Cadmium(Cd)contamination in soils poses substantial environmental and health risks globally,with manganese(Mn)playing a crucial role in regulating Cd mobility through soil adsorption processes and shared crop uptake p...Cadmium(Cd)contamination in soils poses substantial environmental and health risks globally,with manganese(Mn)playing a crucial role in regulating Cd mobility through soil adsorption processes and shared crop uptake pathways.While the importance of understanding Cd-Mn dynamics in soils is widely recognized,quantitative assessments of their correlated desorption processes remain limited.This study employed diffusive gradients in thin-films(DGT)technique combined with DGT-induced fluxes in soils(DIFS)modeling to investigate Cd and Mn availability and desorption dynamics in karst soils from Guangxi,southwestern China.The soil solution concentrations ranged from 0.23–1.82μg/L for Cd and 1.29–8.41 mg/L for Mn.DGT measurements demonstrated nonlinear accumulation patterns for both metals over 48 h duration.DIFS modeling yielded distribution coefficients(Kdl)ranging from 2.50 to 807 mL/g and response time(Tc)between 1.27 and 425 s for both metals.Solid phase resupply was limited by desorption rates of 5.38–229×10^(−5)/s,providing unprecedented insight into the kinetics of metal release in these soils.Analysis of metal desorption rate ratios(k−1-Mn/k−1-Cd)indicated that soil organic matter content,clay content,pH,and metal contents collectively control Cd and Mn desorption kinetics,leading to distinct desorption patterns across soils with varying physicochemical properties.These findings demonstrate rapid equilibrium reestablishment and desorption-limited resupply characteristics of Cd and Mn in karst soils,advancing understanding of correlative metal behaviors in these unique geological settings.展开更多
Flotation is the most common method to recover valuable minerals by selective adsorption of collectors on target mineral surfaces.However,in subsequent hydrometallurgy of mineral flotation concentrates,the adsorbed co...Flotation is the most common method to recover valuable minerals by selective adsorption of collectors on target mineral surfaces.However,in subsequent hydrometallurgy of mineral flotation concentrates,the adsorbed collectors must be desorbed since it can adversely affect the efficiency of metallurgical process and produce wastewater.ZL,as a fatty acid mixture,is a typical industrially used collector for scheelite flotation in China.Sodium oleate(NaOL)has similar fatty acid group as ZL.In this study,the desorption behavior of NaOL/ZL from scheelite surface by a physical method of stirring at a low temperature was investigated.NaOL desorption tests of single mineral showed that a desorption rate of 77.75% for NaOL from scheelite surface into pulp was achieved in a stirring speed of2500 r/min at 5℃in a neutral environment.Under the above desorption condition,in the pulp containing desorbed collector by adding extra 30% normal NaOL dosage,the scheelite recovery reached about 95% in the single mineral flotation test.Desorption and reuse of ZL collector for the flotation of real scheelite ore showed only a 75%normal dosage of ZL could produce a qualified rough concentrate.The atomic force microscope(AFM)tests showed that after desorption treatment of low temperature and strong stirring,the dense strip-like structure of NaOL on the scheelite surface was destroyed to be speck-like.Molecular dynamics simulations(MDS)demonstrated that the adsorption energy between NaOL and scheelite surface was more negative at 25℃(-13.39 kcal/mol)than at 5℃(-11.50 kcal/mol)in a neutral pH,indicating that a low temperature was beneficial for the desorption of collector from mineral surface.Due to its simplicity and economy,the method we proposed of desorption of collector from mineral surface and its reuse for flotation has a great potential for industrial application.展开更多
Hydrogen desorption kinetics and characteristics,residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method.Results show that hydrogen desorption temperature and init...Hydrogen desorption kinetics and characteristics,residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method.Results show that hydrogen desorption temperature and initial hydrogen pressure affect hydrogen desorption characteristics of TC21 alloy.The hydrogen desorption process is mainly dominated by nucleation and growth process(kt=[-ln(1-α)]^(2/3)),chemical reaction process(kt=(1-α)^(-1/2))and three-dimensional diffusion process(kt=[1-(1-α)^(1/3)]^(1/2))when the hydrogenated TC21 alloy is dehydrogenated at temperatures of 700-940°C.When the hydrogenated TC21 alloy releases hydrogen,the following relationship exists among the rate constants of each process:k(chemical reaction process)>k(nucleation and growth process)>k(three-dimensional diffusion process).The residual hydrogen content of the hydrogenated TC21 alloy after hydrogen desorption decreases gradually with the increase in hydrogen desorption temperature,and increases gradually with the increase in the initial hydrogen pressure.The activation energy of TC21 alloy in the process of hydrogen desorption is about 26.663 kJ/mol.展开更多
Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments,and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics.I...Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments,and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics.In this study,three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene(PHE)and 1-hydroxyphenanthrene(1-OHPHE),and the effect of mucin on desorption was inves-tigated.The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites.With the increase of the cover de-gree,the adsorption of PHE decreased because of the decrease in hydrophobicity;while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond.The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+bridg-ing.The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity.Mucin promoted the desorption of PHE through competitive adsorption,and inhibit the desorption of 1-OHPHE through hydrophobic interaction,hydrogen bonding and Ca2+bridging.This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics,briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties,and emphasized the different environmental behaviors of pollutants.展开更多
