)SiO_(4)might react with NH_(4)Cl solution,while MgSiO_(3),MgO,Fe_(2)O_(3),and Al_(2)O_(3)are difficult to be leached.The leaching rates of Ca and Mg are 70.29%and 24.64%,respectively,when the conditions are 300 W of microwave power,1:20 of solid-liquid ratio,400 mL of 2 mol/L NH_(4)Cl solutions,and 90 min of leaching time.In addition,in the non-isothermal stage,the leaching process of Ca is changed from chemical reaction control to diffusion control,and the leaching rate of Ca gradually increases.However,the leaching process of Mg is always controlled by chemical reaction,and the leaching rate of Mg remains unchanged after the reaction reached equilibrium.展开更多
Cr leaching is anticipated to extensively advance the activity of Cr-containing catalysts towards the oxygen evolution reaction(OER),but the underlying catalytic enhancement mechanism requires further investigation.He...Cr leaching is anticipated to extensively advance the activity of Cr-containing catalysts towards the oxygen evolution reaction(OER),but the underlying catalytic enhancement mechanism requires further investigation.Herein,NiFeCr layered double hydroxide(NiFeCr-LDH)is proposed as a proof-of-concept catalyst to elucidate the evolution of Cr species and its enhancement mechanism in OER.The incorporation of Cr(Ⅲ)ions into the lattice of NiFe-LDH is achieved through a meticulously controlled electrodeposition process,which not only promotes Cr leaching but also deepens surface reconstruction.More importantly,experimental and theoretical results demonstrate that protogenetic CrO_(4)^(2-)anions,derived from the oxidation of leached Cr ions,adsorb onto the surface NiFeCr-LDH under the anodic potential to create a CrO_(4)^(2-)-rich electrical double layer(CrO_(4)^(2-)-rich EDL)and function as co-catalyst to trigger OER.CrO_(4)^(2-)-rich EDL integrated with vacancies balances the Gibbs free energies of the reconstructed NiFeCr-LDH for oxygen-containing intermediates,resulting in an exceptionally low overpotential of 286 mV at 500 mA cm^(−2),which outperforms most state-of-the-art metallic catalysts.Additionally,the anion exchange membrane water electrolysis system assembled with NiFeCr-LDH and Pt/C demonstrates 1000-h stability at a current density of 1.0 A cm^(−2)under a voltage of 1.74 V(at 70°C),highlighting its promising potential for practical,large-scale and sustainable applications.展开更多
Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of...Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of nanoparticles. The fully oxidized Fe2O3 and Co3O4 species on Pt nanoparticle sur-faces result in the low performance of the CO complete oxidation （COOX） reaction. In contrast, un-saturated FeO and CoO surface species can be formed during exposure to the CO preferential oxida-tion （CO-PROX） reaction with an excess of H2, leading to a high O2 activation ability and enhancing the CO-PROX activity. The FeOx surface structures can be transformed between these two states by varying the reactive gas environments, exhibiting oscillating activity in these two reactions. Con-versely, the CoO surface structure formed in the H2 -rich atmosphere is stable when exposed to the COOX reaction and exhibits similar activity in these two reactions. It is hoped that this work may assist in understanding the important role of surface oxides in real reactions.展开更多
Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil wa...Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of展开更多
This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The st...This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The studied variables were the extractant concentration in the organic phase, the pH of the leached liquor and the volume ratio between organic phase and leached liquor. It was observed that D2EHPA is a better extractant than Cyanex272. Therefore, with the best experimental conditions found, both extractants reach a manganese recovery around 95% with five extraction stages conducted under the following conditions: 25?C, O/A = 2, 10% volume of extractant concentration in the organic phase, pH of the leached liquor before the mixing between 8 and 8.5, and one minute of mixing time for each extraction stage.展开更多
