In this work,the structure,viscosity and ion-exchange process of Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) glasses with different Al_(2)O_(3)/SiO_(2) molar ratios were investigated.The results showed that,with increasing Al_(2)...In this work,the structure,viscosity and ion-exchange process of Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) glasses with different Al_(2)O_(3)/SiO_(2) molar ratios were investigated.The results showed that,with increasing Al_(2)O_(3)/SiO_(2) ratio,the simple structural units Q_(1) and Q_(2) transformed into highly aggregated structural units Q_(3) and Q_(4),indicating the increase of polymerization degree of glass network.Meanwhile,the coefficient of thermal expansion decreased from 9.23×10^(-6)℃^(-1) to 8.88×10^(-6)℃^(-1).The characteristic temperatures such as melting,forming,softening and glass transition temperatures increased with the increase of Al_(2)O_(3)/SiO_(2) ratio,while the glasses working temperature range became narrow.The increasing Al_(2)O_(3)/SiO_(2) ratio and prolonging ion-exchange time enhanced the surface compressive stress(CS)and depth of stress layer(DOL).However,the increase of ion exchange temperature increased the DOL and decreased the CS affected by stress relaxation.There was a good linear relationship between stress relaxation and surface compressive stress.Chemical strengthening significantly improved the hardness of glasses,which reached the maximum value of(622.1±10)MPa for sample with Al_(2)O_(3)/SiO_(2) ratio of 0.27 after heat treated at 410℃for 2 h.展开更多
The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first ti...The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first time we investigated the state-selective single electron capture processes for S^(q+)–He and H_(2)(q=11–15)collision systems at an impact energy of q×20 keV and obtained the relative state-selective cross sections.The results indicate that only a few principal quantum states of the projectile energy level are populated in a single electron capture process.In particular,the increase of the projectile charge state leads to the population of the states with higher principal quantum numbers.It is also shown that the experimental averaged n-shell populations are reproduced well by the over-barrier model.The database is openly available in Science Data Bank at 10.57760/sciencedb.j00113.00091.展开更多
Ce (Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol...Ce (Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol·L^-1) and temperature (278 ~318 K) on Ce( Ⅳ ) sorption efficiency was investigated. Sorption increased with increasing nitric acid concentration, indicating that [Ce(NO3)6]^2- complex is the main adsorbed Ce(Ⅳ) species. Oxidation of sorbents by adsorbed Ce ( Ⅳ ) species resulting in Ce ( Ⅲ ) release to the solution was observed. Pyridine based anion exchangers exhibited higher oxidation stability compared to the commercial strong base anion exchanger. Ce( Ⅳ ) reduction was temperature dependent and obeyed pseudo-first-order reaction kinetics. Column separation of Ce ( Ⅳ ) from La ( Ⅲ ) and Y ( Ⅲ ) was carried out from 6 mol·L^-1 nitric acid with PVP based anion exchanger. Reasonable Ce (Ⅳ) breakthrough capacity (0.7 mol·kg^-1 PVP) was achieved. No remarkable decrease of capacity was observed within 3 consequent runs. In contrast, Ce (Ⅲ) leakage due to reduction decreased and breakthrough capacity slightly increased. This effect was more pronounced with increasing temperature. Regeneration with 0.1 mol·L^- 1 nitric acid was successful (recovery 100% ± 4% ) and Ce solution of high purity ( 〉 99.97% ) with respect to La and Y content was gained.展开更多
There are numerous impurities in wet-process phosphoric acid,among which manganese is one of detrimental metallic impurities,and it causes striking negative effects on the industrial phosphoric acid production and dow...There are numerous impurities in wet-process phosphoric acid,among which manganese is one of detrimental metallic impurities,and it causes striking negative effects on the industrial phosphoric acid production and downstream commodity.This article investigated the adsorption behavior of manganese from phosphoric acid employing Sinco-430 cationic ion-exchange resin.Resorting FT-IR and XPS characterizations,the adsorption mechanism was proved to be that manganese was combined with sulfonic acid group.Several crucial parameters such as temperature,phosphoric acid content and resin dose were studied to optimize adsorption efficiency.Through optimization,removal percentage and sorption capacity of manganese reached 53.12 wt%,28.34 mg·g^-1,respectively.Pseudo-2nd-order kinetic model simulated kinetics data best and the activation energy was evaluated as 6.34 kJ·mol^-1 for the sorption reaction of manganese.In addition,the global adsorption rate was first controlled by film diffusion process and second determined by pore diffusion process.It was found that the resin could adsorb up to 50.24 mg·g^-1 for manganese.Equilibrium studies showed that Toth adsorption isotherm model fitted best,followed by Temkin and Langmuir adsorption isotherm models.Thermodynamic analysis showed that manganese adsorption was an endothermic process with enhanced randomness and spontaneity.展开更多