This paper summarizes the mechanisms and environmental effects of interactions between microplastics and surfactants: surfactants adsorb onto microplastics surfaces through hydrophobic interactions and electrostatic f...This paper summarizes the mechanisms and environmental effects of interactions between microplastics and surfactants: surfactants adsorb onto microplastics surfaces through hydrophobic interactions and electrostatic forces, changing their surface properties and transport behavior. In addition, microplastics act as carriers influencing surfactant distribution. Environmental factors (pH, ionic strength, etc. ) significantly regulate this process. Current research still has limitations in areas such as desorption kinetics and combined pollution effects, necessitating in-depth studies under environmentally relevant conditions to provide a basis for risk assessment.展开更多
Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial,as restoration practices influence phosphorus(P)transformation and fractions and modify P...Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial,as restoration practices influence phosphorus(P)transformation and fractions and modify P adsorption behavior during the restoration process of degraded land.This study investigated the impacts of vegetation-based restoration practices on soil chemical and microbial parameters,P fractions,and patterns of P adsorption and desorption,and highlighted the combined influence on P availability.To evaluate the impact of vegetation-based restoration practices on P fractions and adsorption behavior in the semi-arid degraded land in India,this study compared three distinct tree-based restoration systems,including Leucaena leucocephala(Lam.)de Wit-based silviculture system(SCS),Acacia nilotica(L.)Willd.ex Delile-based silvopasture system(SPS),and Emblica officinalis Gaertn-based hortipasture system(HPS),with a natural grassland system(NGS)and a degraded fallow system(FS)as control.The soil samples across various soil depths(0-15,15-30,and 30-45 cm)were collected.The findings demonstrated that SCS,SPS,and HPS significantly improved soil organic carbon(SOC)and nutrient availability.Moreover,SCS and SPS resulted in increased microbial biomass phosphorus(MBP)content and phosphatase enzyme activity.The P fractionation analysis revealed that ferrum-associated phosphorus(Fe-P)was the major P fraction,followed by aluminum-associated phosphorus(Al-P),reflecting the dominance of ferrum(Fe)and aluminum(Al)oxides in the semi-arid degraded land.Compared with FS,vegetation-based restoration practices significantly increased various P fractions across soil depths.Additionally,P adsorption and desorption analysis indicated a lower adsorption capacity in tree-based restoration systems than in FS,with FS soils adsorbing higher P quantities in the adsorption phase but releasing less P during the desorption phase.This study revealed that degraded soils responded positively to ecological restoration in terms of P fraction and desorption behavior,influencing the resupply of P in restoration systems.Consequently,litter rich N-fixing tree-based restoration systems(i.e.,SCS and SPS)increased total phosphorus(TP)stock for plants and sustained the potential for long-term P supply in semi-arid ecosystems.With the widespread adoption of restoration practices across degraded landscapes,SCS and SPS would significantly contribute to soil restoration and improve productivity by maintaining the soil P supply in semi-arid ecosystems in India.展开更多
Although MgH_(2)is widely deemed to be the most promising solid-state hydrogen storage materials for the medium-high temperature fuelcell applications expected in the near future,the high-temperature desorption and sl...Although MgH_(2)is widely deemed to be the most promising solid-state hydrogen storage materials for the medium-high temperature fuelcell applications expected in the near future,the high-temperature desorption and sluggish hydrogen absorption/desorption kinetics are the major challenges for its applications.Herein,reduced graphene oxide/patronite nanoparticle composite(rGO@VS_(4))is successfully synthesized using an ionic liquid(IL)-assisted hydrothermal method,and superior catalytic effects originated from the rGO@VS_(4)composite precursor towards the hydrogen storage reaction of MgH_(2)are systematically investigated.The VS_(4)reacts with MgH_(2)leads to the in-situ formed and uniformly scattered of metallic V and MgS during both ball-milling and the initial hydrogen desorption,and the synergic catalytic effect of metallic V and MgS facilitates the improved hydrogen desorption of MgH_(2).The MgH_(2)-15 wt%rGO@VS_(4)composite starts releasing hydrogen at 180℃and peaks at 220℃,which is 145℃and 128℃lower than that of the Pristine MgH_(2),respectively.The energy required for H_(2)desorption from MgH_(2)is decreased to 63.8 kJ mol^(-1),58.9 kJ mol^(-1)lower than that of the Pristine MgH_(2).Furthermore,the MgH_(2)-15 wt%rGO@VS_(4)composite shows excellent cycling stability,of which reversible hydrogen capacity can stabilize at about 5.9 wt%with capacity retention of 98.2%at 300℃for 100 cycles.This study provides a deeper insight into metallic V and MgS to enhance the hydrogen desorption of solid-state hydrogen storage materials and also offers a perspective for the construction of high-activity catalysts for solid-state hydrogen storage materials.展开更多
