In this study,chitosan(CS)was combined with microcrystalline cellulose(MCC)to fabricate composite hydrogel beads.These beads were further modified through blending and grafting with polyethyleneimine(PEI)to develop ch...In this study,chitosan(CS)was combined with microcrystalline cellulose(MCC)to fabricate composite hydrogel beads.These beads were further modified through blending and grafting with polyethyleneimine(PEI)to develop chitosan/microcrystalline cellulose@polyethyleneimine(CS/MCC@PEI)composite gel spheres for the efficient adsorption of diclofenac sodium(DS)from aqueous solutions.The adsorbent was characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),X-ray pho-toelectron spectroscopy(XPS),and thermogravimetric analysis(TGA).The CS/MCC@PEI composite exhibited a spherical morphology with a porous structure,abundant surface functional groups,and a high adsorption capac-ity of 274.84 mg/g for DS.Kinetic studies revealed that the adsorption process followed the pseudo-second-order model,dominated by physical adsorption,with both surface and internal diffusion influencing the adsorption rate.The Freundlich isotherm model best described the adsorption behavior,indicating multilayer adsorption on heterogeneous surfaces.Environmental adaptability tests demonstrated minimal interference from co-existing anions and humic acid,while regeneration experiments confirmed excellent reusability(>77%removal after five cycles).The adsorption mechanism involved electrostatic interactions and hydrogen bonding between the hydroxyl/amino groups of the composite and DS.These findings highlight the potential of CS/MCC@PEI as a cost-effective and sustainable adsorbent for DS removal from water.展开更多
The flotation separation of argentite from sphalerite using ammonium dibutyl dithiophosphate(ADD)was studied.Molecular simulation(MS)calculation shows that ADD is chemisorbed on argentite and sphalerite surface in the...The flotation separation of argentite from sphalerite using ammonium dibutyl dithiophosphate(ADD)was studied.Molecular simulation(MS)calculation shows that ADD is chemisorbed on argentite and sphalerite surface in the form of S—P bond.The ADD adsorption on argentite and sphalerite surface in Ag^(+)system was revealed by ICP,Zeta potential and XPS analyses.It is shown that the dissolved Ag^(+)from argentite surface can be absorbed on sphalerite surface in the form of silver hydroxide,and AgOH hydrophilic colloid prevents the adsorption of ADD on sphalerite surface.The ADD adsorption on argentite and sphalerite surface in the pulp containing silver and zinc ions was revealed by adsorption capacity and surface wettability analyses.It is shown that the combined Zn(OH)_(2) and AgOH hydrophilic colloid leads to greater ADD adsorption capacity on argentite surface and stronger surface hydrophobicity than sphalerite.Flotation tests demonstrate that ADD enables efficient separation of argentite from sphalerite in the pulp containing silver and zinc ions.展开更多
This study presents a thorough investigation into the use of single and twin-tailed cationic and anionic surfactant-modified chitosan(SMCS)hydrogel beads as effective adsorbents for the elimination of hazardous polycy...This study presents a thorough investigation into the use of single and twin-tailed cationic and anionic surfactant-modified chitosan(SMCS)hydrogel beads as effective adsorbents for the elimination of hazardous polycyclic aromatic hydrocarbons(PAHs)from aqueous solutions.The Chitosan(CS)hydrogel beads were modified with single/twin-tailed anionic surfactants,sodium dodecyl sulfate(SDS)and sodium bis(2-ethylhexyl)sulfosuccinate(AOT),and cationic surfactants,dodecyltrimethylammonium bromide(DTAB)and didodecyldimethylammonium bromide(DDAB),to enhance their adsorption capacity of PAHs.The CS and SMCS beads were evaluated for their structural,mechanical,and adsorption properties using a range of techniques,including infrared spectroscopy(IR),energy-dispersive X-ray spectroscopy(EDX),rheometry,and field emission scanning electron microscopy(FESEM).Adsorption experiments of naphthalene(Nap),acenaphthene(Ace),and phenanthrene(Phe)on SMCS beads demonstrate that they have significantly higher adsorption capacities than CS beads,due to increase in hydrophobic interactions.Adsorption capacity followed the trend,Phen>Ace>Nap for all the beads revealing that twin-tailed SMCS bead possess much higher adsorption capacities(Qmax)compared to single-tailed SMCS beads.For twin tailed surfactants,the maximum adsorption capacities for Nap,Ace and Phe varied as CS-AOT(CS-DDAB):430.0(323.8)611.60(538.18)633.39(536.99)mg/g respectively,outperforming other reported hydrogel beads.The study highlights the simplicity,eco-friendliness,and enhanced performance of surfactant modification for developing high-efficiency adsorbents,paving the way for cost-effective solutions in water re-mediation.展开更多
In order to address the evolving emission characteristics of oxygenated volatile organic compounds(OVOCs),it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with...In order to address the evolving emission characteristics of oxygenated volatile organic compounds(OVOCs),it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with large kinetic diameters.In this study,we used co-pyrolysis to prepare a series of graded porous carbon materials with well-developed micropores by adjusting the doping ratios of root nodules and pretreated cellulose.The material with root nodule to cellulose mass ratio of 1:1(TCC-RN-1)exhibited the highest saturated adsorption capacity for butyl acetate(834 mg/g).This can be attributed to enhanced pore size distribution from nodule doping,which facilitates the development of a micropore-graded structure.Additionally,the nodules acted as auxiliary activating agents that enhanced the KOH micropore regulation effect during the activation stage,resulting in the highest micropore volume(0.863 cm^(3)/g).The doping of root nodules facilitated the formation of additional defects on the surface of the porous carbon material,leading to a more disordered arrangement that improved pollutant adsorption.Furthermore,TCC-RN-1 demonstrated good thermal stability in an air atmosphere,main-taining a butyl acetate adsorption capacity exceeding 95%after five adsorption-desorption cycles.This indicates its favorable potential for industrial applications.展开更多
Porous carbon microspheres are widely regarded as a superior CO_(2) adsorbent due to their exceptional efficiency and affordability.However,better adsorption performance is very attractive for porous carbon microspher...Porous carbon microspheres are widely regarded as a superior CO_(2) adsorbent due to their exceptional efficiency and affordability.However,better adsorption performance is very attractive for porous carbon microspheres.And modification of the pore structure is one of the effective strategies.In this study,multi-cavity mesoporous carbon microspheres were successfully synthesized by the synergistic method of soft and hard templates,during which a phenolic resin with superior thermal stability was employed as the carbon precursor and a mixture of silica sol and F108 as the mesoporous template.Carbon microspheres with multi-cavity mesoporous structures were prepared,and all the samples showed highly even mesopores,with diameters around 12 nm.The diameter of these microspheres decreased from 396.8 nm to about 182.5 nm with the increase of silica sol.After CO_(2) activation,these novel carbon microspheres(APCF0.5-S1.75)demonstrated high specific surface area(983.3 m^(2)/g)and remarkable CO_(2) uptake of 4.93 mmol/g at 0℃ and1 bar.This could be attributed to the unique multi-cavity structure,which offers uniform mesoporous pore channels,minimal CO_(2) transport of and a greater number of active sites for CO_(2) adsorption.展开更多
Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation.However,the requirement of highly pure H_(2)for re-hydrogenation limits its wide application.Here,amorphou...Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation.However,the requirement of highly pure H_(2)for re-hydrogenation limits its wide application.Here,amorphous Al_(2)O_(3)shells(10 nm)were deposited on the surface of highly active hydrogen storage material particles(MgH_(2)-ZrTi)by atomic layer deposition to obtain MgH_(2)-ZrTi@Al_(2)O_(3),which have been demonstrated to be air stable with selective adsorption of H_(2)under a hydrogen atmosphere with different impurities(CH_(4),O_(2),N_(2),and CO_(2)).About 4.79 wt%H_(2)was adsorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)at 75℃under 10%CH_(4)+90%H_(2)atmosphere within 3 h with no kinetic or density decay after 5 cycles(~100%capacity retention).Furthermore,about 4 wt%of H_(2)was absorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)under 0.1%O_(2)+0.4%N_(2)+99.5%H_(2)and 0.1%CO_(2)+0.4%N_(2)+99.5%H_(2)atmospheres at 100℃within 0.5 h,respectively,demonstrating the selective hydrogen absorption of MgH_(2)-ZrTi@10nmAl_(2)O_(3)in both oxygen-containing and carbon dioxide-containing atmospheres hydrogen atmosphere.The absorption and desorption curves of MgH_(2)-ZrTi@10nmAl_(2)O_(3)with and without absorption in pure hydrogen and then in 21%O_(2)+79%N_(2)for 1 h were found to overlap,further confirming the successful shielding effect of Al_(2)O_(3)shells against O_(2)and N_(2).The MgH_(2)-ZrTi@10nmAl_(2)O_(3)has been demonstrated to be air stable and have excellent selective hydrogen absorption performance under the atmosphere with CH_(4),O_(2),N_(2),and CO_(2).展开更多
Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundame...Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundamental understanding on how they control the electrochemical performances.Herein,by harnessing the electrostatic adsorption of one-dimensional nanofiller(i.e.,surface-charged halloysite nanotubes,d-HNTs),we successfully fabricate a high-performance polymer nanocomposite electrolyte enabled by strong surface adsorption,referred as adsorption-state polymer electrolyte(ASPE).This ASPE shows fast ion transport(0.71±0.05 mS cm^(-1)at room temperature),high mechanical strength and toughness(10.3±0.05 MPa;15.73 MJ m^(-3)),improved lithium-ion transference number,and long cycle life with lithium metal anode,in comparison with the sample without the d-HNT adsorption effect.To fundamentally understand these high performances,an anion-rich asymmetric solvent structure model is further proposed and evidenced by both experiments and simulation studies.Results show that the electrostatic adsorption among the d-HNT,ionic liquid electrolyte,and polymer chain generates a nano filler-supported fast ion-conduction pathway with asymmetric Li+-coordination microenvironment.Meanwhile,the anion-rich asymmetric solvent structure model of ASPE also generates a fast de-solvation and anion-derived stable solid-electrolyte interphase for lithium metal anode.The high performance and understanding of the mechanism for ASPE provide a promising path to develop advanced polymer electrolytes.展开更多
Adsorption by solid amine adsorbent is a promising technology for decarbonization of flue gas.However,adsorption properties of many solid amine adsorbents need to be enhanced,and it is necessary to further study the C...Adsorption by solid amine adsorbent is a promising technology for decarbonization of flue gas.However,adsorption properties of many solid amine adsorbents need to be enhanced,and it is necessary to further study the CO_(2)adsorption mechanism.A novel CO_(2)adsorbent with high capacity was obtained by grafting 3-aminopropyltriethoxysilane(APTES)on a micro-mesoporous composite molecular sieve ZSM-5/MCM-48 as the support,and then impregnated with tetraethylenepentamine(TEPA)or polyethyleneimine(PEI).The maximum adsorption capacity of APTES-ZSM-5/MCM-48-TEPA-60(A-ZM-T60),loaded with 60%(in mass)TEPA,for CO_(2)reaches 5.82 mmol·g^(-1) at 60℃in 15%(in volume)CO_(2).Carbamate,alkyl ammonium carbamate and carbonate are generated during the chemical adsorption,which is dominant for CO_(2)adsorption because of the reaction between CO_(2)and amino groups on the adsorbent,simultaneously accompanied by weak physical adsorption.All above data confirm that these composites display an outstanding adsorption performance with a bright future for CO_(2)capture from flue gas after desulfurization.展开更多
Static adsorption and dynamic damage experiments were carried out on typical 8#deep coal rock of the Carboniferous Benxi Formation in the Ordos Basin,NW China,to evaluate the adsorption capacity of hydroxypropyl guar ...Static adsorption and dynamic damage experiments were carried out on typical 8#deep coal rock of the Carboniferous Benxi Formation in the Ordos Basin,NW China,to evaluate the adsorption capacity of hydroxypropyl guar gum and polyacrylamide as fracturing fluid thickeners on deep coal rock surface and the permeability damage caused by adsorption.The adsorption morphology of the thickener was quantitatively characterized by atomic force microscopy,and the main controlling factors of the thickener adsorption were analyzed.Meanwhile,the adsorption mechanism of the thickener was revealed by Zeta potential,Fourier infrared spectroscopy and X-ray photoelectron spectroscopy.The results show that the adsorption capacity of hydroxypropyl guar gum on deep coal surface is 3.86 mg/g,and the permeability of coal rock after adsorption decreases by 35.24%–37.01%.The adsorption capacity of polyacrylamide is 3.29 mg/g,and the permeability of coal rock after adsorption decreases by 14.31%–21.93%.The thickness of the thickener adsorption layer is positively correlated with the mass fraction of thickener and negatively correlated with temperature,and a decrease in pH will reduce the thickness of the hydroxypropyl guar gum adsorption layer and make the distribution frequency of the thickness of polyacrylamide adsorption layer more concentrated.Functional group condensation and intermolecular force are chemical and physical forces for adsorbing fracturing fluid thickener in deep coal rock.Optimization of thickener mass fraction,chemical modification of thickener molecular,oxidative thermal degradation of polymer and addition of desorption agent can reduce the potential damages on micro-nano pores and cracks in coal rock.展开更多
Understanding the factors underlying the interaction of water with oxide surfaces is of high technological importance for applications ranging from nuclear fuel safety to heterogeneous catalysis.However,it is a comple...Understanding the factors underlying the interaction of water with oxide surfaces is of high technological importance for applications ranging from nuclear fuel safety to heterogeneous catalysis.However,it is a complex task as numerous different factors(related to the surface and bulk properties)are involved.In the present study,we investigated the characteristics of water adsorption(quantities adsorbed and energetics)on binary oxides of fluorite structure and their mixed oxide combinations(solid solutions).Three representative oxides were chosen,differing in lattice parameter(ionic radius)and oxidation state:ThO_(2)which has a very stable Th^(4+)cation,CeO_(2)in which the cerium cations can be easily reduced to Ce^(3+),and UO_(2)in which the uranium cations tend to further oxidize to U^(5+)and U^(6+).Based on the H_(2)O adsorption isotherms and enthalpies of adsorption versus coverage,combined with X-ray photoelectron spectroscopy(XPS)study of the oxide surface,the main factors underlying the characteristics of water adsorption on the fluorite oxides were identified.The present work points to the importance of oxygen hyper-stoichiometry(in U-containing oxides)on the interaction of water with the oxide’s surface.Furthermore,correlations between Fermi level positioning and water dissociation tendencies are established.This work advances our understanding of water-oxide interactions with implications for material design in energy and environmental systems.展开更多
Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the m...Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the mechanisms of gas adsorption in MOFs,including physical adsorption,chemisorption,and synergistic effects,which contribute to their efficiency in capturing and separating gases.The applications of MOFs in key areas such as carbon dioxide capture,hydrogen storage,natural gas separation,and air purification are discussed,highlighting their potential to address pressing environmental and energy challenges.Additionally,the use of MOFs in selective gas separation,membranes,and adsorption-based technologies like Pressure Swing Adsorption(PSA)and Vacuum Swing Adsorption(VSA)is explored,emphasizing their advantages over traditional materials.Despite challenges related to scalability,stability,and cost,MOFs hold great promise for advancing gas separation technologies in the near future,offering more efficient,sustainable,and environmentally friendly solutions.展开更多
This study mainly investigates the influence of pore water characteristics on the adsorption properties of coalbed methane through integrated low field nuclear magnetic resonance(LF-NMR),adsorption experiments,and mol...This study mainly investigates the influence of pore water characteristics on the adsorption properties of coalbed methane through integrated low field nuclear magnetic resonance(LF-NMR),adsorption experiments,and molecular dynamics(MD)simulations.Pore water states in three coal ranks were characterized during progressive hydration.Multi-scale analysis revealed how pore water evolution regulates methane adsorption processes.During the diffusion-dominated stage(M2-M3),adsorbed water penetrates into the micropores.In the highly wettable brown coal(L1),the adsorbed water content reaches 2.12 g while in the anthracite(A1),it is only 0.29 g.During the active water injection stage(M4-M6),non-adsorbed water dominates in anthracite(over 85%of the total water content of 4.01 g),while adsorbed water remains dominant in lignite(over 60%of the total water content of 3.52 g).Water content plays a key role in methane adsorption in coal.During the water addition phase,the influence of methane adsorption on medium-to-low-rank coal is relatively weak,while the methane adsorption capacity of high-rank coal A1 shows a significant decrease during both the water diffusion and water addition phases,corresponding to a reduction in Langmuir volume of 21.22 cm^(3)/g.Molecular dynamics(MD)results further show that the free energy between molecules on the surface of hydroxyl-modified coal increases,with hydroxyl groups driving electrostatic interactions between coal and water molecules.Increased steric hindrance inhibits hydrogen bond formation and reduces the rate of hydrogen bond growth.There is a significant correlation between pore water content and coal-water molecular interaction energy,which cross-scale validates the results of LF-NMR testing and MD simulations.展开更多
Increasing attention has been paid to radioactive wastewater to direct discharge in Japan or accidental leaks.Strontium-90(90Sr)and Cobalt-60(^(60)Co)are the most hazardous nuclides in waste discharged form nuclear re...Increasing attention has been paid to radioactive wastewater to direct discharge in Japan or accidental leaks.Strontium-90(90Sr)and Cobalt-60(^(60)Co)are the most hazardous nuclides in waste discharged form nuclear reactors.Because of their high solubility and long half-lives,these radioisotopes can persist for hundreds of years before decaying to negligible levels.Herein,a green and biodegradable material nanoscale zero-valent iron(nZVI)supported by bacterial cellulose particles(BCP-nZVI)is constructed for the first time to adsorb Co^(2+)and Sr^(2+)in single and binary systems.BCP-nZVI shows superior adsorption capacities of Co^(2+)and Sr^(2+)in a single system within a wide range of pH values from 5 to 7,while the coexistence of Co^(2+)adsorption inhibits the Sr^(2+)in binary system.Pseudo-second-order dynamics model and Langmuir isothermal model can be indicated the BCP-nZVI adsorption progress with 107.10 mg/g(Co^(2+))and 64.96 mg/g(Sr^(2+))maximum adsorption capacity.BCP-nZVI has outstanding stability,allowing it to be stored for more than one month with compromising its performance.More importantly,BCP-nZVI exhibits exceptional removal efficiency of Co^(2+)(92.53%)and Sr^(2+)(58.62%)removal in natural seawater systems.The mechanism investigation illustrates the high adsorption capacity of BCP-nZVI for Co^(2+)is controlled by redox and hydroxyl complexation.While Sr^(2+)is controlled by hydroxyl complexed adsorption,thus it has weak against interference by cations like Na^(+),Ca^(2+),etc.BCP-nZVI exhibits the advantages of high adsorption capacity,wide pH range,strong stability,and good applicability in natural seawater,which has excellent potential for application in radioactive ions removal.展开更多
As the fundamental unit of soil,aggregates exhibit significant variations in their abilities to adsorb and desorb trace elements,depending on their size.Batch experiments were conducted to investigate the characterist...As the fundamental unit of soil,aggregates exhibit significant variations in their abilities to adsorb and desorb trace elements,depending on their size.Batch experiments were conducted to investigate the characteristics of adsorption and desorption of cadmium(Cd),copper(Cu),and lead(Pb)on and from soil aggregate fractions from three layers of a calcareous soil profile in Changxing County,Zhejiang Prvince,China.The results showed that both Langmuir and Freundlich models successfully described the isothermal adsorption processes of single Cd,Cu,and Pb on different soil aggregates.Additionally,aggregates from the bottom soil layer showed the highest maximum adsorption capacity and required the lowest energy for Cd,Cu,and Pb adsorption compared to aggregates from upper soil layers.The physicochemical properties of soil aggregates were found to govern the adsorption and desorption processes of heavy metals rather than the aggregate size,wherein the contents of iron/aluminum oxides and organic matter were the most crucial influencing factors.Cadmium displayed higher mobility than Cu and Pb in different soil aggregates,and the maximum adsorption capacities of the metal ions followed the order of Pb>Cu>Cd,while their desorption rates followed the order of Cd>Cu>Pb.Additionally,the<0.053 mm microaggregates presented the lowest desorption rates for Cd,Cu,and Pb compared to other soil aggregate fractions in each soil layer.Furthermore,the orthogonal experiment results demonstrated that the competitive adsorption between metals occurred on soil aggregates in the ternary heavy metal system,but only the desorption of Pb was significantly affected by the coexistence of Cd and Cu.展开更多
An in-depth understanding of the competition mechanism between olefins and different types of sulfides in gasoline is essential to improve the desulfurization selectivity of the adsorption desulfurization process(ADS)...An in-depth understanding of the competition mechanism between olefins and different types of sulfides in gasoline is essential to improve the desulfurization selectivity of the adsorption desulfurization process(ADS).In this study,the competitive adsorption and diffusion mechanism of two systems,diethyl sulfide/cyclohexene and n-butyl mercaptan/cyclohexene,with different adsorption amounts in siliceous faujasite zeolite(FAU) were investigated by Monte Carlo(MC) and molecular dynamics(MD).The systems exhibited a two-stage loading-dependent competitive adsorption and diffusion mechanism,with an inflection point of 32 molecule/UC(moleculers per microcoulomb).Before the inflection point(4-32molecule/UC),the competition mechanism of the two systems was the "optimal-displacement" mechanism.After the inflection point,the mechanism of the diethyl sulfide/cyclohexene changed to "relocation-displacement",while that of the n-butyl mercaptan/cyclohexene system changed to "dominantdisplacement".Compared to ether functional groups,the alcohol functional group has higher polarity and stronger adsorption stability,thus occupying more favorable adsorption sites within the supercages(SCs),while ethyl sulfide shifts outward to other sites within other SCs.In addition,the diffusion performance of adsorbent is related to the adsorption energy.The lower the adsorption energy,the weaker the diffusion ability.Meanwhile,the diffusion performance of adsorbates is better at high temperatures and low adsorption capacity.The effect of temperatu re on the desulfu rization selectivity was determined.A lower temperature is favorable for the adsorption capacity of the two systems and the removal selectivity of sulfides.This study provides fundamental insights into the competitive adsorption and diffusion mechanisms among sulfides,mercaptans and olefins,offering theoretical guidance for adsorbent design and reaction temperature optimization.展开更多