In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption...In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption and chromatographic behavior. It was found that the resin with an ionic capacity of 630 mmol·L^-1(FF-PEI-CR630)possessed high adsorption performance towards lysozyme at 0–100 mmol·L^-1 Na Cl. Therefore, in this work,FF-PEI-CR630 was selected to study the influences of pH and ionic strength(IS) on protein adsorption and chromatographic behavior towards lysozyme. The increase of lysozyme adsorption capacity in the pH range of 6 to 10 was observed. However, the uptake rate decreased in the pH range of 6 to 8 and then remained essentially unchanged from pH 8 to pH 10. Increasing IS led to decreased protein adsorption capacity and increased uptake rate in different pH ranges. Besides, FF-PEI-CR630 maintained dynamic binding capacity as high as over150 mg·ml^-1 at pH 8–10 without NaCl. The research has thus provided insight into the selection of proper pH and IS conditions for protein purification by using FF-PEI-CR630.展开更多
Our previous studies on bovine serum albumin(BSA) adsorption to diethylaminoethyl dextran(DEAE dextran,DexD, grafting-ligand) and DEAE(D, surface-ligand) modified Sepharose FF resins found that all the grafted resins(...Our previous studies on bovine serum albumin(BSA) adsorption to diethylaminoethyl dextran(DEAE dextran,DexD, grafting-ligand) and DEAE(D, surface-ligand) modified Sepharose FF resins found that all the grafted resins(FF-DexD and FF-D-DexD) exhibited extremely fast uptake rate(effective diffusivity, D_e, D_e/D_O> 1.4),which was six times greater than the ungrafted resins(D_e/D_O < 0.3). In this work, the influence of ionic strength(IS) on 6 typical DEAE dextran-grafted resins was investigated. Bath adsorption equilibria and kinetics, breakthrough, and linear gradient elution experiments were conducted. Commercial DEAE Sepharose FF was used for comparison. It is found that protein adsorption capacities on DEAE dextran-FF resins and the commercial resin decreased with increasing IS, but DEAE dextran-FF resins exhibited much higher capacity sensitivity to salt concentration. Besides, steeper decrease of adsorption capacities could be obtained at higher graftingligand or surface-ligand density. It is worth noting that the facilitating role of surface-ligand to the "chain delivery" effect was weakened after adding salt, leading to the less improvement in uptake rate by increasing surface-ligand density at higher IS. Although the uptake rates of the DEAE dextran-FF resins increased first and then decreased with increasing IS, they kept the extremely high level of De values(D_e/D_O > 1.1) at the their working/binding IS range. Moreover, the DEAE dextran-FF resin displayed much higher adsorption capacities and De values than commercial ungrafted resin in their working condition. Furthermore, the column results of DEAE dextran-FF resins presented higher dynamic binding capacities than and similar elution ISs with DEAE Sepharose FF to achieve similar(or even higher) recoveries suggest the excellent chromatographic column performance of the DEAE dextran-FF resins. Finally, both high recovery and purity of BSA and γ-globulin could be easily achieved using the typical DEAE dextran-FF column, FF-D60-DexD160, to separate their binary mixtures,by step gradient elution. The research has provided new insights into the practical application of the series of DEAE-dextran grafted resins in protein chromatography and proved their superiority.展开更多
The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anio...The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.展开更多