Layered double hydroxides(LDHs)are promising electrocatalysts for the oxygen evolution reaction(OER),yet their practical application remains limited by poor electrical conductivity and sluggish reaction kinetics.In th...Layered double hydroxides(LDHs)are promising electrocatalysts for the oxygen evolution reaction(OER),yet their practical application remains limited by poor electrical conductivity and sluggish reaction kinetics.In this work,we synthesize three high-entropy LDHs(HELDHs)featuring a hierarchical architecture of microspheres assembled from ultrathin nanosheets,via a simple hydrothermal method using a combination of low-cost,catalytically active transition metals(Fe,Co,Ni,Mn,Zn,Cu,and Cr).Among them,the FeCoNiMnZn HELDH exhibits outstanding OER performance,requiring an overpotential of only 306 mV to reach a current density of 100 mA cm^(-2).Notably,during 200 h of continuous operation,the device exhibits a stable and,in some cases,increasing current output.This exceptional activity is attributed to the formation of abundant cation vacancies,induced by Zn leaching,which enhance the intrinsic catalytic properties by optimizing the adsorption energies of key OER intermediates.Density functional theory calculations further validate that these vacancies modulate the electronic structure and lower reaction barriers,underscoring the effectiveness of cation-vacancy engineering in high-entropy systems for efficient and durable water oxidation catalysis.The optimized catalyst was further evaluated as the air cathode in a zinc-air battery,demonstrating practical electrochemical performance.展开更多
The insufficient performance of Pt and Pd benchmark catalysts remains a significant obstacle to the practical application of direct liquid fuel cells.In this study,we report a synthesis of amorphous PdSe/crystalline P...The insufficient performance of Pt and Pd benchmark catalysts remains a significant obstacle to the practical application of direct liquid fuel cells.In this study,we report a synthesis of amorphous PdSe/crystalline Pt nanoparticles(AC-PdPtSe NPs)by chemical leaching of PdPtSe NPs.AC-PdPtSe NPs display significantly enhanced activity and stability for the electrooxidation of ethylene glycol and glycerol,far surpassing that of amorphous-dominant PdPtSe NPs,commercial Pd/C,and Pt/C catalysts.Notably,the integration of crystalline and amorphous domains leverages the advantages of high electrical conductivity and a wealth of active sites,which can substantially accelerate reaction kinetics.Furthermore,detailed investigations reveal that the boundary between the Pt crystalline and PdSe amorphous phases induces a 3%surface tensile strain.The formation of amorphous-crystalline heterointerfaces optimizes the d-band states,thereby strengthening the adsorption and activation of ethylene glycol and glycerol.This study highlights the advance in phase engineering toward the development of highly active noble-metal nanostructures.展开更多
In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics...In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.展开更多
Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which ...Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which relies on lixiviants prepared using volatilized sulfur obtained from roasting,has not been fully elucidated.This study employs the response surface methodology to optimize processing parameters,resulting in an increased gold extraction rate of 96.18%.Analytical factorization and the Tafel curve indicate that CuSO_(4) and NH_(3)·H_(2)O significantly influence the self-leaching process.Furthermore,X-ray photoelectron spectroscopy(XPS)analysis reveals that S^(2−),S_(2)^(2−),polysulfides(S_(n)^(2−)),and thiosulfate(S_(2)O_(3)^(2−))are involved in the gold leaching reaction,with S^(2−),S_(2)^(2−),and S_(n)^(2−) serving as primary ligands for gold complexation.The role of S_(2)O_(3)^(2−) in the early stages of the gold-leaching reaction is also noteworthy.The copper–ammonia complex catalyzes the self-leaching gold reaction;however,an improper addition ratio can lead to copper-sulfur compound precipitates,reducing the extraction rate.展开更多