Soil contamination remains a global problem,and numerous studies have been published for investigating soil re-mediation.Thermal desorption remediation(TDR)can significantly reduce the contaminants in the soil within ...Soil contamination remains a global problem,and numerous studies have been published for investigating soil re-mediation.Thermal desorption remediation(TDR)can significantly reduce the contaminants in the soil within a short time and consequently has been used worldwide.However,the soil properties respond to TDR differently and are dependent on the experimental set-up.The causative mechanisms of these differences are yet to be fully elucidated.A statistical meta-analysis was thus undertaken to evaluate the TDR treatment effects on soil properties and plant per-formance.This review pointed out that soil clay was reduced by 54.2%,while soil sand content was enhanced by 15.2% after TDR.This might be due to the release of cementing agents from clay minerals that resulted in the formation of soil aggregates.Soil electrical conductivity enhanced by 69.5% after TDR,which might be due to the heating-induced loss of structural hydroxyl groups and the consequent liberation of ions.The treatment of TDR leads to the reduction of plant germination rate,length,and biomass by 19.4%,44.8%,and 20.2%,respectively,compared to that of control soil.This might be due to the residue of contaminants and the loss of soil fertility during the thermal process that inhibited plant germination and growth.Soil pH and sulfate content increased with heating temperature increased,while soil enzyme activities decreased with thermal temperature increased.Overall,the results suggested that TDR treatment has inhibited plant growth as well as ecological restoration.展开更多
Catalytic amine-solvent regeneration has been validated as an energy-saving strategy for CO_(2) chemisorption by boosting reaction kinetics under mild conditions.The upscale performance evaluation and longterm durabil...Catalytic amine-solvent regeneration has been validated as an energy-saving strategy for CO_(2) chemisorption by boosting reaction kinetics under mild conditions.The upscale performance evaluation and longterm durability are indispensable steps for industrial application but have been scarcely reported thus far.Here,we report a ZrO_(2)/Al_(2)O_(3) pack catalyst that possesses strong metal oxide-support interactions,a porous structure,active and stable Zr-O-Al coordination,promoted proton transfer and a 40.7% decrease in the energy activation of carbamate decomposition,which significantly accelerates CO_(2) desorption kinetics.The upscale experiment and cost evaluation based on industrial flue gas revealed that the use of packing catalysts can reduce energy consumption by 27.56% and optimize the overall cost by 10.49%.The active sites present excellent stability in alkaline solvents.This work is the first to investigate the ability of high-technology readiness(technology readiness level at 6(TRL 6))for catalytic aminesolvent regeneration,providing valuable insights for potential applications involving efficient CO_(2) capture with catalyst assistance.展开更多
Ingestion of microplastics by various organisms has been widely evidenced.Chemicals associated with microplastics(MPs)may be released to digestive tracts upon ingestion.However,the effect of aging and temperature on t...Ingestion of microplastics by various organisms has been widely evidenced.Chemicals associated with microplastics(MPs)may be released to digestive tracts upon ingestion.However,the effect of aging and temperature on the chemical desorption for MPs remains poorly understood.The exposure of polyethylene(PE)particles to UV radiation in dry air,tap water,and sea water was conducted to mimic the aging process of MPs in different environments.Polychlorinated biphenyls(PCBs),as a typical hydrophobic organic contaminant,were preloaded in these aged and pristine PE.The desorption was performed by exposing preloaded PE particles in simulated gastric and gut fluids at 25℃and 40℃.After UV aging,the average diameter of PE particles decreased rapidly with aging time,indicating continuously fragmentation of PE under UV exposure.The desorption of PCBs from PE particles under different conditions varied from 7%to 40%,and that from aged PE in gut fluid at 37℃was significantly higher than those under other conditions(P<0.05).Furthermore,a clear declining trend was observed as lg K_(ow)(octanol-water partition coefficient)value increased.The aging process,hydrophobicity of chemicals,and incubation temperature were important factors on the desorption of PCBs from PE.The present study helps understand the desorption of PCBs from microplastics and the potential risks of microplastics ingestion by organisms.展开更多
The Cr（III） desorption experiments of Gaomiaozi （GMZ） bentonite in aqueous solutions were performed. The variables affecting the desorption behaviors, such as contact time, concentration of the desorbent, pH value...The Cr（III） desorption experiments of Gaomiaozi （GMZ） bentonite in aqueous solutions were performed. The variables affecting the desorption behaviors, such as contact time, concentration of the desorbent, pH value of the solution, temperature and desorption isotherms, were investigated by the batch experiments. The results show that the adsorbed Cr（III） on GMZ bentonite can be easily extracted by the desorbent. Kinetics examination shows that desorption is slower than adsorption, and the desorption rate increases with time and reaches the equilibrium after 3 h. The final desorption ratios of Cr（III） are 89.4%, 56.5%and 77.2%in the desorption solution with 0.1 mol/L HCl, 1 mol/L NaCl, and 1 mol/L CaCl2, respectively, and the concentration can promote the desorption progress. Furthermore, the results of successive regeneration cycles indicate that the bentonite has a good regeneration ability and reusability. The pH value is an important factor in the Cr（III） desorption from the GMZ bentonite. The results of adsorption and desorption isotherms show that both adsorption and desorption isotherms are consistent with the Freundlich equation. The comparison of adsorption and desorption isotherms implies that the adsorption/desorption hysteresis is negligible and the transport of Cr（III） in bentonite can be described by a reversible adsorption process.展开更多
