Effects of ion-exchange on the pervaporation performance and microstructure of NaY zeolite membrane

Pervaporation performance of NaY zeolite membranes is improved by ion-exchange with di-valent nitrate salt.Different nitrate salts,including Co(NO_(3))_(2),Mg(NO_(3))_(2),Zn(NO_(3))_(2),Ca(NO_(3))_(2),Cu(NO_(3))_(2),KNO_(3),and AgNO_(3),have great effects on the channel structure and water affinity of the NaY zeolite membrane.When the concentration of nitrate salt,ion-exchange temperature and time are 0.1 mol·L^(-1),50℃and 2 h,the ion-exchange degree order of NaY zeolites is Ag^(+)>K^(+)>Ca^(2+)>Zn^(2+)>>Co^(2+)>Mg^(2+).Especially,Ag^(+)and K^(+)cation exchange degree of NaY zeolites are achieved to 96.54% and 82.77% in this work.BET surface,total pore capacity,pore size distribution and water contact angle of the ion-exchanged NaY zeolites are all disordered by mono-and di-valent cations.Di-valent nitrate salt is favor for increasing the dehydration performance of NaY zeolite membranes by ion-exchange.When the ion-exchange solution is Zn(NO_(3))_(2),the total flux variation and separation factor variation of the NaY membrane(M-5)are -45% and 230% for separation of 10%(mass)H_(2)O/EtOH mixture by pervaporation,and the ion-exchanged membranes showed good reproducibility.

Tribological Properties of Magnesium Ion-exchanged α-Zirconium Phosphate as a Solid Lubricant Additive in Lithium Grease

Magnesium ion-exchanged a-zirconium phosphates(Mg-α-ZrP) with particle sizes of 600 and 80 nm were prepared through the sealed ion-exchange and one-step hydrothermal synthesis methods, respectively. It was found that larger particles of Mg-α-ZrP had a higher load-carrying capacity than that of smaller particles, whereas smaller Mg-α-ZrP particles had better anti-wear properties than that of larger Mg-α-ZrP particles under mild loads. The correlation between the particle size of the sample and the surface roughness of the friction pair thus seems to be a key factor influencing the performance.

Preparation of Highly Dispersed Antimony-doped Tin Oxide Nano-powder via Ion-exchange Hydrolysis of SnCl_4 and SbCl_3 and Azeotropic Drying

Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using： （1） an ion-exchange hydrolysis to remove chlorine ions, and （2） isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.

Effective adsorptive denitrogenation from model fuels over yttrium ion-exchanged Y zeolite

The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y(YY)using batch adsorption experiments was studied at 25℃and 0.1 MPa.YY was prepared by treating NaY with Y(NO3)3 solution twice via liquid ion-exchange method.NaY and YY were both characterized by XRD,SEM,N2 adsorption,XRF,NH3-TPD,and pyridine-FTIR techniques.Adsorption isotherms of indole,quinoline and toluene in octane were conducted at 25.0℃to explain the influence of toluene on nitrogen removal over NaY and YY.The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion,which led to an evident decline in BET surface area and pore volume of YY.Strong Br?nsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange.Though the specific surface area and pore volume of YY were much lower than those of NaY,YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene.In the presence of 20 vol%toluene,however,YY exhibited much higher adsorption capacities for indole and quinoline than NaY,especially in the case of quinoline.The improved toluene-tolerant of YY was ascribed to the strong acid–base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.

Redistributing Cu species in Cu-SSZ-13 zeolite as NH3-SCR catalyst via a simple ion-exchange

The nature and distribution of Cu species in Cu-SSZ-13 play a vital role in selective catalytic reduction of NO by NH3(NH3-SCR),but existing methods for adjusting the Cu distribution are complex and difficult to control.Herein,we report a simple and effective ion-exchange approach to regulate the Cu distribution in the one-pot synthesized Cu-SSZ-13 that possesses sufficient initial Cu species and thus provides a“natural environment”for adjusting Cu distribution precisely.By using this proposed strategy,a series of Cu-SSZ-13x zeolites with different Cu contents and distributions were obtained.It is shown that the dealumination of the as-synthesized Cu-SSZ-13 during the ion-exchange generates abundant vacant sites in the double six-membered-rings of the SSZ-13 zeolite for relocating Cu2+species and thus allows the redistribution of the Cu species.The catalytic results showed that the ion-exchanged Cu-SSZ-13 zeolites exhibit quite different catalytic performance in NH3-SCR reaction but superior to the parent counterpart.The structure–activity relationship analysis indicates that the redistribution of Cu species rather than other factors(e.g.,crystallinity,chemical composition,and porous structure)is responsible for the improved NH3-SCR performance and SO_(2) and H_(2)O resistance.Our work offers an effective method to precisely adjust the Cu distribution in preparing the industrial SCR catalysts.