The microstructural variations of hardened cement-fly ash pastes leached by soft water were investigated by MIP, XRD, TG and SEM. The results show that the mass of hardened cement-fly ash paste reduces and its microst...The microstructural variations of hardened cement-fly ash pastes leached by soft water were investigated by MIP, XRD, TG and SEM. The results show that the mass of hardened cement-fly ash paste reduces and its microstructure deteriorates partly after leaching of soft water. At the leaching duration of 180 days, the hardened paste containing fly ash deteriorated a little more serious than the plain cement paste, but the incorporation of fly ash in a proper ratio was helpful to defer the trend of deterioration of the hardened paste microstructure. The microstructural stability of hardened cement-fly ash paste wasn’t damaged severely during the 180 days leaching duration.展开更多
Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods ...Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods In this study,we conducted laboratory experiments to investigate the processes of DOM leaching from three common marsh plants(Phragmites australis,Suaeda salsa and Aeluropus littoralis)collected from the Yellow River Delta(YRD)salt marsh in October 2016.The YRD is one of the largest and most well-protected coastal ecosystems on the east coast of China.Important Findings We found that the plant leaves released DOM at much higher concentrations than the plant roots or stems,as measured by the dissolved organic carbon(DOC)and dissolved nitrogen(DN).On average,15%of the biomass C and 30%of the biomass N were released from the plant leaves as DOC and DN during the 27-day incubation period.The DOM released from the plants was very labile,and 92.4%-98.1%of the DOC and 88.0%-94.6%of the DN released from the plants were consumed by bacteria during the 27-day incubation period.The fluorescence characteristics of the plant-released DOM indicated that chromophoric dissolved organic matter was a major fraction of the DOM and that protein-like components were the primary organic fractions released from the plants.Bacterial degradation altered both the fluorescence properties and the chemical composition of the DOM.The results of the laboratory experiments were well supported by the field investigation,which indicated that a large amount of DOM was outwelled from the YRD salt marshes in late autumn.Our study suggests that the DOM released from the biomass of salt marsh plants provides an important source of both DOC and DN for marsh and coastal waters.The highly labile DOC and DN provide essential food sources to support microbial communities in the YRD salt marsh and adjacent coastal waters.展开更多
为维护网络运行安全,保证网络信息安全存储,提出基于多源数据挖掘的网络安全态势评估系统。首先建立以应用层、控制层、数据转发层为核心的3层网络安全态势系统架构,为保证应用层与网络设备之间信息有效传输,利用OSGi(Open Service Gate...为维护网络运行安全,保证网络信息安全存储,提出基于多源数据挖掘的网络安全态势评估系统。首先建立以应用层、控制层、数据转发层为核心的3层网络安全态势系统架构,为保证应用层与网络设备之间信息有效传输,利用OSGi(Open Service Gateway Initiative)设计模式对控制层的ONOS(Open Network Operating System)控制器实施5层平行建构,以保障网络安全态势的决策响应。利用流量探测模块内多探测器的部署,实现网络多源数据的深度挖掘;引入LEACH(Low Energy Adaptive Clustering Hierarchy)算法,在网络簇首实现多源数据融合。通过安全态势评估模块对网络入侵因子威胁等级进行分析后,结合权系数理论对网络态势威胁因子进行威胁度赋值,并结合网络层次划分法对运行网络服务层、主机层、网络层安全态势实施分层评估。实验表明,所提方法对网络数据运行状态分析能力较高,面对多类型网络威胁因子的攻击行为能做到精准识别,为网络安全运行提供重要保障。展开更多
The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with t...The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with the advantage of being environmental-friendly.As one of the organic acids produced by biological metabolism,citric acid was used to leach REEs and explore the performance and process.The results demonstrate that citric acid exhibits higher leaching efficiency(96.00%)for REEs at a relatively low concentration of 0.01 mol/L compared with(NH_(4))_(2)SO_(4)(84.29%,0.1 mol/L)and MgSO_(4)(83.99%,0.1 mol/L).Citric acid shows a preference for leaching heavy rare earth elements,with 99%leaching efficiency in IAREO,which shows higher capacity than(NH_(4))_(2)SO_(4)and MgSO_(4)(as inorganic leaching agents).Kinetic analysis indicates that the leaching process of REEs with citric acid is controlled by both the internal diffusion kinetics and chemical reaction kinetics,which is different from inorganic leaching agents.Visual Minteq calculations confirm that RE-Citrate is the main constituent of the extract solution in the leaching process of the IAREO,thereby enhancing the leaching efficiency of REEs from the IAREO.It suggests that citric acid may be used as a promising organic leaching agent for the environmentalfriendly extraction of REEs from IAREO.展开更多
文摘Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.