[Objective]The aim of this paper was to provide theoretical basis for study on enhancement of surfactants to desorption of PCBs from soil. [Method]The desorption effects of surfactants SDBs,Tween 80,HTAB on PCBs were ...[Objective]The aim of this paper was to provide theoretical basis for study on enhancement of surfactants to desorption of PCBs from soil. [Method]The desorption effects of surfactants SDBs,Tween 80,HTAB on PCBs were studied as well as their distribution in water and soil. Effects of rationing on desorption of PCBs were also analyzed. [Result]The potential of single surfactant to enhance the desorption of PCBs from soil in order was Tween 80 SDBS HTAB. Three surfactants were largely adsorbed on soil and the sorption followed HTABTween 80SDBS. The desorption of PCBs increased significantly and linearly with the increase of aqueous micelle concentration of surfactants. [Conclusion]Enhancing effect of three surfactants on PCBs desorption were obtained,which will provide theoretical basis for further analyzing.展开更多
The Mg-Ni hydride was prepared by hydriding combustion synthesis under a high magnetic field. The dehydriding kinetics of the hydrides was measured under the isothermal and non-isothermal conditions. A model was appli...The Mg-Ni hydride was prepared by hydriding combustion synthesis under a high magnetic field. The dehydriding kinetics of the hydrides was measured under the isothermal and non-isothermal conditions. A model was applied to analyzing the kinetics behavior of Mg-Ni hydride. The calculation results show that the theoretical value and the experimental data can reach a good agreement, especially in the case of non-isothermal dehydriding. The rate-controlling step is the diffusion of hydrogen atoms in the solid solution. The sample prepared under magnetic field of 6 T under the isothermal condition can reach the best performance. The similar tendency was observed under the non-isothermal condition and the reason was discussed.展开更多
[Objective]The research aimed to provide scientific reference for reasonable utilization of polyacrylamide(PAM).[Method]After PAM treatment,the soil aggregates were classified through dry sieve analysis and the adsorp...[Objective]The research aimed to provide scientific reference for reasonable utilization of polyacrylamide(PAM).[Method]After PAM treatment,the soil aggregates were classified through dry sieve analysis and the adsorption capacity and desorption capacity of all soil aggregates to phosphorus at different phosphorus concentrations were analyzed.[Result] The phosphorus adsorption and desorption of soil sample treated by PAM declined. The amount of phosphorus adsorption increased with the increase of phosphorus concentration and this increase was fast in low phosphorus concentration area but slow in high phosphorus concentration area.At different phosphorus concentrations,adsorption showed a へ shape changing trend.The phosphorus adsorption was related to phosphorus concentration and the 2-3 mm aggregate had the highest desorption rate while 0.1-0.25 mm aggregate and 0.45-1 mm aggregate had lowest desorption rate.[Conclusion]The PAM treatment generated significant influence on phosphorus adsorption and analytic features of aggregate in all size fractions.展开更多
An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization,...An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.展开更多
The adsorption and desorption of isoliquiritigenin and liquiritigenin to different types of carbon nanotubes （CNTs） were comparatively studied in this study. The pore structure, specific surface area, surface morpho...The adsorption and desorption of isoliquiritigenin and liquiritigenin to different types of carbon nanotubes （CNTs） were comparatively studied in this study. The pore structure, specific surface area, surface morphologies and functional groups of the CNTs were tested by N2 adsorption, scanning electron microscope （SEM） and infrared spectra （IR）. The investigation of dynamic adsorption, isothermal equilibrium adsorption and desorption of isoliquiritigenin and liquiritigenin to CNTs demonstrated that the adsorption amount on oxidized multi-walled carbon nanotubes （o-MWCNTs） was greater than that on raw multi-walled carbon nanotubes （r-MWCNTs）, especially the adsorption of isoliquiritigenin to o-MWCNTs. The data of equilibrium adsorption were better represented by the Freundlich isotherm model. In addition, the adsorbed amount per unit CNTs was decreased when the temperature got higher. From the results of isothermal equilibrium adsorption and desorption to CNTs, it could be inferred that o-MWCNTs had higher adsorption to isoliquiritigenin and liquiritigenin than r-MWCNTs. Additionally, o-MWCNTs had a better desorption efficiency to isoliquiritigenin and liquiritigenin （about 48.57% and 32.86%） than r-MWCNTs （about 24.56% and 17.46%）.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42330703 and 42177194)Zhejiang Provincial Natural Science Foundation of China(No.LMS25D030001).