Study on Removal of Trace Lead from Nickel Sulphate Solution by Ion-exchange Method

By comparing the adsorption capacity of several kinds of resins, D363 resin is regarded as the most suitable one for removing lead from nickel sulphate electrolyte. The effects of pH, temperature and contact time on exchange adsorption during removing trace lead from industrial nickel sulphate solution with D363 large pore weak alkali anion exchange resin are discussed. Optimum conditions of adsorption of lead from nickel electrolyte by D363 resin are at room temperature, pH 1 2, contact time 30 min.

Synthesis and Characterization of Ion-exchange Sulfonated Poly (ether sulfone)

N,N＇-Bis（3-hydroxyphenyl）-1,8,4,5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1,8,4,5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4,4＇-difluorodiphenylsulfone and disodium 3,3＇-disulfonate4,4＇-difluorodiphenylsulfone gave ion-exchange sulfonated poly（ether sulfone）. The structure of the title compound was characterized with H-NMR and its polymer was characterized with FT-IR.

Research on changes of hydrodynamics and ion-exchange adsorption in Brackish-Water Interface

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.

A RAPID METHOD TO DETERMINE DIFFUSION COEFFICIENTS OF COUNTER-IONS IN AN ION-EXCHANGE MEMBRANE

1 INTRODUCTIONRapid and precise methods to obtain the diffusion coefficients of counter-ions are im-portant for the characterization of ion exchange membranes.Many theoreticaldescriptions of ion transport in ion exchange membranes have been developed by usingthe principles of irreversible thermodynamics,or the Nernst-Planck equations.Fick’s law can also be used for the description of the transport of ions with equaldiffusivity.However,for counter-ions of different diffusivities,Nerst-Planck

Purification of a Choleragenoid by Ion-exchange Chromatography

Abstract: Choleragenoid was obtained in pure form by ultra-filteration and fractionation on cationexchange resin-phospho-cellulose column. The choleragenoid was highly pure as judged by the electrophoresis of isoelectric focusing,immunization and SDS-gel electrophoresis.The results of test are thesame as that of the standard choleragenoid.Keywoeds:choleragenoid; vibrio cholerae; purification;ion-exchange; chromatography

Synthesis and Characterization of Ion-exchange Copolyimide

A new diamine, disodium 4, 4-di(4-aminophenoxy)-3, 3-disulfonate-1, 1- diphenyl- ketone, was prepared from the nucleophilic substitution of disodium 4, 4- difluoro-3, 3-di- sulfonate-1, 1-diphenylketone and p-aminophenol. Polymerization of this diamine and 4, 4-diamino-1, 1- diphenyl ether with 3, 3, 4, 4-tetracarboxyl dianhydride-1, 1- diphenyl ketone gave ion-exchange copolyimide. The new diamine and its polyimide were characterized with 1H-NMR and FT-IR.

Soft actuator based on ion-exchange polymer-metal composite

Ion-exchange polymer-metal composite （IPMC） is a new electroactive material. It has large deformation and high force weight ratio in the presence of low voltage （〈1.5 V）. In this study a soft actuator known as artificial muscle based on IPMC was prepared. The IPMC actuator is composed of a perfluorinated ion-exchange membrane and platinum plated on both sides of the membrane by chemical means. Experiences and some key points are introduced in preparation of the IPMC. Electromechanical behaviors of the actuator are investigated, Factors related to the actuator performance are discussed.

DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION

On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%.

Thermoluminescent response of gamma irradiated Na^(+)–Cu^(+) ionexchanged silicate glass in large dose range

The introduction of metals into vitreous matrices is the origin of various interesting phenomena;in particular,the presence of copper ions in glass has been the subject of considerable research because of its numerous applications.The ion-exchange process is primarily used to introduce copper ions into glass matrices.The thermoluminescence(TL)of silicate glass was studied to evaluate its potential as gamma-sensitive material for dosimetric applications;the effect of copper doping on the thermoluminescent sensitivity was investigated using the Cu-Na ion-exchange technique for different concentrations and doping conditions,over a wide dose range of 10 mGy to 100 kGy.The results showed that Cu doping significantly improved the sensitivity of the glasses to gamma radiation.After the ion-exchange,two peaks appeared in the glow curves at approximately 175 and 230°C,respectively,which possibly originated from the Cu^(+) centers,along with a weak TL peak at around 320℃.We also attempted to explain the origin of the observed thermoluminescence by exploiting the Electron paramagnetic resonance(EPR)spectra.The results clearly show quenching of the TL emission with increasing copper concentrations.The present work indicates that the thermoluminescence response of these glasses to gamma rays can be reasonably measured in the range of 0.001-100 kGy.This study also facilitates the understanding of the basic TL mechanism in this glass system.