基金Funded by the National Key Research and Development Program of China(No.2023YFC2908002)。
文摘The thermodynamic analysis of the reaction between the main phase in magnesium slag and NH_(4)Cl solutions was carried out,and the ions leaching behaviors of Ca,Mg,Fe,and Al in magnesium slag under room temperature and microwave conditions were compared.Meanwhile,the effects of parameters on the leaching rate of Ca and Mg were investigated under the microwave heating conditions.The experimental results show that,in 273.15-373.15 K,Ca_(2)SiO_(4),CaSiO_(3),Ca_(2)Fe_(2)O_(5),and Mg_(2)SiO_(4)might react with NH_(4)Cl solution,while MgSiO_(3),MgO,Fe_(2)O_(3),and Al_(2)O_(3)are difficult to be leached.The leaching rates of Ca and Mg are 70.29%and 24.64%,respectively,when the conditions are 300 W of microwave power,1:20 of solid-liquid ratio,400 mL of 2 mol/L NH_(4)Cl solutions,and 90 min of leaching time.In addition,in the non-isothermal stage,the leaching process of Ca is changed from chemical reaction control to diffusion control,and the leaching rate of Ca gradually increases.However,the leaching process of Mg is always controlled by chemical reaction,and the leaching rate of Mg remains unchanged after the reaction reached equilibrium.
基金the support of this research by the National Key Research and Development Program of China(2024YFB4106400)the National Natural Science Foundation of China(22179035)the Science Fund for Distinguished Young Scholars of Heilongjiang Province(JQ2022B001)。
文摘Cr leaching is anticipated to extensively advance the activity of Cr-containing catalysts towards the oxygen evolution reaction(OER),but the underlying catalytic enhancement mechanism requires further investigation.Herein,NiFeCr layered double hydroxide(NiFeCr-LDH)is proposed as a proof-of-concept catalyst to elucidate the evolution of Cr species and its enhancement mechanism in OER.The incorporation of Cr(Ⅲ)ions into the lattice of NiFe-LDH is achieved through a meticulously controlled electrodeposition process,which not only promotes Cr leaching but also deepens surface reconstruction.More importantly,experimental and theoretical results demonstrate that protogenetic CrO_(4)^(2-)anions,derived from the oxidation of leached Cr ions,adsorb onto the surface NiFeCr-LDH under the anodic potential to create a CrO_(4)^(2-)-rich electrical double layer(CrO_(4)^(2-)-rich EDL)and function as co-catalyst to trigger OER.CrO_(4)^(2-)-rich EDL integrated with vacancies balances the Gibbs free energies of the reconstructed NiFeCr-LDH for oxygen-containing intermediates,resulting in an exceptionally low overpotential of 286 mV at 500 mA cm^(−2),which outperforms most state-of-the-art metallic catalysts.Additionally,the anion exchange membrane water electrolysis system assembled with NiFeCr-LDH and Pt/C demonstrates 1000-h stability at a current density of 1.0 A cm^(−2)under a voltage of 1.74 V(at 70°C),highlighting its promising potential for practical,large-scale and sustainable applications.
基金supported by the National Natural Science Foundation of China(21403004,21403003)~~
文摘Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of nanoparticles. The fully oxidized Fe2O3 and Co3O4 species on Pt nanoparticle sur-faces result in the low performance of the CO complete oxidation （COOX） reaction. In contrast, un-saturated FeO and CoO surface species can be formed during exposure to the CO preferential oxida-tion （CO-PROX） reaction with an excess of H2, leading to a high O2 activation ability and enhancing the CO-PROX activity. The FeOx surface structures can be transformed between these two states by varying the reactive gas environments, exhibiting oscillating activity in these two reactions. Con-versely, the CoO surface structure formed in the H2 -rich atmosphere is stable when exposed to the COOX reaction and exhibits similar activity in these two reactions. It is hoped that this work may assist in understanding the important role of surface oxides in real reactions.
文摘Experiment was conducted for five successiveyears under large undisturbed monolith lysime-ters(2m×2m in square,l m in depth).Thesoil was silty clay loam texture and had a con-tent of total N 1.55 g/kg.The soil was flood-ed with penetration rate controlled at approxi-mate 3 mm per day in duration of double-riceseason and laid fallow and natural in winterand spring.Results showed that nitrate was the mainform of nitrogen in percolates.The change of
文摘This paper compares the efficiency of D2EHPA and Cyanex 272 to extract the divalent manganese cation from an actual leaching solution obtained by reductive leaching of a low-grade pyrolusite ore, using SO2 gas. The studied variables were the extractant concentration in the organic phase, the pH of the leached liquor and the volume ratio between organic phase and leached liquor. It was observed that D2EHPA is a better extractant than Cyanex272. Therefore, with the best experimental conditions found, both extractants reach a manganese recovery around 95% with five extraction stages conducted under the following conditions: 25?C, O/A = 2, 10% volume of extractant concentration in the organic phase, pH of the leached liquor before the mixing between 8 and 8.5, and one minute of mixing time for each extraction stage.