Quantum spin Hall state usually emerges in non-magnetic systems,which are typically incompatible withferromagnetism.Here,we predict that two-dimensional(2D)ferrovalley semiconductor single-layer(SL)2HNbTe_(2)can be tr...Quantum spin Hall state usually emerges in non-magnetic systems,which are typically incompatible withferromagnetism.Here,we predict that two-dimensional(2D)ferrovalley semiconductor single-layer(SL)2HNbTe_(2)can be transformed into a 2D room-temperature quantum spin Hall insulator through hydrogen(H)atom adsorption.The SL 2H-NbTe_(2) is found to possess a giant spontaneous valley polarization of 274 meV,which is much larger than those of most available ferrovalley materials.Upon H atom adsorption,a transitionfrom ferromagnetism to non-magnetism emerges.More interestingly,H-adsorbed NbTe_(2) is predicted to be aquantum spin Hall insulator with a direct band gap of 110meV(equal to a working temperature of 1267 K).The predicted rich quantum effects render the 2H-NbTe_(2) a promising candidate for practical valleytronic andtopological electronics.展开更多
To investigate the process of RE^(3+)anti-adsorption on ion-adsorption type rare earth tailings,the thermodynamics,adsorption kinetics and infrared spectroscopy of these materials were investigated.The results indicat...To investigate the process of RE^(3+)anti-adsorption on ion-adsorption type rare earth tailings,the thermodynamics,adsorption kinetics and infrared spectroscopy of these materials were investigated.The results indicate that the initial reaction rate of anti-adsorption of rare earth tailings is fast,but it reaches a balance in 6 min.The formula 1-2a/3-(1-a)2/3=k_2t(k represents rate constant of the reaction,a represents anti-adsorption rate of rare earth ore,t represents anti-adsorption time)of internal diffusion can be used to predict the kinetics of anti-adsorption in IATRE tailings.BecauseΔH<0,ΔG<0,ΔS>0(ΔH,ΔG,ΔS represent change of enthalpy,Gibbs free energy and entropy,respectively),the anti-adsorption of RE^(3+)on ion-adsorption type RE tailings is a spontaneous physical adsorption process.The effects of ligand exchange and strong chemical bond are not found in this process.Because the anti-adsorption process is exothermic,heating will inhibit the reaction and decrease the anti-adsorption performance.According to the infrared spectrum analysis,there are no significant changes in the mineral surface after anti-adsorption.Based on these findings,the anti-adsorption of rare earth tailings is physical adsorption.展开更多
During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this ...During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this study,the impact of chlorination and UV modification on the physicochemical properties of polystyrene(PS)and polyvinyl chloride(PVC)were investigated,and the adsorption behavior of pefloxacin(PEF)before and after modificationwas examined.The effect of pH,ionic strength,dissolved organicmatter,heavymetal ions and other water environmental conditions on adsorption behavior was revealed.The results showed that PS had a higher adsorption capacity of PEF than PVC,and the modification increased the presence of O-containing functional groups in the MPs,thereby enhancing the adsorption capacity of both materials.Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period,leading to better adsorption performance of chlorination.The optimal pH for adsorption was found to be 6,and NaCl,sodium alginate and Cu2+would inhibit adsorption to varying degrees,among which the inhibition caused by pH was the strongest.Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs.The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding.The study clarified the effects of modification on the physicochemical properties of MPs,providing reference for subsequent biotoxicity analysis and environmental protection studies.展开更多
Current research on heterogeneous advanced oxidation processes(HAOPs)predominantly emphasizes catalyst iteration and innovation.Significant efforts have been made to regulate the electron structure and optimize the el...Current research on heterogeneous advanced oxidation processes(HAOPs)predominantly emphasizes catalyst iteration and innovation.Significant efforts have been made to regulate the electron structure and optimize the electron distribution,thereby increasing the catalytic activity.However,this focus often overshadows an equally essential aspect of HAOPs:the adsorption effect.Adsorption is a critical initiator for triggering the interaction of oxidants and contaminants with heterogeneous catalysts.The efficacy of these interactions is influenced by a variety of physicochemical properties,including surface chemistry and pore sizes,which determine the affinities between contaminants and material surfaces.This dispar ity in affinity is pivotal because it underpins the selective removal of contaminants,especially in complex waste streams containing diverse contaminants and competing matrices.Consequently,understanding and mastering these interfacial interactions is fundamentally indispensable not only for improving pro cess efficiency but also for enhancing the selectivity of contaminant removal.Herein,we highlight the importance of adsorption-driven interfacial interactions for fundamentally elucidating the catalytic mechanisms of HAOPs.Such interactions dictate the overall performance of the treatment processes by balancing the adsorption,reaction,and desorption rates on the catalyst surfaces.Elucidating the adsorption effect not only shifts the paradigm in understanding HAOPs but also improves their practical ity in water treatment and wastewater decontamination.Overall,we propose that revisiting adsorption driven interfacial interactions holds great promise for optimizing catalytic processes to develop effective HAOP strategies.展开更多
In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprec...In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid(SA)as a morphological control agent.Doping the LDH crystals with carboxylate ions(RCOO−)derived from SA caused the crystals to develop in a radial direction.This changed the pore characteristics and increased the density of active surface sites.Subsequently,SA/MgFe-LDH showed excellent affinity for As(III)and As(V)with maximum sorption densities of 2.42 and 1.60 mmol/g,respectively.By comparison,the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III)and As(V),respectively.The LDH was effective over a wide pH range for As(III)adsorption(pH 3-8.5)and As(V)adsorption(pH 3-6.5).Using a combination of spectroscopy and sorption modeling calculations,the main sorption mechanism of As(III)and As(V)on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchangewith hydroxyl group(-OH)and RCOO−.Specifically,bidentate As-Fe complexeswere proposed for both As(III)and As(V)uptake,with the magnitude of formation varying with the initial As concentration.Importantly,the As-laden adsorbent had satisfactory stability in simulated real landfill leachate.These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.展开更多
基金supported by the Open Project Funding of Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes,Ministry of Education,Hubei University of Technology(No.HGKFZ03).