文摘Cadmium(Cd)contamination in soils poses substantial environmental and health risks globally,with manganese(Mn)playing a crucial role in regulating Cd mobility through soil adsorption processes and shared crop uptake pathways.While the importance of understanding Cd-Mn dynamics in soils is widely recognized,quantitative assessments of their correlated desorption processes remain limited.This study employed diffusive gradients in thin-films(DGT)technique combined with DGT-induced fluxes in soils(DIFS)modeling to investigate Cd and Mn availability and desorption dynamics in karst soils from Guangxi,southwestern China.The soil solution concentrations ranged from 0.23–1.82μg/L for Cd and 1.29–8.41 mg/L for Mn.DGT measurements demonstrated nonlinear accumulation patterns for both metals over 48 h duration.DIFS modeling yielded distribution coefficients(Kdl)ranging from 2.50 to 807 mL/g and response time(Tc)between 1.27 and 425 s for both metals.Solid phase resupply was limited by desorption rates of 5.38–229×10^(−5)/s,providing unprecedented insight into the kinetics of metal release in these soils.Analysis of metal desorption rate ratios(k−1-Mn/k−1-Cd)indicated that soil organic matter content,clay content,pH,and metal contents collectively control Cd and Mn desorption kinetics,leading to distinct desorption patterns across soils with varying physicochemical properties.These findings demonstrate rapid equilibrium reestablishment and desorption-limited resupply characteristics of Cd and Mn in karst soils,advancing understanding of correlative metal behaviors in these unique geological settings.
基金financially supported by the National Natural Science Foundation of China(Nos.52304314 and U23A20602)the Open Fund of the Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Ministry of Ecology and Environment+3 种基金China(No.HB202406)the Fundamental Research Funds for the Central Universities of Central South University,China(Nos.CX20240021 and 2024ZZTS0008)the Innovation and Entrepreneurship Funding Project for College Students of Central South UniversityChina(No.S202410533166)。
文摘Flotation is the most common method to recover valuable minerals by selective adsorption of collectors on target mineral surfaces.However,in subsequent hydrometallurgy of mineral flotation concentrates,the adsorbed collectors must be desorbed since it can adversely affect the efficiency of metallurgical process and produce wastewater.ZL,as a fatty acid mixture,is a typical industrially used collector for scheelite flotation in China.Sodium oleate(NaOL)has similar fatty acid group as ZL.In this study,the desorption behavior of NaOL/ZL from scheelite surface by a physical method of stirring at a low temperature was investigated.NaOL desorption tests of single mineral showed that a desorption rate of 77.75% for NaOL from scheelite surface into pulp was achieved in a stirring speed of2500 r/min at 5℃in a neutral environment.Under the above desorption condition,in the pulp containing desorbed collector by adding extra 30% normal NaOL dosage,the scheelite recovery reached about 95% in the single mineral flotation test.Desorption and reuse of ZL collector for the flotation of real scheelite ore showed only a 75%normal dosage of ZL could produce a qualified rough concentrate.The atomic force microscope(AFM)tests showed that after desorption treatment of low temperature and strong stirring,the dense strip-like structure of NaOL on the scheelite surface was destroyed to be speck-like.Molecular dynamics simulations(MDS)demonstrated that the adsorption energy between NaOL and scheelite surface was more negative at 25℃(-13.39 kcal/mol)than at 5℃(-11.50 kcal/mol)in a neutral pH,indicating that a low temperature was beneficial for the desorption of collector from mineral surface.Due to its simplicity and economy,the method we proposed of desorption of collector from mineral surface and its reuse for flotation has a great potential for industrial application.
基金National Natural Science Foundation of China(52275328,51875157)。
文摘Hydrogen desorption kinetics and characteristics,residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method.Results show that hydrogen desorption temperature and initial hydrogen pressure affect hydrogen desorption characteristics of TC21 alloy.The hydrogen desorption process is mainly dominated by nucleation and growth process(kt=[-ln(1-α)]^(2/3)),chemical reaction process(kt=(1-α)^(-1/2))and three-dimensional diffusion process(kt=[1-(1-α)^(1/3)]^(1/2))when the hydrogenated TC21 alloy is dehydrogenated at temperatures of 700-940°C.When the hydrogenated TC21 alloy releases hydrogen,the following relationship exists among the rate constants of each process:k(chemical reaction process)>k(nucleation and growth process)>k(three-dimensional diffusion process).The residual hydrogen content of the hydrogenated TC21 alloy after hydrogen desorption decreases gradually with the increase in hydrogen desorption temperature,and increases gradually with the increase in the initial hydrogen pressure.The activation energy of TC21 alloy in the process of hydrogen desorption is about 26.663 kJ/mol.
基金supported by the National Natural Science Foundation of China(Nos.42077337 and 42277228)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515011560)the Science and Technology Planning Project of Guangzhou(Nos.202002030297 and 202002020072).
文摘Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments,and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics.In this study,three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene(PHE)and 1-hydroxyphenanthrene(1-OHPHE),and the effect of mucin on desorption was inves-tigated.The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites.With the increase of the cover de-gree,the adsorption of PHE decreased because of the decrease in hydrophobicity;while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond.The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+bridg-ing.The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity.Mucin promoted the desorption of PHE through competitive adsorption,and inhibit the desorption of 1-OHPHE through hydrophobic interaction,hydrogen bonding and Ca2+bridging.This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics,briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties,and emphasized the different environmental behaviors of pollutants.