基金supported by the National Natural Science Foundation of China(NSFC)(22302151,52502312)Natural Science Foundation of Hubei Province(2024AFB755,2024AFB267)+1 种基金Key Project of Hubei Provincial Department of Education Scientific Research Plan(F2023007)Wuhan Institute of Technology Graduate Education Innovation Fund(CX2024285)。
文摘Layered double hydroxides(LDHs)are promising electrocatalysts for the oxygen evolution reaction(OER),yet their practical application remains limited by poor electrical conductivity and sluggish reaction kinetics.In this work,we synthesize three high-entropy LDHs(HELDHs)featuring a hierarchical architecture of microspheres assembled from ultrathin nanosheets,via a simple hydrothermal method using a combination of low-cost,catalytically active transition metals(Fe,Co,Ni,Mn,Zn,Cu,and Cr).Among them,the FeCoNiMnZn HELDH exhibits outstanding OER performance,requiring an overpotential of only 306 mV to reach a current density of 100 mA cm^(-2).Notably,during 200 h of continuous operation,the device exhibits a stable and,in some cases,increasing current output.This exceptional activity is attributed to the formation of abundant cation vacancies,induced by Zn leaching,which enhance the intrinsic catalytic properties by optimizing the adsorption energies of key OER intermediates.Density functional theory calculations further validate that these vacancies modulate the electronic structure and lower reaction barriers,underscoring the effectiveness of cation-vacancy engineering in high-entropy systems for efficient and durable water oxidation catalysis.The optimized catalyst was further evaluated as the air cathode in a zinc-air battery,demonstrating practical electrochemical performance.
基金supported by the National Natural Science Foundation of China(Nos.52274304,52073199).
文摘The insufficient performance of Pt and Pd benchmark catalysts remains a significant obstacle to the practical application of direct liquid fuel cells.In this study,we report a synthesis of amorphous PdSe/crystalline Pt nanoparticles(AC-PdPtSe NPs)by chemical leaching of PdPtSe NPs.AC-PdPtSe NPs display significantly enhanced activity and stability for the electrooxidation of ethylene glycol and glycerol,far surpassing that of amorphous-dominant PdPtSe NPs,commercial Pd/C,and Pt/C catalysts.Notably,the integration of crystalline and amorphous domains leverages the advantages of high electrical conductivity and a wealth of active sites,which can substantially accelerate reaction kinetics.Furthermore,detailed investigations reveal that the boundary between the Pt crystalline and PdSe amorphous phases induces a 3%surface tensile strain.The formation of amorphous-crystalline heterointerfaces optimizes the d-band states,thereby strengthening the adsorption and activation of ethylene glycol and glycerol.This study highlights the advance in phase engineering toward the development of highly active noble-metal nanostructures.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.
基金supported by the National Natural Science Foundation of China(No.51974016).
文摘Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which relies on lixiviants prepared using volatilized sulfur obtained from roasting,has not been fully elucidated.This study employs the response surface methodology to optimize processing parameters,resulting in an increased gold extraction rate of 96.18%.Analytical factorization and the Tafel curve indicate that CuSO_(4) and NH_(3)·H_(2)O significantly influence the self-leaching process.Furthermore,X-ray photoelectron spectroscopy(XPS)analysis reveals that S^(2−),S_(2)^(2−),polysulfides(S_(n)^(2−)),and thiosulfate(S_(2)O_(3)^(2−))are involved in the gold leaching reaction,with S^(2−),S_(2)^(2−),and S_(n)^(2−) serving as primary ligands for gold complexation.The role of S_(2)O_(3)^(2−) in the early stages of the gold-leaching reaction is also noteworthy.The copper–ammonia complex catalyzes the self-leaching gold reaction;however,an improper addition ratio can lead to copper-sulfur compound precipitates,reducing the extraction rate.