In order to explore internal factors for adsorption kinetic effect of miglitol by D001 resin, a batch adsorption operation for miglitol kinetic adsorption at different concentrations, temperatures and vibrating rates ...In order to explore internal factors for adsorption kinetic effect of miglitol by D001 resin, a batch adsorption operation for miglitol kinetic adsorption at different concentrations, temperatures and vibrating rates was investigated in oscillator (SHZ-A), respectively. The different kinetic mathematical model, Webber-Morris kinetic equation, film diffusion coefficient equation and kinetic boundary model were all applied to discuss the adsorption process. The results showed that Type 1 pseudo-second order kinetic equation can be all used to describe miglitol adsorbed by D001 resin at different concentrations, temperatures and vibrating rates. Moreover, the total activation energy (Ea) can be calculated and its value is 9.7 kJ/mol, and then calculated values of the process film diffusion coefficient and pore diffusion coefficient, it may be inferred from these gotten values that the ion exchange process is all mainly controlled by film diffusion. Therefore, the results also suggest that the external adsorption factors such as solute concentration, temperature and vibrating rate for effect of mass transfer diffusion process control of miglitol onto D001 resin are relatively weak.展开更多
The equilibrium adsorption isotherm and kinetic of the sorption process for W and Mo on macro chelating resin D403 were investigated on single Na2 Mo O4 and Na2WO4 solutions.The sorption isotherm results show that the...The equilibrium adsorption isotherm and kinetic of the sorption process for W and Mo on macro chelating resin D403 were investigated on single Na2 Mo O4 and Na2WO4 solutions.The sorption isotherm results show that the adsorption process of W obeys the Freundlich model very well whereas the exchange process with Mo approximately follows the Henry model.The kinetic experiments show that the intraparticle diffusion process was the rate-determining step for W sorption on the resin,and the corresponding activation energy is calculated to be 21.976 k J/mol.展开更多
The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influenc...The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.展开更多
Adsorption of humic, tannic and gallic acids by a macro weakly basic ion-exchange resin JN-01 was studied. The adsorption capacity of this resin for gallic and tannic acids is much higher than that for humic acid, whi...Adsorption of humic, tannic and gallic acids by a macro weakly basic ion-exchange resin JN-01 was studied. The adsorption capacity of this resin for gallic and tannic acids is much higher than that for humic acid, which can be explained on the basis of both their molecular size and ionization degree. Furthermore, humic acid is separated into different components with molecular weight in the range from 2000 Da to 100000 Da by ultra-filter, and their adsorption isotherms on resin JN-01 indicate that humic acid's molecular weight is an important factor which makes significant influence on adsorption. Finally, changes in the amount of Cu^2+ and Pb^2+ adsorbed on resin JN-01 as a function of the concentration of each of these three acids were studied. A large increase in the heavy metal ions uptake is observed in the presence of humic substance, such advantages are due to the interactions between the heavy metal ions and the unbound functional groups of the adsorbed organic acids.展开更多
In light of multiple field experiments in typical tidal areas with active sea-land interaction, corresponding analysis through hydrodynamic simulation and of ion composition evolution all insist on following conclusio...In light of multiple field experiments in typical tidal areas with active sea-land interaction, corresponding analysis through hydrodynamic simulation and of ion composition evolution all insist on following conclusions. Due to the tide, the groundwater level is basically in line with its level but with a slight lag. Moreover, smaller amplitude of such changes were always accompanied by greater distance from shores. In this paper, two salt-freshwater interfaces were identified, namely, a large wedge-shaped interface and an inverted U-shaped one located at K5 (monitoring point). The critical hydraulic gradient of saltwater intrusion was between 0.0345 and 0.0377. Apart from that, mathematical and physical models were adopted to measure the influence of tides, showing a inverse proportion to the hydraulic gradient In addition, characteristics of ionic components can prove that K^+ was adsorbed and Ca^2+ was displaced during saline intrusion, while a reverse process was witnessed during desalting. In summary, cation exchange adsorption plus other complex physical chemical effects would take place during saltwater intrusion.展开更多