基金Supported by Zhaoqing University Innovation and Entrepreneurship Training Program for College Students (X202410580130).
文摘This paper summarizes the mechanisms and environmental effects of interactions between microplastics and surfactants: surfactants adsorb onto microplastics surfaces through hydrophobic interactions and electrostatic forces, changing their surface properties and transport behavior. In addition, microplastics act as carriers influencing surfactant distribution. Environmental factors (pH, ionic strength, etc. ) significantly regulate this process. Current research still has limitations in areas such as desorption kinetics and combined pollution effects, necessitating in-depth studies under environmentally relevant conditions to provide a basis for risk assessment.
基金funded by Indian Council of Agricultural Research,Ministry of Agriculture and Farmers Welfare,India(AGRIL.EDN/1/1/2022-EXAM CELL).
文摘Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial,as restoration practices influence phosphorus(P)transformation and fractions and modify P adsorption behavior during the restoration process of degraded land.This study investigated the impacts of vegetation-based restoration practices on soil chemical and microbial parameters,P fractions,and patterns of P adsorption and desorption,and highlighted the combined influence on P availability.To evaluate the impact of vegetation-based restoration practices on P fractions and adsorption behavior in the semi-arid degraded land in India,this study compared three distinct tree-based restoration systems,including Leucaena leucocephala(Lam.)de Wit-based silviculture system(SCS),Acacia nilotica(L.)Willd.ex Delile-based silvopasture system(SPS),and Emblica officinalis Gaertn-based hortipasture system(HPS),with a natural grassland system(NGS)and a degraded fallow system(FS)as control.The soil samples across various soil depths(0-15,15-30,and 30-45 cm)were collected.The findings demonstrated that SCS,SPS,and HPS significantly improved soil organic carbon(SOC)and nutrient availability.Moreover,SCS and SPS resulted in increased microbial biomass phosphorus(MBP)content and phosphatase enzyme activity.The P fractionation analysis revealed that ferrum-associated phosphorus(Fe-P)was the major P fraction,followed by aluminum-associated phosphorus(Al-P),reflecting the dominance of ferrum(Fe)and aluminum(Al)oxides in the semi-arid degraded land.Compared with FS,vegetation-based restoration practices significantly increased various P fractions across soil depths.Additionally,P adsorption and desorption analysis indicated a lower adsorption capacity in tree-based restoration systems than in FS,with FS soils adsorbing higher P quantities in the adsorption phase but releasing less P during the desorption phase.This study revealed that degraded soils responded positively to ecological restoration in terms of P fraction and desorption behavior,influencing the resupply of P in restoration systems.Consequently,litter rich N-fixing tree-based restoration systems(i.e.,SCS and SPS)increased total phosphorus(TP)stock for plants and sustained the potential for long-term P supply in semi-arid ecosystems.With the widespread adoption of restoration practices across degraded landscapes,SCS and SPS would significantly contribute to soil restoration and improve productivity by maintaining the soil P supply in semi-arid ecosystems in India.
基金supported by the National Key Research and Development Program of China(2022YFB3803801)National Natural Science Foundation of China(Grant No.52201275,52301287,52307250)+1 种基金Two-chain integration key project of Shaanxi Province(Grant No.2021LLRH-09)Young Talent Fund of Association for Science and Technology in Shaanxi,China(No.20220456).
文摘Although MgH_(2)is widely deemed to be the most promising solid-state hydrogen storage materials for the medium-high temperature fuelcell applications expected in the near future,the high-temperature desorption and sluggish hydrogen absorption/desorption kinetics are the major challenges for its applications.Herein,reduced graphene oxide/patronite nanoparticle composite(rGO@VS_(4))is successfully synthesized using an ionic liquid(IL)-assisted hydrothermal method,and superior catalytic effects originated from the rGO@VS_(4)composite precursor towards the hydrogen storage reaction of MgH_(2)are systematically investigated.The VS_(4)reacts with MgH_(2)leads to the in-situ formed and uniformly scattered of metallic V and MgS during both ball-milling and the initial hydrogen desorption,and the synergic catalytic effect of metallic V and MgS facilitates the improved hydrogen desorption of MgH_(2).The MgH_(2)-15 wt%rGO@VS_(4)composite starts releasing hydrogen at 180℃and peaks at 220℃,which is 145℃and 128℃lower than that of the Pristine MgH_(2),respectively.The energy required for H_(2)desorption from MgH_(2)is decreased to 63.8 kJ mol^(-1),58.9 kJ mol^(-1)lower than that of the Pristine MgH_(2).Furthermore,the MgH_(2)-15 wt%rGO@VS_(4)composite shows excellent cycling stability,of which reversible hydrogen capacity can stabilize at about 5.9 wt%with capacity retention of 98.2%at 300℃for 100 cycles.This study provides a deeper insight into metallic V and MgS to enhance the hydrogen desorption of solid-state hydrogen storage materials and also offers a perspective for the construction of high-activity catalysts for solid-state hydrogen storage materials.
