Influence of Al_(2)O_(3)/SiO_(2) Ratio on the Structure and Properties of Na^(+)/K^(+)Ion Exchange Na_(2)O-MgO-Al_(2)O_(3)-SiO_(2) Glasses

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.

Simulation of charge-exchange induced NBI losses on EAST

The neutral beam injection is widely adopted in tokamaks as a key heating tool,playing a crucial role in generating burning plasmas.However,the loss of beam ions can damage the first wall and reduce the heating efficiency,resulting in failure to maintain steady-state conditions.In this work,the effect of neutral particles in the edge on fast ions generated by NBI in the Experimental Advanced Superconducting Tokamak(EAST)device is studied using the particle tracer code(PTC).The poloidal distribution of neutral particles is calculated by edge plasma simulation code SOLPS-ITER.In this simulation,four beam lines in EAST are considered:co-current tangential(co-tang),co-current perpendicular(co-perp),counter-current tangential(ctr-tang)and counter-current perpendicular(ctr-perp).It is shown that,in the absence of neutral particles,the loss fraction of ctr-injection is considerably higher than that of the co-injection.When considering the neutral particles,it is found that the ctr-perp injection demonstrates a significant variation in particles loss fraction(ranging from 18.56%to 25.42%)compared to the other three injection configurations.In terms of the loss fraction induced by neutral particles,ctr-injection exceeds co-injection,and perpendicular configuration exceeds tangential configuration.Furthermore,the difference of charge exchange ratios of three different energy(full energy,half energy,one third energy)of the four injections can be attributed to variations in the poloidal trajectories associated with each of these injections.Moreover,approximately half of fast ions which undergo neutralization directly lose to the first wall while the rest re-enter the bulk plasma and re-ionize.Except for the ctr-tang injection,the reionization ions from the other three injections exhibit effective confinement.

State-selective charge exchange cross sections in collisions of highly-charged sulfur ions with helium and molecular hydrogen

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.

STUDY ON THE SEPARATION OF GLUTAMIC ACID BY ION-EXCHANGE

The feasibility of recavering glutamic acid by ion exchange method with macroporous resins was investigated. Their adsorption properties in static state and the effective factors,such as pH, concentration of feed and the ratio of ammonium ion toglutamic acid,were systematically explored. The best conditions of separating glutamic acid from mother liquid were obtained.

Synthesis, structure characterization, and ion exchange properties of a novel open-framework ecomaterial silicotitanate

A novel open-framework ecomaterial silicotitanate (Na_4Ti_4Si_3O_(10)) wassynthesized by a combination of solgel and hydrothermal methods. The investigation on ion exchangeproperties shows that Na_4Ti_4Si_3O_(10) exhibits high ad-sorption for cesium, i.e., K_d is as highas 60 000 mL/g in neutral solution. The crystal structure of Na_4Ti_4Si_3O_(10) was characterized byX-ray difiraction (XRD), scanning electronic microscope (SEM), transmission electron microscope(TEM), Raman spectrum, differential thermal and thermogravimetric analysis (DTA/TGA), inductivelycoupled plasma (ICP), and X fluorescence analysis. The compound is tetragonal, P4_2, a=b = 0.781 10nm, c = 1.196 45 nm, alpha =beta = gamma = 90 deg, Z = 4, and R^a = 0.041; Na_4Ti_4Si_3O_(10) has athree dimensional framework consisting of Ti-O octahedral clusters and Si-O tetrahedra. The resultsshow that Na_4Ti_4Si_3O_(10) has good chemical stability, thermal stability, and high cesium ionexchange capacity in the whole pH range.