The adsorption properties of the four precious metal ions(Ag(Ⅰ),Au(Ⅲ),Pd(Ⅱ)and Pt(Ⅳ))on the commercial Cl--form 717 strongly basic anion-exchange resin were studied in detail.The effects of the contact time,soluti...The adsorption properties of the four precious metal ions(Ag(Ⅰ),Au(Ⅲ),Pd(Ⅱ)and Pt(Ⅳ))on the commercial Cl--form 717 strongly basic anion-exchange resin were studied in detail.The effects of the contact time,solution acidity,and concentrations of Cl - and Pb 2+ ions on the adsorption properties were studied by the batch method.Then,the column method was conducted under the optimized adsorption conditions(pH=3.0).The effects of the sample loading flow rate and the length-to-diameter ratios of the columns were investigated.The precious metal ions adsorbed could not be eluted completely after the saturated adsorption because the precious metal ions were found to be reduced to their metallic states during the adsorption process.So,it is recommended that the commercial Cl--form 717 strongly basic anion-exchange resin should be decomposed directly to recovery the precious metals after the saturated adsorption.展开更多
The adsorption behavior of molybdenum onto D314 was studied with the static adsorption method. The adsorption process was analyzed from thermodynamic and kinetic aspects. The experimental results show that the equilib...The adsorption behavior of molybdenum onto D314 was studied with the static adsorption method. The adsorption process was analyzed from thermodynamic and kinetic aspects. The experimental results show that the equilibrium adsorption data conform satisfactorily to the Langmuir equation. In the adsorption process of D314 for molybdenum, the enthalpy change ΔH is positive when temperature is in the range of 298-338 K, which indicates that the adsorption is an endothermic process, and the elevated temperature benefits to the adsorption. Kinetic analysis shows that the adsorption rate is controlled by intraparticle diffusion and chemical diffusion at the same time. The adsorption mechanism of molybdenum onto D314 was discussed based on IR spectra.展开更多
The study of copper adsorption onto ion exchange resins of anionic type is part of the gold recovery from ammonia-thiosulfate solutions, where copper is the main impurity of the system because it acts as a catalyst of...The study of copper adsorption onto ion exchange resins of anionic type is part of the gold recovery from ammonia-thiosulfate solutions, where copper is the main impurity of the system because it acts as a catalyst of gold dissolution reaction. A study is made of the adsorption and desorption of copper in the form of the complex in an ammonia-thiosulfate media on an ion exchange resin, DOWEX 550A, classified as a strong base, which in its inner structure has a quaternary amine functional group. In the studied pH range copper adsorption increased with increasing pH, while the presence of thiosulfate decreased it, the same as the ammonia content, due to the greater presence of cuprotetramine, . Elution of the copper complexes from the resin was more efficient with sulfite than with perchlorate.展开更多
Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization,...Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.展开更多
To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid so...To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid solutions. Adsorption at different concentrations of nitric acid and thorium, influence of contact time and coexisting metal ions, and effect of NO3– were investigated in detail. It was found that at high HNO3 concentrations,the resins exhibited higher adsorption capacity and better affinity towards thorium. The adsorption kinetics could be described by the pseudo-second order model equation, while the adsorption isotherms were well correlated by the Langmuir model. The maximum capacity towards thorium species on SiPyR-N4 was evaluated at 27–28 mg/g-resin. The thermodynamic parameters indicated the adsorption was an exothermic reaction. The presence of NO3– was found to promote the retention of the thorium species.展开更多
From a number of ion-exchange resins and adsorbents,a macro-pore weak-base type anionion-exchange resin,D354,was selected for the separation of lactic acid.Experimental data showedthat simultaneous ion-exchange and ph...From a number of ion-exchange resins and adsorbents,a macro-pore weak-base type anionion-exchange resin,D354,was selected for the separation of lactic acid.Experimental data showedthat simultaneous ion-exchange and physical adsorption existed in the lactic acid-D354 system.Amathematical model was suggested to simulate the experimental data.Also,the effects of inorganicsalts on the ion-exchange.equilibrium were studied.The difference in ion-exchange equilibrium be-tween DL-and L-lactic acid was observed.展开更多