基金supported by the National Basic Research Program ("973" Project) (Grant No 2009CB623106)the Key Project of Beijing Natu-ral Science Foundation (Grant No 8100001)
文摘The microstructural variations of hardened cement-fly ash pastes leached by soft water were investigated by MIP, XRD, TG and SEM. The results show that the mass of hardened cement-fly ash paste reduces and its microstructure deteriorates partly after leaching of soft water. At the leaching duration of 180 days, the hardened paste containing fly ash deteriorated a little more serious than the plain cement paste, but the incorporation of fly ash in a proper ratio was helpful to defer the trend of deterioration of the hardened paste microstructure. The microstructural stability of hardened cement-fly ash paste wasn’t damaged severely during the 180 days leaching duration.
基金supported by the National Natural Science Foundation of China(grants#41776082 and 41476057)Funds of Jiangsu Key Laboratory of Marine Biotechnology of Jiangsu Ocean University(HS2019005)the Funds of Jiangsu Key Laboratory of Marine Bioresources and Environment(SH20191205)and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Aims Salt marsh vegetation is an important contributor of dissolved organic matter(DOM)to coastal waters.The dynamics of DOM leaching from different marsh plants,however,have not been well studied or compared.Methods In this study,we conducted laboratory experiments to investigate the processes of DOM leaching from three common marsh plants(Phragmites australis,Suaeda salsa and Aeluropus littoralis)collected from the Yellow River Delta(YRD)salt marsh in October 2016.The YRD is one of the largest and most well-protected coastal ecosystems on the east coast of China.Important Findings We found that the plant leaves released DOM at much higher concentrations than the plant roots or stems,as measured by the dissolved organic carbon(DOC)and dissolved nitrogen(DN).On average,15%of the biomass C and 30%of the biomass N were released from the plant leaves as DOC and DN during the 27-day incubation period.The DOM released from the plants was very labile,and 92.4%-98.1%of the DOC and 88.0%-94.6%of the DN released from the plants were consumed by bacteria during the 27-day incubation period.The fluorescence characteristics of the plant-released DOM indicated that chromophoric dissolved organic matter was a major fraction of the DOM and that protein-like components were the primary organic fractions released from the plants.Bacterial degradation altered both the fluorescence properties and the chemical composition of the DOM.The results of the laboratory experiments were well supported by the field investigation,which indicated that a large amount of DOM was outwelled from the YRD salt marshes in late autumn.Our study suggests that the DOM released from the biomass of salt marsh plants provides an important source of both DOC and DN for marsh and coastal waters.The highly labile DOC and DN provide essential food sources to support microbial communities in the YRD salt marsh and adjacent coastal waters.
基金Project supported by the Thousand Talents Program of Jiangxi Province,China(JXSQ2023201003)National Natural Science Foundation of China(42107254)+4 种基金Science and Technology Major Program of Ordos City(2022EEDSKJZDZX014-2)Technological Innovation Guidance Program of Jiangxi Province(20212BDH81029)Rare Earth Industry Fund(IAGM2020DB06)Selfdeployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055A01)the Key Research Program of the Chinese Academy of Sciences(ZDRW-CN-2021-3-3)。
文摘The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with the advantage of being environmental-friendly.As one of the organic acids produced by biological metabolism,citric acid was used to leach REEs and explore the performance and process.The results demonstrate that citric acid exhibits higher leaching efficiency(96.00%)for REEs at a relatively low concentration of 0.01 mol/L compared with(NH_(4))_(2)SO_(4)(84.29%,0.1 mol/L)and MgSO_(4)(83.99%,0.1 mol/L).Citric acid shows a preference for leaching heavy rare earth elements,with 99%leaching efficiency in IAREO,which shows higher capacity than(NH_(4))_(2)SO_(4)and MgSO_(4)(as inorganic leaching agents).Kinetic analysis indicates that the leaching process of REEs with citric acid is controlled by both the internal diffusion kinetics and chemical reaction kinetics,which is different from inorganic leaching agents.Visual Minteq calculations confirm that RE-Citrate is the main constituent of the extract solution in the leaching process of the IAREO,thereby enhancing the leaching efficiency of REEs from the IAREO.It suggests that citric acid may be used as a promising organic leaching agent for the environmentalfriendly extraction of REEs from IAREO.