Implications from protein uptake kinetics onto dextran-grafted Sepharose FF coupled with ion exchange and affinity ligands

Our previous studies have reported the presence of "chain delivery" effects of protein adsorption onto ion exchangers with polymer-grafted ion-exchange groups, such as dextran-grafted and poly(ethylenimine)-modified Sepharose gels. However, it is unclear if the "chain delivery" occurs on affinity adsorption with specific interactions. This work is designed to address this issue. A dextran-grafted Sepharose gel was prepared, and then the matrix was modified using diethylaminoethyl, a typical ion-exchange group, or octapeptide(FYCHWQDE), an affinity ligand for human immunoglobulin G(h Ig G) to prepare ion-exchange or affinity adsorbents, respectively.Results of h Ig G adsorption showed that the uptake rate represented by the effective diffusivity of h Ig G onto the dextran-grafted ion exchangers was obviously enhanced by the dextran grafting, indicating the presence of"chain delivery" of the bound proteins on the charged groups on the dextran chains. By contrast, the effective diffusivity of h Ig G changed little as ligand density increased on the dextran-grafted FYCHWQDE adsorbents.Their adsorption capacities decreased and effective diffusivities were not accelerated by the dextran grafting.Thus, this work clarified that grafted dextran could not accelerate h Ig G uptake rate on the affinity resins, or in other words, chain delivery did not occur on the specific interaction-based affinity adsorption.

Adsorption behavior of Sb(Ⅲ) in single and binary Sb(Ⅲ)-Fe(Ⅱ) systems on cationic ion exchange resin: Adsorption equilibrium, kinetic and thermodynamic aspects

The present study dealt with the mechanism of competitive adsorption of Sb(Ⅲ)and Fe(Ⅱ)ions from a copper-containing aqueous solution on Purolite S957,a commercially available cationic ion-exchange adsorbent.Experiments were conducted using aqueous copper sulfate solutions containing either single or conjoint ions,using both sedentary and batch adsorption techniques to ascertain the sensitivity of the adsorption process to variation in p H,mass of resin,contact time,and temperature as well as establishing the optimal range of variables for maximum ion removal.The data from single ion adsorption tests were fitted by non-linear regression techniques to Henry,Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.Freundlich isotherm for Sb(Ⅲ)and Freundlich and Henry models for Fe(Ⅱ)solutions best express the adsorption equilibrium data;while for binary ion electrolytes,the extended Freundlich model fitted the data satisfactorily.The kinetic model adequately describing adsorption was shown to be the pseudo-first-order,underscoring the dominant role of physical adsorption playing in the process.Thermodynamic parameters for the adsorption process reveal differences in the Sb(Ⅲ)adsorption mechanism from single ion and Sb(Ⅲ)-Fe(Ⅱ)containing electrolytes.The adsorption of Sb(Ⅲ)alone is endothermic,whereas the process becomes exothermic in the Sb(Ⅲ)-Fe(Ⅱ)system.

Preparation and characterization of Ag^+ ion-exchanged zeolite-Matrimid~5218 mixed matrix membrane for CO_2/CH_4 separation

In this work, the zeolite-Y was ion-exchanged by introducing silver cations into the framework of microsized nano-porous sodium zeolite-Y using a liquid-phase ion exchanged method. The Ag+ion-exchanged zeolite, was then embedded into the Matrimid5218 matrix to form novel mixed matrix membranes(MMMs). The particles and MMMs were characterized by ultraviolet-visible diffuse reflectance spectroscopy(UV–vis DRS), N2adsorption–desorption isotherm, X-ray diffraction(XRD), Fourier transform infrared(FTIR) and scanning electron microscopy(SEM). Furthermore, the effects of filler content(0–20wt%) on pure and mixed gas experiments, feed pressure(2–20 bar) and operating temperature(35–75 oC)on CO2/CH4transport properties of Matrimid/Ag Y MMMs were considered. Characterization results confirmed an appropriate ion-exchange treatment of the zeolites. The SEM results confirmed the superior interfacial adhesion between polymer and zeolites, particularly in the case of Matrimid/Ag Y membranes.This is due to the proper silverous zeolite/Matrimid functional groups’ interactions. The gas permeation results showed that the CO2permeability increased about 123%, from 8.34 Barrer for pure Matrimid to18.62 Barrer for Matrimid/Ag Y(15 wt%). The CO2/CH4selectivity was improved about 66%, from 36.3 for Matrimid to 60.1 for Matrimid/Ag Y(15 wt%). The privileged gas separation performance of Matrimid/Ag Y(15 wt%) was the result of a combined effect of facilitated transport mechanism of Ag+ions as well as the intrinsic surface diffusion mechanism of Y-type zeolite. In order to survey the possibility of using the developed MMMs in industry, the CO2-induced plasticization effect and mixed gas experiment were accomplished. It was deduced that the fabricated MMMs could maintain the superior performance in actual operating conditions.