Experiment was designed under different pH and temperature conditions to analysis the NH4+ exchange capacity of Na+-vermiculite,Ca2+-vermiculite and Mg2+-vermiculite clay minerals pre-treated using NaCl,CaCl2 and MgCl...Experiment was designed under different pH and temperature conditions to analysis the NH4+ exchange capacity of Na+-vermiculite,Ca2+-vermiculite and Mg2+-vermiculite clay minerals pre-treated using NaCl,CaCl2 and MgCl2 solutions respectively.The results indicated that the exchange reactions occurred most rapidly at the proceeding 80 minutes and approached to equilibrium by about 120 minutes.The exchange quantity of ammonium on the vermiculite(at initial ammonium concentration of 673mg/L)varied with pH with a peak value of 28.36mg/g on Na+-vermiculite,23.01mg/g on Ca2+-vermiculite,20.14mg/g on Mg2+-vermiculite,18.04mg/g on natural vermiculite at pH 7.The exchange and adsorption isotherm of NH4+ on cation-vermiculite can be described by Langmuir equation.展开更多
基金Funded by National Natural Science Foundation of China(Nos.52172019 and 52072148)Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022K1100)。
文摘In this work,the structure,viscosity and ion-exchange process of Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) glasses with different Al_(2)O_(3)/SiO_(2) molar ratios were investigated.The results showed that,with increasing Al_(2)O_(3)/SiO_(2) ratio,the simple structural units Q_(1) and Q_(2) transformed into highly aggregated structural units Q_(3) and Q_(4),indicating the increase of polymerization degree of glass network.Meanwhile,the coefficient of thermal expansion decreased from 9.23×10^(-6)℃^(-1) to 8.88×10^(-6)℃^(-1).The characteristic temperatures such as melting,forming,softening and glass transition temperatures increased with the increase of Al_(2)O_(3)/SiO_(2) ratio,while the glasses working temperature range became narrow.The increasing Al_(2)O_(3)/SiO_(2) ratio and prolonging ion-exchange time enhanced the surface compressive stress(CS)and depth of stress layer(DOL).However,the increase of ion exchange temperature increased the DOL and decreased the CS affected by stress relaxation.There was a good linear relationship between stress relaxation and surface compressive stress.Chemical strengthening significantly improved the hardness of glasses,which reached the maximum value of(622.1±10)MPa for sample with Al_(2)O_(3)/SiO_(2) ratio of 0.27 after heat treated at 410℃for 2 h.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0402400)the National Natural Science Foundation of China(Grant Nos.11974358 and 11934004)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB34020000)the Heavy Ion Research Facility in Lanzhou(HIRFL).
文摘The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first time we investigated the state-selective single electron capture processes for S^(q+)–He and H_(2)(q=11–15)collision systems at an impact energy of q×20 keV and obtained the relative state-selective cross sections.The results indicate that only a few principal quantum states of the projectile energy level are populated in a single electron capture process.In particular,the increase of the projectile charge state leads to the population of the states with higher principal quantum numbers.It is also shown that the experimental averaged n-shell populations are reproduced well by the over-barrier model.The database is openly available in Science Data Bank at 10.57760/sciencedb.j00113.00091.
基金Project supported bythe Japan Societyfor the Promotion of Science (JSPS)
文摘Ce (Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol·L^-1) and temperature (278 ~318 K) on Ce( Ⅳ ) sorption efficiency was investigated. Sorption increased with increasing nitric acid concentration, indicating that [Ce(NO3)6]^2- complex is the main adsorbed Ce(Ⅳ) species. Oxidation of sorbents by adsorbed Ce ( Ⅳ ) species resulting in Ce ( Ⅲ ) release to the solution was observed. Pyridine based anion exchangers exhibited higher oxidation stability compared to the commercial strong base anion exchanger. Ce( Ⅳ ) reduction was temperature dependent and obeyed pseudo-first-order reaction kinetics. Column separation of Ce ( Ⅳ ) from La ( Ⅲ ) and Y ( Ⅲ ) was carried out from 6 mol·L^-1 nitric acid with PVP based anion exchanger. Reasonable Ce (Ⅳ) breakthrough capacity (0.7 mol·kg^-1 PVP) was achieved. No remarkable decrease of capacity was observed within 3 consequent runs. In contrast, Ce (Ⅲ) leakage due to reduction decreased and breakthrough capacity slightly increased. This effect was more pronounced with increasing temperature. Regeneration with 0.1 mol·L^- 1 nitric acid was successful (recovery 100% ± 4% ) and Ce solution of high purity ( 〉 99.97% ) with respect to La and Y content was gained.
基金support provided by the National Nature Science Fund(No.50778088)China National Funds for Distinguished Young Scientists(No.50825802)Resources Special Subject of National High Technology Research & Development Project(863 project,No.2006AA06Z383),China.