文摘In this study,chitosan(CS)was combined with microcrystalline cellulose(MCC)to fabricate composite hydrogel beads.These beads were further modified through blending and grafting with polyethyleneimine(PEI)to develop chitosan/microcrystalline cellulose@polyethyleneimine(CS/MCC@PEI)composite gel spheres for the efficient adsorption of diclofenac sodium(DS)from aqueous solutions.The adsorbent was characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),X-ray pho-toelectron spectroscopy(XPS),and thermogravimetric analysis(TGA).The CS/MCC@PEI composite exhibited a spherical morphology with a porous structure,abundant surface functional groups,and a high adsorption capac-ity of 274.84 mg/g for DS.Kinetic studies revealed that the adsorption process followed the pseudo-second-order model,dominated by physical adsorption,with both surface and internal diffusion influencing the adsorption rate.The Freundlich isotherm model best described the adsorption behavior,indicating multilayer adsorption on heterogeneous surfaces.Environmental adaptability tests demonstrated minimal interference from co-existing anions and humic acid,while regeneration experiments confirmed excellent reusability(>77%removal after five cycles).The adsorption mechanism involved electrostatic interactions and hydrogen bonding between the hydroxyl/amino groups of the composite and DS.These findings highlight the potential of CS/MCC@PEI as a cost-effective and sustainable adsorbent for DS removal from water.
基金the support from the National Key Research and Development Program of China (No. 2022YFC2904504)the Science and Technology Research Project of Jiangxi Provincial Department of Education, China (No. GJJ2200864)the Gansu Provincial Key Research and Development Project, China (No. 22YF7GA073)。
文摘The flotation separation of argentite from sphalerite using ammonium dibutyl dithiophosphate(ADD)was studied.Molecular simulation(MS)calculation shows that ADD is chemisorbed on argentite and sphalerite surface in the form of S—P bond.The ADD adsorption on argentite and sphalerite surface in Ag^(+)system was revealed by ICP,Zeta potential and XPS analyses.It is shown that the dissolved Ag^(+)from argentite surface can be absorbed on sphalerite surface in the form of silver hydroxide,and AgOH hydrophilic colloid prevents the adsorption of ADD on sphalerite surface.The ADD adsorption on argentite and sphalerite surface in the pulp containing silver and zinc ions was revealed by adsorption capacity and surface wettability analyses.It is shown that the combined Zn(OH)_(2) and AgOH hydrophilic colloid leads to greater ADD adsorption capacity on argentite surface and stronger surface hydrophobicity than sphalerite.Flotation tests demonstrate that ADD enables efficient separation of argentite from sphalerite in the pulp containing silver and zinc ions.
基金the Department of Science and Technology(DST),Govt.of India for providing funds under the FIST program and PURSE grant vide No.SR/PURSE/2020/31 to the department of Chemistry,University of Kashmir.
文摘This study presents a thorough investigation into the use of single and twin-tailed cationic and anionic surfactant-modified chitosan(SMCS)hydrogel beads as effective adsorbents for the elimination of hazardous polycyclic aromatic hydrocarbons(PAHs)from aqueous solutions.The Chitosan(CS)hydrogel beads were modified with single/twin-tailed anionic surfactants,sodium dodecyl sulfate(SDS)and sodium bis(2-ethylhexyl)sulfosuccinate(AOT),and cationic surfactants,dodecyltrimethylammonium bromide(DTAB)and didodecyldimethylammonium bromide(DDAB),to enhance their adsorption capacity of PAHs.The CS and SMCS beads were evaluated for their structural,mechanical,and adsorption properties using a range of techniques,including infrared spectroscopy(IR),energy-dispersive X-ray spectroscopy(EDX),rheometry,and field emission scanning electron microscopy(FESEM).Adsorption experiments of naphthalene(Nap),acenaphthene(Ace),and phenanthrene(Phe)on SMCS beads demonstrate that they have significantly higher adsorption capacities than CS beads,due to increase in hydrophobic interactions.Adsorption capacity followed the trend,Phen>Ace>Nap for all the beads revealing that twin-tailed SMCS bead possess much higher adsorption capacities(Qmax)compared to single-tailed SMCS beads.For twin tailed surfactants,the maximum adsorption capacities for Nap,Ace and Phe varied as CS-AOT(CS-DDAB):430.0(323.8)611.60(538.18)633.39(536.99)mg/g respectively,outperforming other reported hydrogel beads.The study highlights the simplicity,eco-friendliness,and enhanced performance of surfactant modification for developing high-efficiency adsorbents,paving the way for cost-effective solutions in water re-mediation.
基金supported by the National Natural Science Foundation of China(No.52370112).
文摘In order to address the evolving emission characteristics of oxygenated volatile organic compounds(OVOCs),it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with large kinetic diameters.In this study,we used co-pyrolysis to prepare a series of graded porous carbon materials with well-developed micropores by adjusting the doping ratios of root nodules and pretreated cellulose.The material with root nodule to cellulose mass ratio of 1:1(TCC-RN-1)exhibited the highest saturated adsorption capacity for butyl acetate(834 mg/g).This can be attributed to enhanced pore size distribution from nodule doping,which facilitates the development of a micropore-graded structure.Additionally,the nodules acted as auxiliary activating agents that enhanced the KOH micropore regulation effect during the activation stage,resulting in the highest micropore volume(0.863 cm^(3)/g).The doping of root nodules facilitated the formation of additional defects on the surface of the porous carbon material,leading to a more disordered arrangement that improved pollutant adsorption.Furthermore,TCC-RN-1 demonstrated good thermal stability in an air atmosphere,main-taining a butyl acetate adsorption capacity exceeding 95%after five adsorption-desorption cycles.This indicates its favorable potential for industrial applications.
基金supported by the National Key R&D Program of China(No.2021YFB3501102).
文摘Porous carbon microspheres are widely regarded as a superior CO_(2) adsorbent due to their exceptional efficiency and affordability.However,better adsorption performance is very attractive for porous carbon microspheres.And modification of the pore structure is one of the effective strategies.In this study,multi-cavity mesoporous carbon microspheres were successfully synthesized by the synergistic method of soft and hard templates,during which a phenolic resin with superior thermal stability was employed as the carbon precursor and a mixture of silica sol and F108 as the mesoporous template.Carbon microspheres with multi-cavity mesoporous structures were prepared,and all the samples showed highly even mesopores,with diameters around 12 nm.The diameter of these microspheres decreased from 396.8 nm to about 182.5 nm with the increase of silica sol.After CO_(2) activation,these novel carbon microspheres(APCF0.5-S1.75)demonstrated high specific surface area(983.3 m^(2)/g)and remarkable CO_(2) uptake of 4.93 mmol/g at 0℃ and1 bar.This could be attributed to the unique multi-cavity structure,which offers uniform mesoporous pore channels,minimal CO_(2) transport of and a greater number of active sites for CO_(2) adsorption.
基金supported by the National Natural Science Foundation of China(22175136)the State Key Laboratory of Electrical Insulation and Power Equipment(EIPE23127)the Fundamental Research Funds for the Central Universities(xtr052024009).