基金the financial sponsorship from the National Key R&D Program of China(No.2023YFC3905800)Youth Innovation Promotion Association CAS(2021349)+5 种基金Guangdong Youth Talent Support Program(2021TQ06L121)State Key Laboratory of Subtropical Building Science in South China University of Technology(2022ZC01)Shenzhen Science and Technology Program(KCXFZ20211020163816023)financially supported by the Natural Science Foundation of Wuhan(No.2024040801020271)the Fundamental Research Funds for Central Public Welfare Research Institutes(No.CKSF20241004/YT)the support from FINNCERES flagship and tenure track fund(91160169(TT/Bordoloi)。
文摘Soil contamination remains a global problem,and numerous studies have been published for investigating soil re-mediation.Thermal desorption remediation(TDR)can significantly reduce the contaminants in the soil within a short time and consequently has been used worldwide.However,the soil properties respond to TDR differently and are dependent on the experimental set-up.The causative mechanisms of these differences are yet to be fully elucidated.A statistical meta-analysis was thus undertaken to evaluate the TDR treatment effects on soil properties and plant per-formance.This review pointed out that soil clay was reduced by 54.2%,while soil sand content was enhanced by 15.2% after TDR.This might be due to the release of cementing agents from clay minerals that resulted in the formation of soil aggregates.Soil electrical conductivity enhanced by 69.5% after TDR,which might be due to the heating-induced loss of structural hydroxyl groups and the consequent liberation of ions.The treatment of TDR leads to the reduction of plant germination rate,length,and biomass by 19.4%,44.8%,and 20.2%,respectively,compared to that of control soil.This might be due to the residue of contaminants and the loss of soil fertility during the thermal process that inhibited plant germination and growth.Soil pH and sulfate content increased with heating temperature increased,while soil enzyme activities decreased with thermal temperature increased.Overall,the results suggested that TDR treatment has inhibited plant growth as well as ecological restoration.
基金supported by the National Natural Science Foundation of China(52300134 and 22106084)the China Postdoctoral Science Foundation(2022TQ0175,2023M741931,and 2022T150350).
文摘Catalytic amine-solvent regeneration has been validated as an energy-saving strategy for CO_(2) chemisorption by boosting reaction kinetics under mild conditions.The upscale performance evaluation and longterm durability are indispensable steps for industrial application but have been scarcely reported thus far.Here,we report a ZrO_(2)/Al_(2)O_(3) pack catalyst that possesses strong metal oxide-support interactions,a porous structure,active and stable Zr-O-Al coordination,promoted proton transfer and a 40.7% decrease in the energy activation of carbamate decomposition,which significantly accelerates CO_(2) desorption kinetics.The upscale experiment and cost evaluation based on industrial flue gas revealed that the use of packing catalysts can reduce energy consumption by 27.56% and optimize the overall cost by 10.49%.The active sites present excellent stability in alkaline solvents.This work is the first to investigate the ability of high-technology readiness(technology readiness level at 6(TRL 6))for catalytic aminesolvent regeneration,providing valuable insights for potential applications involving efficient CO_(2) capture with catalyst assistance.
基金Supported by the National Natural Science Foundation of China(No.21936004)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2021SP208)the Fundamental Research Funds for the Central Universities(No.21623118)。
文摘Ingestion of microplastics by various organisms has been widely evidenced.Chemicals associated with microplastics(MPs)may be released to digestive tracts upon ingestion.However,the effect of aging and temperature on the chemical desorption for MPs remains poorly understood.The exposure of polyethylene(PE)particles to UV radiation in dry air,tap water,and sea water was conducted to mimic the aging process of MPs in different environments.Polychlorinated biphenyls(PCBs),as a typical hydrophobic organic contaminant,were preloaded in these aged and pristine PE.The desorption was performed by exposing preloaded PE particles in simulated gastric and gut fluids at 25℃and 40℃.After UV aging,the average diameter of PE particles decreased rapidly with aging time,indicating continuously fragmentation of PE under UV exposure.The desorption of PCBs from PE particles under different conditions varied from 7%to 40%,and that from aged PE in gut fluid at 37℃was significantly higher than those under other conditions(P<0.05).Furthermore,a clear declining trend was observed as lg K_(ow)(octanol-water partition coefficient)value increased.The aging process,hydrophobicity of chemicals,and incubation temperature were important factors on the desorption of PCBs from PE.The present study helps understand the desorption of PCBs from microplastics and the potential risks of microplastics ingestion by organisms.