文摘There are numerous impurities in wet-process phosphoric acid,among which manganese is one of detrimental metallic impurities,and it causes striking negative effects on the industrial phosphoric acid production and downstream commodity.This article investigated the adsorption behavior of manganese from phosphoric acid employing Sinco-430 cationic ion-exchange resin.Resorting FT-IR and XPS characterizations,the adsorption mechanism was proved to be that manganese was combined with sulfonic acid group.Several crucial parameters such as temperature,phosphoric acid content and resin dose were studied to optimize adsorption efficiency.Through optimization,removal percentage and sorption capacity of manganese reached 53.12 wt%,28.34 mg·g^-1,respectively.Pseudo-2nd-order kinetic model simulated kinetics data best and the activation energy was evaluated as 6.34 kJ·mol^-1 for the sorption reaction of manganese.In addition,the global adsorption rate was first controlled by film diffusion process and second determined by pore diffusion process.It was found that the resin could adsorb up to 50.24 mg·g^-1 for manganese.Equilibrium studies showed that Toth adsorption isotherm model fitted best,followed by Temkin and Langmuir adsorption isotherm models.Thermodynamic analysis showed that manganese adsorption was an endothermic process with enhanced randomness and spontaneity.
基金supported by the National Natural Science Foundation of China (Nos. 21878222 and 21621004).
文摘In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption and chromatographic behavior. It was found that the resin with an ionic capacity of 630 mmol·L^-1(FF-PEI-CR630)possessed high adsorption performance towards lysozyme at 0–100 mmol·L^-1 Na Cl. Therefore, in this work,FF-PEI-CR630 was selected to study the influences of pH and ionic strength(IS) on protein adsorption and chromatographic behavior towards lysozyme. The increase of lysozyme adsorption capacity in the pH range of 6 to 10 was observed. However, the uptake rate decreased in the pH range of 6 to 8 and then remained essentially unchanged from pH 8 to pH 10. Increasing IS led to decreased protein adsorption capacity and increased uptake rate in different pH ranges. Besides, FF-PEI-CR630 maintained dynamic binding capacity as high as over150 mg·ml^-1 at pH 8–10 without NaCl. The research has thus provided insight into the selection of proper pH and IS conditions for protein purification by using FF-PEI-CR630.
基金Supported by the National Natural Science Foundation of China(21406160,21621004)
文摘Our previous studies on bovine serum albumin(BSA) adsorption to diethylaminoethyl dextran(DEAE dextran,DexD, grafting-ligand) and DEAE(D, surface-ligand) modified Sepharose FF resins found that all the grafted resins(FF-DexD and FF-D-DexD) exhibited extremely fast uptake rate(effective diffusivity, D_e, D_e/D_O> 1.4),which was six times greater than the ungrafted resins(D_e/D_O < 0.3). In this work, the influence of ionic strength(IS) on 6 typical DEAE dextran-grafted resins was investigated. Bath adsorption equilibria and kinetics, breakthrough, and linear gradient elution experiments were conducted. Commercial DEAE Sepharose FF was used for comparison. It is found that protein adsorption capacities on DEAE dextran-FF resins and the commercial resin decreased with increasing IS, but DEAE dextran-FF resins exhibited much higher capacity sensitivity to salt concentration. Besides, steeper decrease of adsorption capacities could be obtained at higher graftingligand or surface-ligand density. It is worth noting that the facilitating role of surface-ligand to the "chain delivery" effect was weakened after adding salt, leading to the less improvement in uptake rate by increasing surface-ligand density at higher IS. Although the uptake rates of the DEAE dextran-FF resins increased first and then decreased with increasing IS, they kept the extremely high level of De values(D_e/D_O > 1.1) at the their working/binding IS range. Moreover, the DEAE dextran-FF resin displayed much higher adsorption capacities and De values than commercial ungrafted resin in their working condition. Furthermore, the column results of DEAE dextran-FF resins presented higher dynamic binding capacities than and similar elution ISs with DEAE Sepharose FF to achieve similar(or even higher) recoveries suggest the excellent chromatographic column performance of the DEAE dextran-FF resins. Finally, both high recovery and purity of BSA and γ-globulin could be easily achieved using the typical DEAE dextran-FF column, FF-D60-DexD160, to separate their binary mixtures,by step gradient elution. The research has provided new insights into the practical application of the series of DEAE-dextran grafted resins in protein chromatography and proved their superiority.