文摘Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation.However,the requirement of highly pure H_(2)for re-hydrogenation limits its wide application.Here,amorphous Al_(2)O_(3)shells(10 nm)were deposited on the surface of highly active hydrogen storage material particles(MgH_(2)-ZrTi)by atomic layer deposition to obtain MgH_(2)-ZrTi@Al_(2)O_(3),which have been demonstrated to be air stable with selective adsorption of H_(2)under a hydrogen atmosphere with different impurities(CH_(4),O_(2),N_(2),and CO_(2)).About 4.79 wt%H_(2)was adsorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)at 75℃under 10%CH_(4)+90%H_(2)atmosphere within 3 h with no kinetic or density decay after 5 cycles(~100%capacity retention).Furthermore,about 4 wt%of H_(2)was absorbed by MgH_(2)-ZrTi@10nmAl_(2)O_(3)under 0.1%O_(2)+0.4%N_(2)+99.5%H_(2)and 0.1%CO_(2)+0.4%N_(2)+99.5%H_(2)atmospheres at 100℃within 0.5 h,respectively,demonstrating the selective hydrogen absorption of MgH_(2)-ZrTi@10nmAl_(2)O_(3)in both oxygen-containing and carbon dioxide-containing atmospheres hydrogen atmosphere.The absorption and desorption curves of MgH_(2)-ZrTi@10nmAl_(2)O_(3)with and without absorption in pure hydrogen and then in 21%O_(2)+79%N_(2)for 1 h were found to overlap,further confirming the successful shielding effect of Al_(2)O_(3)shells against O_(2)and N_(2).The MgH_(2)-ZrTi@10nmAl_(2)O_(3)has been demonstrated to be air stable and have excellent selective hydrogen absorption performance under the atmosphere with CH_(4),O_(2),N_(2),and CO_(2).
基金financial support from the National Natural Science Foundation of China(52203123)the Sichuan Science and Technology Program(2023NSFSC0991)+2 种基金the State Key Laboratory of Polymer Materials Engineering(sklpme 2023-1-05 and sklpme 2024-2-04)the Fundamental Research Funds for the Central Universitiespartially sponsored by the Double First-Class Construction Funds of Sichuan University。
文摘Solvation structures fundamentally control the ion-transport dynamics and mechanical properties of polymer electrolytes.However,there is a lack of strategies to rationally regulate the solvation structures and fundamental understanding on how they control the electrochemical performances.Herein,by harnessing the electrostatic adsorption of one-dimensional nanofiller(i.e.,surface-charged halloysite nanotubes,d-HNTs),we successfully fabricate a high-performance polymer nanocomposite electrolyte enabled by strong surface adsorption,referred as adsorption-state polymer electrolyte(ASPE).This ASPE shows fast ion transport(0.71±0.05 mS cm^(-1)at room temperature),high mechanical strength and toughness(10.3±0.05 MPa;15.73 MJ m^(-3)),improved lithium-ion transference number,and long cycle life with lithium metal anode,in comparison with the sample without the d-HNT adsorption effect.To fundamentally understand these high performances,an anion-rich asymmetric solvent structure model is further proposed and evidenced by both experiments and simulation studies.Results show that the electrostatic adsorption among the d-HNT,ionic liquid electrolyte,and polymer chain generates a nano filler-supported fast ion-conduction pathway with asymmetric Li+-coordination microenvironment.Meanwhile,the anion-rich asymmetric solvent structure model of ASPE also generates a fast de-solvation and anion-derived stable solid-electrolyte interphase for lithium metal anode.The high performance and understanding of the mechanism for ASPE provide a promising path to develop advanced polymer electrolytes.
基金National Natural Science Foundation of China(51966002)Natural Science Foundation of Guangxi Province(2020GXNSFAA159144)。
文摘Adsorption by solid amine adsorbent is a promising technology for decarbonization of flue gas.However,adsorption properties of many solid amine adsorbents need to be enhanced,and it is necessary to further study the CO_(2)adsorption mechanism.A novel CO_(2)adsorbent with high capacity was obtained by grafting 3-aminopropyltriethoxysilane(APTES)on a micro-mesoporous composite molecular sieve ZSM-5/MCM-48 as the support,and then impregnated with tetraethylenepentamine(TEPA)or polyethyleneimine(PEI).The maximum adsorption capacity of APTES-ZSM-5/MCM-48-TEPA-60(A-ZM-T60),loaded with 60%(in mass)TEPA,for CO_(2)reaches 5.82 mmol·g^(-1) at 60℃in 15%(in volume)CO_(2).Carbamate,alkyl ammonium carbamate and carbonate are generated during the chemical adsorption,which is dominant for CO_(2)adsorption because of the reaction between CO_(2)and amino groups on the adsorbent,simultaneously accompanied by weak physical adsorption.All above data confirm that these composites display an outstanding adsorption performance with a bright future for CO_(2)capture from flue gas after desulfurization.
基金Supported by National Natural Science Foundation of China(51674209)Sichuan Province Youth Science and Technology Innovation Team(2021JDTD0017).
文摘Static adsorption and dynamic damage experiments were carried out on typical 8#deep coal rock of the Carboniferous Benxi Formation in the Ordos Basin,NW China,to evaluate the adsorption capacity of hydroxypropyl guar gum and polyacrylamide as fracturing fluid thickeners on deep coal rock surface and the permeability damage caused by adsorption.The adsorption morphology of the thickener was quantitatively characterized by atomic force microscopy,and the main controlling factors of the thickener adsorption were analyzed.Meanwhile,the adsorption mechanism of the thickener was revealed by Zeta potential,Fourier infrared spectroscopy and X-ray photoelectron spectroscopy.The results show that the adsorption capacity of hydroxypropyl guar gum on deep coal surface is 3.86 mg/g,and the permeability of coal rock after adsorption decreases by 35.24%–37.01%.The adsorption capacity of polyacrylamide is 3.29 mg/g,and the permeability of coal rock after adsorption decreases by 14.31%–21.93%.The thickness of the thickener adsorption layer is positively correlated with the mass fraction of thickener and negatively correlated with temperature,and a decrease in pH will reduce the thickness of the hydroxypropyl guar gum adsorption layer and make the distribution frequency of the thickness of polyacrylamide adsorption layer more concentrated.Functional group condensation and intermolecular force are chemical and physical forces for adsorbing fracturing fluid thickener in deep coal rock.Optimization of thickener mass fraction,chemical modification of thickener molecular,oxidative thermal degradation of polymer and addition of desorption agent can reduce the potential damages on micro-nano pores and cracks in coal rock.
基金Open access funding provided by Ben-Gurion University
文摘Understanding the factors underlying the interaction of water with oxide surfaces is of high technological importance for applications ranging from nuclear fuel safety to heterogeneous catalysis.However,it is a complex task as numerous different factors(related to the surface and bulk properties)are involved.In the present study,we investigated the characteristics of water adsorption(quantities adsorbed and energetics)on binary oxides of fluorite structure and their mixed oxide combinations(solid solutions).Three representative oxides were chosen,differing in lattice parameter(ionic radius)and oxidation state:ThO_(2)which has a very stable Th^(4+)cation,CeO_(2)in which the cerium cations can be easily reduced to Ce^(3+),and UO_(2)in which the uranium cations tend to further oxidize to U^(5+)and U^(6+).Based on the H_(2)O adsorption isotherms and enthalpies of adsorption versus coverage,combined with X-ray photoelectron spectroscopy(XPS)study of the oxide surface,the main factors underlying the characteristics of water adsorption on the fluorite oxides were identified.The present work points to the importance of oxygen hyper-stoichiometry(in U-containing oxides)on the interaction of water with the oxide’s surface.Furthermore,correlations between Fermi level positioning and water dissociation tendencies are established.This work advances our understanding of water-oxide interactions with implications for material design in energy and environmental systems.