Kinetic Study of Esterification of Lactic Acid with Isobutanol and n-Butanol Catalyzed by Ion-exchange Resins

The esterification reactions of lactic acid with isobutanol and n-butanol have been studied in the presence of acid ion-exchange resin Weblyst D009. The influences of catalyst loading, stirrer speed, catalyst particle size, initial reactant molar ratio and temperature on the reaction rate have been examined. Experimental kinetic data were correlated by using the pseudo-homogeneous, Langnluir-Hinshelwood and Eley-Rideal models. Nonideality of the liquid phase was taken into account by using activities instead of molar fractions. The activity coefficients were calculated according to the group contribution method UNIFAC. Provided that the nonideality of the liquid is taken into account, the esterification kinetics of lactic acid with isobutanol and n-butanol catalyzed by the acid ion-exchange resin can be described using all threemodels with reasonable errors.

In-situ transformation of Bi_2WO_6 to highly photoreactive Bi_2WO_6@Bi_2S_3 nanoplate via ion exchange

As a two dimensional(2D)visible‐light‐responsive semiconductor photocatalyst,the photoreactivity of Bi2WO6 is not high enough for practical application owing to its limited response to visible light and rapid recombination of photogenerated electron‐hole pairs.In this paper,2D core‐shell structured Bi2WO6@Bi2S3 nanoplates were prepared by calcination of a mixture of Bi2WO6(1.3 g)and a certain amount of Na2S·9H2O(0–3.0 g)at 350°C for 2 h.The reactivity of the resulting photocatalyst materials was evaluated by photocatalytic degradation of Brilliant Red X‐3B(X3B),an anionic dye,under visible light irradiation(?>420 nm).As the amount of Na2S·9H2O was increased from 0 to 1.5 g,the degradation rate constant of X3B sharply increased from 0.40×10?3 to 6.6×10?3 min?1.The enhanced photocatalytic activity of Bi2WO6@Bi2S3 was attributed to the photosensitization of Bi2S3,which greatly extended the light‐responsive range from the visible to the NIR,and the formation of a heterojunction,which retarded the recombination rate of photogenerated electron‐hole pairs.However,further increases in the amount of Na2S·9H2O(from 1.5 to 3.0 g)resulted in a decrease of the photocatalytic activity of the Bi2WO6@Bi2S3 nanoplates owing to the formation of a photo‐inactive NaBiS2 layer covering the Bi2WO6 surface.

Concentration and separation of vanadium from alkaline media by strong alkaline anion-exchange resin 717

With strong alkaline anion-exchange resin 717 as the sorbent and NaOH solution as the eluent, a study on the sorption from alkaline solution and elution of vanadium（V）, silicon（iv）, and aluminium（III） was carried out. Different parameters affecting the sorption and elution process, including temperature, pH values as well as the ratio of resin to solution, were investigated. The results show that sorption degree of vanadium（V） increases with a decrease ofpH values, and V（V） ions are easier sorbed than Si（IV） and AI（III） ions under the same conditions. The sorption degree ofV（V）, Si（IV）, and AI（III） at pH 9.14 for 15 man are 90.6%, 33.5%, and 21.6%, respectively. Si（IV）, AI（III）, and V（V） ions sorbed on 717 resin were eluted by use of 2 mol·L^-1 NaOH solution; the desorption degree ofV（V）, Si（IV）, and AI（III） for 5 min are 81.7 %, 99.1%, and 99.3%, respectively.