基金Project(41272287)supported by the National Natural Science Foundation of ChinaProject(13PJD029)supported by Shanghai Pujiang ProgramProject(SKLGDUEK1202)supported by State Key Laboratory for GeoMechanics and Deep Underground Engineering,China
文摘The Cr（III） desorption experiments of Gaomiaozi （GMZ） bentonite in aqueous solutions were performed. The variables affecting the desorption behaviors, such as contact time, concentration of the desorbent, pH value of the solution, temperature and desorption isotherms, were investigated by the batch experiments. The results show that the adsorbed Cr（III） on GMZ bentonite can be easily extracted by the desorbent. Kinetics examination shows that desorption is slower than adsorption, and the desorption rate increases with time and reaches the equilibrium after 3 h. The final desorption ratios of Cr（III） are 89.4%, 56.5%and 77.2%in the desorption solution with 0.1 mol/L HCl, 1 mol/L NaCl, and 1 mol/L CaCl2, respectively, and the concentration can promote the desorption progress. Furthermore, the results of successive regeneration cycles indicate that the bentonite has a good regeneration ability and reusability. The pH value is an important factor in the Cr（III） desorption from the GMZ bentonite. The results of adsorption and desorption isotherms show that both adsorption and desorption isotherms are consistent with the Freundlich equation. The comparison of adsorption and desorption isotherms implies that the adsorption/desorption hysteresis is negligible and the transport of Cr（III） in bentonite can be described by a reversible adsorption process.
基金Supported by the National Natural Science Fund (20947003)~~
文摘[Objective]The aim of this paper was to provide theoretical basis for study on enhancement of surfactants to desorption of PCBs from soil. [Method]The desorption effects of surfactants SDBs,Tween 80,HTAB on PCBs were studied as well as their distribution in water and soil. Effects of rationing on desorption of PCBs were also analyzed. [Result]The potential of single surfactant to enhance the desorption of PCBs from soil in order was Tween 80 SDBS HTAB. Three surfactants were largely adsorbed on soil and the sorption followed HTABTween 80SDBS. The desorption of PCBs increased significantly and linearly with the increase of aqueous micelle concentration of surfactants. [Conclusion]Enhancing effect of three surfactants on PCBs desorption were obtained,which will provide theoretical basis for further analyzing.
基金Project(51464008) supported by the National Natural Science Foundation of ChinaProject(KY[2012]004) supported by the Key Laboratory Item of Education Office in Guizhou Province,China
文摘The Mg-Ni hydride was prepared by hydriding combustion synthesis under a high magnetic field. The dehydriding kinetics of the hydrides was measured under the isothermal and non-isothermal conditions. A model was applied to analyzing the kinetics behavior of Mg-Ni hydride. The calculation results show that the theoretical value and the experimental data can reach a good agreement, especially in the case of non-isothermal dehydriding. The rate-controlling step is the diffusion of hydrogen atoms in the solid solution. The sample prepared under magnetic field of 6 T under the isothermal condition can reach the best performance. The similar tendency was observed under the non-isothermal condition and the reason was discussed.
文摘[Objective]The research aimed to provide scientific reference for reasonable utilization of polyacrylamide(PAM).[Method]After PAM treatment,the soil aggregates were classified through dry sieve analysis and the adsorption capacity and desorption capacity of all soil aggregates to phosphorus at different phosphorus concentrations were analyzed.[Result] The phosphorus adsorption and desorption of soil sample treated by PAM declined. The amount of phosphorus adsorption increased with the increase of phosphorus concentration and this increase was fast in low phosphorus concentration area but slow in high phosphorus concentration area.At different phosphorus concentrations,adsorption showed a へ shape changing trend.The phosphorus adsorption was related to phosphorus concentration and the 2-3 mm aggregate had the highest desorption rate while 0.1-0.25 mm aggregate and 0.45-1 mm aggregate had lowest desorption rate.[Conclusion]The PAM treatment generated significant influence on phosphorus adsorption and analytic features of aggregate in all size fractions.
文摘An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.
基金National Natural Science Foundation of China (Grant No.30960515)Technological Innovation of Natural Science Project of Shihezi University(Grant No.ZRKX2008064 and No.ZRKX2008067)
文摘The adsorption and desorption of isoliquiritigenin and liquiritigenin to different types of carbon nanotubes （CNTs） were comparatively studied in this study. The pore structure, specific surface area, surface morphologies and functional groups of the CNTs were tested by N2 adsorption, scanning electron microscope （SEM） and infrared spectra （IR）. The investigation of dynamic adsorption, isothermal equilibrium adsorption and desorption of isoliquiritigenin and liquiritigenin to CNTs demonstrated that the adsorption amount on oxidized multi-walled carbon nanotubes （o-MWCNTs） was greater than that on raw multi-walled carbon nanotubes （r-MWCNTs）, especially the adsorption of isoliquiritigenin to o-MWCNTs. The data of equilibrium adsorption were better represented by the Freundlich isotherm model. In addition, the adsorbed amount per unit CNTs was decreased when the temperature got higher. From the results of isothermal equilibrium adsorption and desorption to CNTs, it could be inferred that o-MWCNTs had higher adsorption to isoliquiritigenin and liquiritigenin than r-MWCNTs. Additionally, o-MWCNTs had a better desorption efficiency to isoliquiritigenin and liquiritigenin （about 48.57% and 32.86%） than r-MWCNTs （about 24.56% and 17.46%）.