文摘Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the mechanisms of gas adsorption in MOFs,including physical adsorption,chemisorption,and synergistic effects,which contribute to their efficiency in capturing and separating gases.The applications of MOFs in key areas such as carbon dioxide capture,hydrogen storage,natural gas separation,and air purification are discussed,highlighting their potential to address pressing environmental and energy challenges.Additionally,the use of MOFs in selective gas separation,membranes,and adsorption-based technologies like Pressure Swing Adsorption(PSA)and Vacuum Swing Adsorption(VSA)is explored,emphasizing their advantages over traditional materials.Despite challenges related to scalability,stability,and cost,MOFs hold great promise for advancing gas separation technologies in the near future,offering more efficient,sustainable,and environmentally friendly solutions.
基金supported by the National Science Fund for Distinguished Young Scholars(No.51925404)the National Natural Science Foundation of China(Nos.52104233,52104228 and 52404261)the Fundamental Research Funds for the Central Universities(No.2023ZDPY05).
文摘This study mainly investigates the influence of pore water characteristics on the adsorption properties of coalbed methane through integrated low field nuclear magnetic resonance(LF-NMR),adsorption experiments,and molecular dynamics(MD)simulations.Pore water states in three coal ranks were characterized during progressive hydration.Multi-scale analysis revealed how pore water evolution regulates methane adsorption processes.During the diffusion-dominated stage(M2-M3),adsorbed water penetrates into the micropores.In the highly wettable brown coal(L1),the adsorbed water content reaches 2.12 g while in the anthracite(A1),it is only 0.29 g.During the active water injection stage(M4-M6),non-adsorbed water dominates in anthracite(over 85%of the total water content of 4.01 g),while adsorbed water remains dominant in lignite(over 60%of the total water content of 3.52 g).Water content plays a key role in methane adsorption in coal.During the water addition phase,the influence of methane adsorption on medium-to-low-rank coal is relatively weak,while the methane adsorption capacity of high-rank coal A1 shows a significant decrease during both the water diffusion and water addition phases,corresponding to a reduction in Langmuir volume of 21.22 cm^(3)/g.Molecular dynamics(MD)results further show that the free energy between molecules on the surface of hydroxyl-modified coal increases,with hydroxyl groups driving electrostatic interactions between coal and water molecules.Increased steric hindrance inhibits hydrogen bond formation and reduces the rate of hydrogen bond growth.There is a significant correlation between pore water content and coal-water molecular interaction energy,which cross-scale validates the results of LF-NMR testing and MD simulations.
基金supported by the National Natural Science Foundation of China(Nos.51778618 and 52070192)the State Key Laboratory of Materials-Oriented Chemical Engineering(No.SKL-MCE-23B09)the open fund of Information Materials and Intelligent Sensing Laboratory of Anhui Province(No.IMIS202213).
文摘Increasing attention has been paid to radioactive wastewater to direct discharge in Japan or accidental leaks.Strontium-90(90Sr)and Cobalt-60(^(60)Co)are the most hazardous nuclides in waste discharged form nuclear reactors.Because of their high solubility and long half-lives,these radioisotopes can persist for hundreds of years before decaying to negligible levels.Herein,a green and biodegradable material nanoscale zero-valent iron(nZVI)supported by bacterial cellulose particles(BCP-nZVI)is constructed for the first time to adsorb Co^(2+)and Sr^(2+)in single and binary systems.BCP-nZVI shows superior adsorption capacities of Co^(2+)and Sr^(2+)in a single system within a wide range of pH values from 5 to 7,while the coexistence of Co^(2+)adsorption inhibits the Sr^(2+)in binary system.Pseudo-second-order dynamics model and Langmuir isothermal model can be indicated the BCP-nZVI adsorption progress with 107.10 mg/g(Co^(2+))and 64.96 mg/g(Sr^(2+))maximum adsorption capacity.BCP-nZVI has outstanding stability,allowing it to be stored for more than one month with compromising its performance.More importantly,BCP-nZVI exhibits exceptional removal efficiency of Co^(2+)(92.53%)and Sr^(2+)(58.62%)removal in natural seawater systems.The mechanism investigation illustrates the high adsorption capacity of BCP-nZVI for Co^(2+)is controlled by redox and hydroxyl complexation.While Sr^(2+)is controlled by hydroxyl complexed adsorption,thus it has weak against interference by cations like Na^(+),Ca^(2+),etc.BCP-nZVI exhibits the advantages of high adsorption capacity,wide pH range,strong stability,and good applicability in natural seawater,which has excellent potential for application in radioactive ions removal.
基金financially supported by the National Key Research and Development Program of China(No.2017YFD0800305)。
文摘As the fundamental unit of soil,aggregates exhibit significant variations in their abilities to adsorb and desorb trace elements,depending on their size.Batch experiments were conducted to investigate the characteristics of adsorption and desorption of cadmium(Cd),copper(Cu),and lead(Pb)on and from soil aggregate fractions from three layers of a calcareous soil profile in Changxing County,Zhejiang Prvince,China.The results showed that both Langmuir and Freundlich models successfully described the isothermal adsorption processes of single Cd,Cu,and Pb on different soil aggregates.Additionally,aggregates from the bottom soil layer showed the highest maximum adsorption capacity and required the lowest energy for Cd,Cu,and Pb adsorption compared to aggregates from upper soil layers.The physicochemical properties of soil aggregates were found to govern the adsorption and desorption processes of heavy metals rather than the aggregate size,wherein the contents of iron/aluminum oxides and organic matter were the most crucial influencing factors.Cadmium displayed higher mobility than Cu and Pb in different soil aggregates,and the maximum adsorption capacities of the metal ions followed the order of Pb>Cu>Cd,while their desorption rates followed the order of Cd>Cu>Pb.Additionally,the<0.053 mm microaggregates presented the lowest desorption rates for Cd,Cu,and Pb compared to other soil aggregate fractions in each soil layer.Furthermore,the orthogonal experiment results demonstrated that the competitive adsorption between metals occurred on soil aggregates in the ternary heavy metal system,but only the desorption of Pb was significantly affected by the coexistence of Cd and Cu.
基金support from the National Natural Science Foundation of China (22325808,U22B20140,22021004)。
文摘An in-depth understanding of the competition mechanism between olefins and different types of sulfides in gasoline is essential to improve the desulfurization selectivity of the adsorption desulfurization process(ADS).In this study,the competitive adsorption and diffusion mechanism of two systems,diethyl sulfide/cyclohexene and n-butyl mercaptan/cyclohexene,with different adsorption amounts in siliceous faujasite zeolite(FAU) were investigated by Monte Carlo(MC) and molecular dynamics(MD).The systems exhibited a two-stage loading-dependent competitive adsorption and diffusion mechanism,with an inflection point of 32 molecule/UC(moleculers per microcoulomb).Before the inflection point(4-32molecule/UC),the competition mechanism of the two systems was the "optimal-displacement" mechanism.After the inflection point,the mechanism of the diethyl sulfide/cyclohexene changed to "relocation-displacement",while that of the n-butyl mercaptan/cyclohexene system changed to "dominantdisplacement".Compared to ether functional groups,the alcohol functional group has higher polarity and stronger adsorption stability,thus occupying more favorable adsorption sites within the supercages(SCs),while ethyl sulfide shifts outward to other sites within other SCs.In addition,the diffusion performance of adsorbent is related to the adsorption energy.The lower the adsorption energy,the weaker the diffusion ability.Meanwhile,the diffusion performance of adsorbates is better at high temperatures and low adsorption capacity.The effect of temperatu re on the desulfu rization selectivity was determined.A lower temperature is favorable for the adsorption capacity of the two systems and the removal selectivity of sulfides.This study provides fundamental insights into the competitive adsorption and diffusion mechanisms among sulfides,mercaptans and olefins,offering theoretical guidance for adsorbent design and reaction temperature optimization.