文摘The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy, and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.
文摘In order to explore internal factors for adsorption kinetic effect of miglitol by D001 resin, a batch adsorption operation for miglitol kinetic adsorption at different concentrations, temperatures and vibrating rates was investigated in oscillator (SHZ-A), respectively. The different kinetic mathematical model, Webber-Morris kinetic equation, film diffusion coefficient equation and kinetic boundary model were all applied to discuss the adsorption process. The results showed that Type 1 pseudo-second order kinetic equation can be all used to describe miglitol adsorbed by D001 resin at different concentrations, temperatures and vibrating rates. Moreover, the total activation energy (Ea) can be calculated and its value is 9.7 kJ/mol, and then calculated values of the process film diffusion coefficient and pore diffusion coefficient, it may be inferred from these gotten values that the ion exchange process is all mainly controlled by film diffusion. Therefore, the results also suggest that the external adsorption factors such as solute concentration, temperature and vibrating rate for effect of mass transfer diffusion process control of miglitol onto D001 resin are relatively weak.
基金Project (2014CB643405) supported by National Research Development Program of China
文摘The equilibrium adsorption isotherm and kinetic of the sorption process for W and Mo on macro chelating resin D403 were investigated on single Na2 Mo O4 and Na2WO4 solutions.The sorption isotherm results show that the adsorption process of W obeys the Freundlich model very well whereas the exchange process with Mo approximately follows the Henry model.The kinetic experiments show that the intraparticle diffusion process was the rate-determining step for W sorption on the resin,and the corresponding activation energy is calculated to be 21.976 k J/mol.
基金Project(2005) supported by the Basic Technology Research Item of Explosive Industry, China
文摘The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.
基金supported by the State Key Program of National Natural Science(No.50938004)the National Nature Science Fund(No.50778088)China National Funds for Distinguished Young Scientists (No.50825802)
文摘Adsorption of humic, tannic and gallic acids by a macro weakly basic ion-exchange resin JN-01 was studied. The adsorption capacity of this resin for gallic and tannic acids is much higher than that for humic acid, which can be explained on the basis of both their molecular size and ionization degree. Furthermore, humic acid is separated into different components with molecular weight in the range from 2000 Da to 100000 Da by ultra-filter, and their adsorption isotherms on resin JN-01 indicate that humic acid's molecular weight is an important factor which makes significant influence on adsorption. Finally, changes in the amount of Cu^2+ and Pb^2+ adsorbed on resin JN-01 as a function of the concentration of each of these three acids were studied. A large increase in the heavy metal ions uptake is observed in the presence of humic substance, such advantages are due to the interactions between the heavy metal ions and the unbound functional groups of the adsorbed organic acids.
基金financial support should be credited to the National Natural Science Foundation of China (NSFC grant No. 4152249)Basic Research Project of Chinese Academy of Geological Sciences, China Geological Survey (JYWF 20181101)China Geological Survey Project (DD20160910)
文摘In light of multiple field experiments in typical tidal areas with active sea-land interaction, corresponding analysis through hydrodynamic simulation and of ion composition evolution all insist on following conclusions. Due to the tide, the groundwater level is basically in line with its level but with a slight lag. Moreover, smaller amplitude of such changes were always accompanied by greater distance from shores. In this paper, two salt-freshwater interfaces were identified, namely, a large wedge-shaped interface and an inverted U-shaped one located at K5 (monitoring point). The critical hydraulic gradient of saltwater intrusion was between 0.0345 and 0.0377. Apart from that, mathematical and physical models were adopted to measure the influence of tides, showing a inverse proportion to the hydraulic gradient In addition, characteristics of ionic components can prove that K^+ was adsorbed and Ca^2+ was displaced during saline intrusion, while a reverse process was witnessed during desalting. In summary, cation exchange adsorption plus other complex physical chemical effects would take place during saltwater intrusion.