Synthesis of Pb-Feldspar by Ion Exchange Reaction and Its Implications

Feldspar and Pb（NO3）2 were mixed and reacted at T=380℃ to synthesize Pb-feldspar. In the XRD （X-ray diffraction） pattern of the product, the d values （crystal lattice spacing） of the five peaks are 0.654, 0.342, 0.332, 0.327 and 0.257 nm. The XPS analysis results show that the binding energy of Pb 4f（7/2） in the feldspar was between 137.81-138.03 eV. Pb^2＋ can replace alkali and alkali earth cations in the feldspar structure through ion exchange reaction to form Pb-feldspar.

Lysozyme adsorption to cation exchanger derivatized by sequential modification of poly(ethylenimine)-Sepharose with succinic anhydride and ethanolamine: Effect of p H and ionic strength

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.

Structure and resistance of concentration polar layer on cation exchange membrane-solution interface

Membrane/solution interface consists of a neutral concentration polai layer(CPL) and a charge layer(CL) under external electrical field, and the neutral CPL can be neglected under high frequency AC electrical field. The relationship of CL thickness e with electrolyte concentration C and fixed ion exchange sites density σ in membrane surface layer can be expressed as e

Profile Measurement of Ion Temperature and Toroidal Rotation Velocity with Charge Exchange Recombination Spectroscopy Diagnostics in the HL-2A Tokamak

This paper deals with the profile measurement of impurity ion temperature and toroidal rotation velocity that can be achieved by using the charge exchange recombination spectrum （CXRS） diagnostics tool built on the HL-2A toknmak. By using CXRS, an accurate impurity ion temperature and toroidal plasma rotation velocity profile can be achieved under the condition of neutrM beam injection （NBI） heating. Considering the edge effect of the line of CVI 529.06 nm （n= 8-7）, which contains three lines （active exciting spectral line （ACX）, passivity exciting spectral line （PCX） and electron exciting spectral line （ICE））, and using three Gaussian fitted curves, we obtain the following experimental results： the core ion temperature of HL-2A device is nearly thousands of eV, and the plasma rotation velocity reaches about 104 m· s^-1. At the end of paper, some explanations are presented for the relationship between the curves and the inner physical mechanism.

Taste masking of ciprofloxacin by ion-exchange resin and sustain release at gastric-intestinal through interpenetrating polymer network

The aim of the study was to taste mask ciprofloxacin(CP)by using ion-exchange resins(IERs)followed by sustain release of CP by forming interpenetrating polymer network(IPN).IERs based on the copolymerization of acrylic acid with different cross linking agents were synthesised.Drug-resin complexes(DRCs)with three different ratios of drug to IERs(1:1,1:2,1:4)were prepared&evaluated for taste masking by following in vivo and in vitro methods.Human volunteers graded ADC 1:4,acrylic acid-divinyl benzene(ADC-3)resin as tasteless.Characterization studies such as FTIR,SEM,DSC,P-XRD differentiated ADC 1:4,from physical mixture(PM 1:4)and confirmed the formation of complex.In vitro drug release of ADC 1:4 showed complete release of CP within 60 min at simulated gastric fluid(SGF)i.e.pH 1.2.IPN beads were prepared with ADC 1:4 by using sodium alginate(AL)and sodium alginate-chitosan(AL-CS)for sustain release of CP at SGF pH and followed by simulated intestinal fluid(SIF i.e.pH 7.4).FTIR spectra confirmed the formation of IPN beads.The release of CP was sustain at SGF pH(<20%)whereas in SIF media it was more(>75%).The kinetic model of IPN beads showed the release of CP was non-Fickian diffusion type.