基金supported by the National Natural Science Foundation of China(Grant No.11874092)the Fok Ying Tong Education Foundation,China(Grant No.161005)+2 种基金the Science Fund for Distinguished Young Scholars of Hunan Province(Grant No.2021JJ10039)the Planned Science and Technology Project of Hunan Province(Grant No.2017RS3034)the Postgraduate Scientific Research Innovation Project of Hunan Province(Grant No.CX20240080)。
文摘Quantum spin Hall state usually emerges in non-magnetic systems,which are typically incompatible withferromagnetism.Here,we predict that two-dimensional(2D)ferrovalley semiconductor single-layer(SL)2HNbTe_(2)can be transformed into a 2D room-temperature quantum spin Hall insulator through hydrogen(H)atom adsorption.The SL 2H-NbTe_(2) is found to possess a giant spontaneous valley polarization of 274 meV,which is much larger than those of most available ferrovalley materials.Upon H atom adsorption,a transitionfrom ferromagnetism to non-magnetism emerges.More interestingly,H-adsorbed NbTe_(2) is predicted to be aquantum spin Hall insulator with a direct band gap of 110meV(equal to a working temperature of 1267 K).The predicted rich quantum effects render the 2H-NbTe_(2) a promising candidate for practical valleytronic andtopological electronics.
基金financially supported by the National Natural Science Foundation of China(No.41662004)。
文摘To investigate the process of RE^(3+)anti-adsorption on ion-adsorption type rare earth tailings,the thermodynamics,adsorption kinetics and infrared spectroscopy of these materials were investigated.The results indicate that the initial reaction rate of anti-adsorption of rare earth tailings is fast,but it reaches a balance in 6 min.The formula 1-2a/3-(1-a)2/3=k_2t(k represents rate constant of the reaction,a represents anti-adsorption rate of rare earth ore,t represents anti-adsorption time)of internal diffusion can be used to predict the kinetics of anti-adsorption in IATRE tailings.BecauseΔH<0,ΔG<0,ΔS>0(ΔH,ΔG,ΔS represent change of enthalpy,Gibbs free energy and entropy,respectively),the anti-adsorption of RE^(3+)on ion-adsorption type RE tailings is a spontaneous physical adsorption process.The effects of ligand exchange and strong chemical bond are not found in this process.Because the anti-adsorption process is exothermic,heating will inhibit the reaction and decrease the anti-adsorption performance.According to the infrared spectrum analysis,there are no significant changes in the mineral surface after anti-adsorption.Based on these findings,the anti-adsorption of rare earth tailings is physical adsorption.
基金supported by the Shanxi Scholarship Council of China(No.2023-054)the Applied Basic Research Project of Shanxi Province,China(No.20210302123121)the National Natural Science Foundation of China(No.52170045).
文摘During thewater treatment process,chlorination and ultraviolet(UV)sterilization can modify microplastics(MPs)and alter their physicochemical properties,causing various changes between MPs and other pollutants.In this study,the impact of chlorination and UV modification on the physicochemical properties of polystyrene(PS)and polyvinyl chloride(PVC)were investigated,and the adsorption behavior of pefloxacin(PEF)before and after modificationwas examined.The effect of pH,ionic strength,dissolved organicmatter,heavymetal ions and other water environmental conditions on adsorption behavior was revealed.The results showed that PS had a higher adsorption capacity of PEF than PVC,and the modification increased the presence of O-containing functional groups in the MPs,thereby enhancing the adsorption capacity of both materials.Chlorination had a more significant impact on the physicochemical properties of MPs compared to UV irradiation within the same time period,leading to better adsorption performance of chlorination.The optimal pH for adsorption was found to be 6,and NaCl,sodium alginate and Cu2+would inhibit adsorption to varying degrees,among which the inhibition caused by pH was the strongest.Chlorination and UV modification would weaken the inhibitory effect of environmental factors on the adsorption of PEF by MPs.The main mechanisms of adsorption involved electrostatic interaction and hydrogen bonding.The study clarified the effects of modification on the physicochemical properties of MPs,providing reference for subsequent biotoxicity analysis and environmental protection studies.
基金supported by the National Key Research and Development Program of China(2022YFC3205300)the National Natural Science Foundation of China(22176124).
文摘Current research on heterogeneous advanced oxidation processes(HAOPs)predominantly emphasizes catalyst iteration and innovation.Significant efforts have been made to regulate the electron structure and optimize the electron distribution,thereby increasing the catalytic activity.However,this focus often overshadows an equally essential aspect of HAOPs:the adsorption effect.Adsorption is a critical initiator for triggering the interaction of oxidants and contaminants with heterogeneous catalysts.The efficacy of these interactions is influenced by a variety of physicochemical properties,including surface chemistry and pore sizes,which determine the affinities between contaminants and material surfaces.This dispar ity in affinity is pivotal because it underpins the selective removal of contaminants,especially in complex waste streams containing diverse contaminants and competing matrices.Consequently,understanding and mastering these interfacial interactions is fundamentally indispensable not only for improving pro cess efficiency but also for enhancing the selectivity of contaminant removal.Herein,we highlight the importance of adsorption-driven interfacial interactions for fundamentally elucidating the catalytic mechanisms of HAOPs.Such interactions dictate the overall performance of the treatment processes by balancing the adsorption,reaction,and desorption rates on the catalyst surfaces.Elucidating the adsorption effect not only shifts the paradigm in understanding HAOPs but also improves their practical ity in water treatment and wastewater decontamination.Overall,we propose that revisiting adsorption driven interfacial interactions holds great promise for optimizing catalytic processes to develop effective HAOP strategies.
文摘In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid(SA)as a morphological control agent.Doping the LDH crystals with carboxylate ions(RCOO−)derived from SA caused the crystals to develop in a radial direction.This changed the pore characteristics and increased the density of active surface sites.Subsequently,SA/MgFe-LDH showed excellent affinity for As(III)and As(V)with maximum sorption densities of 2.42 and 1.60 mmol/g,respectively.By comparison,the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III)and As(V),respectively.The LDH was effective over a wide pH range for As(III)adsorption(pH 3-8.5)and As(V)adsorption(pH 3-6.5).Using a combination of spectroscopy and sorption modeling calculations,the main sorption mechanism of As(III)and As(V)on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchangewith hydroxyl group(-OH)and RCOO−.Specifically,bidentate As-Fe complexeswere proposed for both As(III)and As(V)uptake,with the magnitude of formation varying with the initial As concentration.Importantly,the As-laden adsorbent had satisfactory stability in simulated real landfill leachate.These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.