文摘The adsorption properties of the four precious metal ions(Ag(Ⅰ),Au(Ⅲ),Pd(Ⅱ)and Pt(Ⅳ))on the commercial Cl--form 717 strongly basic anion-exchange resin were studied in detail.The effects of the contact time,solution acidity,and concentrations of Cl - and Pb 2+ ions on the adsorption properties were studied by the batch method.Then,the column method was conducted under the optimized adsorption conditions(pH=3.0).The effects of the sample loading flow rate and the length-to-diameter ratios of the columns were investigated.The precious metal ions adsorbed could not be eluted completely after the saturated adsorption because the precious metal ions were found to be reduced to their metallic states during the adsorption process.So,it is recommended that the commercial Cl--form 717 strongly basic anion-exchange resin should be decomposed directly to recovery the precious metals after the saturated adsorption.
基金Project(51104186)supported by the National Natural Science Foundation of China
文摘The adsorption behavior of molybdenum onto D314 was studied with the static adsorption method. The adsorption process was analyzed from thermodynamic and kinetic aspects. The experimental results show that the equilibrium adsorption data conform satisfactorily to the Langmuir equation. In the adsorption process of D314 for molybdenum, the enthalpy change ΔH is positive when temperature is in the range of 298-338 K, which indicates that the adsorption is an endothermic process, and the elevated temperature benefits to the adsorption. Kinetic analysis shows that the adsorption rate is controlled by intraparticle diffusion and chemical diffusion at the same time. The adsorption mechanism of molybdenum onto D314 was discussed based on IR spectra.
文摘The study of copper adsorption onto ion exchange resins of anionic type is part of the gold recovery from ammonia-thiosulfate solutions, where copper is the main impurity of the system because it acts as a catalyst of gold dissolution reaction. A study is made of the adsorption and desorption of copper in the form of the complex in an ammonia-thiosulfate media on an ion exchange resin, DOWEX 550A, classified as a strong base, which in its inner structure has a quaternary amine functional group. In the studied pH range copper adsorption increased with increasing pH, while the presence of thiosulfate decreased it, the same as the ammonia content, due to the greater presence of cuprotetramine, . Elution of the copper complexes from the resin was more efficient with sulfite than with perchlorate.
文摘Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.
基金Supported by the National Natural Science Foundation of China(No.91026019)
文摘To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid solutions. Adsorption at different concentrations of nitric acid and thorium, influence of contact time and coexisting metal ions, and effect of NO3– were investigated in detail. It was found that at high HNO3 concentrations,the resins exhibited higher adsorption capacity and better affinity towards thorium. The adsorption kinetics could be described by the pseudo-second order model equation, while the adsorption isotherms were well correlated by the Langmuir model. The maximum capacity towards thorium species on SiPyR-N4 was evaluated at 27–28 mg/g-resin. The thermodynamic parameters indicated the adsorption was an exothermic reaction. The presence of NO3– was found to promote the retention of the thorium species.
基金Supported by the National Natural Science Foundation of China
文摘From a number of ion-exchange resins and adsorbents,a macro-pore weak-base type anionion-exchange resin,D354,was selected for the separation of lactic acid.Experimental data showedthat simultaneous ion-exchange and physical adsorption existed in the lactic acid-D354 system.Amathematical model was suggested to simulate the experimental data.Also,the effects of inorganicsalts on the ion-exchange.equilibrium were studied.The difference in ion-exchange equilibrium be-tween DL-and L-lactic acid was observed.
文摘Experiment was designed under different pH and temperature conditions to analysis the NH4+ exchange capacity of Na+-vermiculite,Ca2+-vermiculite and Mg2+-vermiculite clay minerals pre-treated using NaCl,CaCl2 and MgCl2 solutions respectively.The results indicated that the exchange reactions occurred most rapidly at the proceeding 80 minutes and approached to equilibrium by about 120 minutes.The exchange quantity of ammonium on the vermiculite(at initial ammonium concentration of 673mg/L)varied with pH with a peak value of 28.36mg/g on Na+-vermiculite,23.01mg/g on Ca2+-vermiculite,20.14mg/g on Mg2+-vermiculite,18.04mg/g on natural vermiculite at pH 7.The exchange and adsorption isotherm of NH4+ on cation-vermiculite can be described by Langmuir equation.