Low-cost and efficient visible-light-driven CaMg(CO_3)_2@Ag_2CO_3 microspheres fabricated via an ion exchange route

CaMg(CO3)2microspheres were prepared and used as hard templates to fabricate a series of CaMg(CO3)2@Ag2CO3composite microspheres via a fast and low‐cost ion exchange process.The effects of ion exchange time and temperature on the physicochemical properties and photocatalytic activities of the composite microspheres were studied through photocatalytic degradation of Acid Orange II under xenon lamp irradiation.The obtained samples were analyzed by X‐ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,UV‐vis diffuse reflectance spectroscopy,N2physical adsorption,and photocurrent tests.The CaMg(CO3)2@Ag2CO3sample with the highest activity was obtained with an ion exchange time of4h and temperature of40°C.The degradation rate of Acid Orange II by this sample reached83.3%after15min of light irradiation,and the sample also performed well in phenol degradation.The CaMg(CO3)2@Ag2CO3produced under these ion exchange conditions showed a well‐ordered hierarchical morphology with small particle sizes,which was beneficial to light absorption and the transfer of photoelectrons(e-)and holes(h+)to the catalyst surface.Moreover,the separation of photogenerated carriers over the composites was greatly improved relative to bare CaMg(CO3)2.Despite the very low content of Ag2CO3(2.56%),excellent photocatalytic performance was obtained over the CaMg(CO3)2@Ag2CO3microspheres.

Behaviour of radioactive iodide and bromide ions from aqueous solution on ion exchange resins Amberlite IRA-400

The ion exchange resin Amberlite IRA-400 in iodide and bromide form where equilibrated separately with the respective labeled iodide and bromide ion solution of different concen-trations varying from 0.005M to 0.100M in the temperature range of 32.0 oC to 48.0 oC. The dis-tribution coefficient Kd values calculated for iodide and bromide ion exchange increases with rise in ionic concentration of the external solution, however with rise in temperature the Kd values calculated where found to decrease. Also the Kd values calculated where higher for iodide exchange than bromide exchange. Among the different alternative techniques available for obtaining the Kd values, the radio-active tracer technique used in the present ex-perimental work offers high detection sensitivity. It is expected that the distribution coefficient data obtained from such experimental work will significant in environmental impact assessment on the disposal of radioactive waste.

Deep removal of copper from cobalt sulfate electrolyte by ion-exchange

SP-C was applied for the removal of Cu^2＋ from simulated cobalt sulfate electrolyte containing Co2＋ 50 g/L and Cu2＋ 0.5-2.0 g/L. Experimental conditions included pH of 2-4, temperature of 20-60℃ and contact time of 10-40 min. The investigation demonstrated that SP-C had recommendable efficiency in adsorbing Cu2＋ from the electrolyte with 25- to 100-fold of Co2＋ The optimal adsorption conditions of SP-C were pH of 4, contact time of 30 min and ambient temperature. The study also showed that the loaded resin could be effectively eluted with 2.0 mol/L H2SO4 solution at a contact time of 40 min; the peak concentration of Cu2＋ in the eluate was about 35 g/L. The sorption characteristics of Cu2＋ by SP-C could be described by Langrnuir isotherm and the pseudo second-order kinetic equation. Infrared spectra showed that nitrogen atoms in the functional group coordinated with Cu2＋ to form coordination bands.

Synthesis, characterization and antimicrobial activity of alkaline ion-exchanged ZnO/bentonite nanocomposites

Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by placing bentonite in a melting bath of ZnSO4 for 10, 20, 40, 60 and 90 rain. The complexes were characterized by XRD, SEM and DRS. XRD analyses and SEM observations confirmed the diffusion of zinc to the clay surfaces. Antibacterial activity tests against Escherichia coli showed that bentonite did not present any antibacterial properties, but after alkaline ion exchange treatment, inhibition was noted. The highest antibacterial activity was observed with ZnO/bentonite composite alkaline ion exchange for 60 and 90 rain. Interestingly, the leaching test indicated that ZnO/bentonite did not present any risk for drinking water treatment.