Hydrogeochemical characteristics and evolution of the aquifer systems of Gonghe Basin,Northern China

We present the first systematic hydrogeological analysis to grain insights on the evolution of the Gonghe Basin in North China. Two hundred and forty seven water samples were collected from the Gonghe East Basin, Gonghe West Basin and Chaka Basin. The three groundwater systems of Gonghe Basin from west to east display different geochemical signatures. Based on Na/Cl ratios and Langelier-Ludwig diagram, it is inferred that the groundwater recharge potential of the Gonghe East Basin is much prosperous than the other areas. The renewability of the aquifers in alluvial-proluvial fan of Wahonghe and Gonghe East Basin margin is much faster than in the other basins. The groundwater quality in Chaka Salt Lake,Shazhuyu and Qiabuqia River Valley plains is low due to strong evaporation and cation exchange. The groundwater quality of the phreatic aquifers in the Qiabuqia River Valley plain is further deteriorated by mixing of high-arsenic and high-mineralization water from the deep fault structures.

Treatment of drilling wastewater using a weakly basic resin

Macroporous weak basic anion exchanger （D301R） was used to remove organic substances from drilling wastewater. The effect of pH, temperature and contact time on adsorption behavior was investigated in batch experiments, which indicated that the COD （Chemical Oxygen Demand） removal ratio of drilling wastewater was approximately 90%, and the COD of treated wastewater was below 70 mg/L under appropriate operating conditions. A mixed liquor of NaOH and NaCI was selected as desorbent because of its better elution performance. The results of column dynamic adsorption and regeneration showed that the COD of wastewater could be efficiently removed by D301R resin, and the resin was easily regenerated by the selected desorbent.

Gain and Noise Figure of a Double-Pass Waveguide Amplifier Based on Er/Yb-Doped Phosphate Glass

A waveguide amplifier is fabricated by Ag^＋-Na^＋ two-step ion exchange on Er/Yb-doped phosphate glass. The spectroscopic performance of glass and the properties of channel waveguide are characterized. A double-pass configuration is adopted to measure the gain and noise figure （NF） of the waveguide amplifier, and the comparison of gain and NF for the single and double-pass configuration of the waveguide amplifier is presented. The results show that the double-pass configuration can make the gain increase from 8.8dB （net gain 2.2dB/cm） of the single-pass one to 14.6dB （net gain 3.65dB/cm） for small input power at 1534nm, and the NF are all lower than 5.5dB for both the configurations.

Removal of chloride from simulated acidic wastewater in the zinc production

The removal of chloride from the zinc electrolyte produced during hydrometallurgical zinc production is challenging. The ion-exchange method is a promising way to remove chloride if the resin washing wastewater can be recycled. This paper focuses on chloride removal from resin washing wastewater to enable its reuse. Various processing factors including the oxygen gas velocity, temperature, and reaction time were investigated systematically. The results show that the optimal conditions for dechlorination are an oxygen gas velocity of 0.5 L-min^-1, a reaction temperature of 80 ℃, and a reaction time of 30 min. A dechlorination efficiency of 80% with a residual chloride ion concentration less than 200 mg-L^-1 was achieved, which meets the requirements for the recycling of wastewater. The presence of manganese accelerates the dechlorination by forming a Mn^2+- MnO^2-MnO4^-Mn^2+ redox cycle. In this process, about 15 kg of the MnO2 and all of the zinc can be recovered from 100 m^3 wastewater, and the wastewater can be reused, which makes the ion-exchange method a promising technique for chloride removal.

Synthesis and antibacterial activity of new layered perovskite compounds,Ag_xNa_(2-x)La_2Ti_3O_(10)

Three kinds of new layered perovskite compounds with Ruddlesden-Popper （R-P） phase, AgrNa2-xLa2Ti3O10 （x = 0.2, 0.3 and 0.5）, were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution. The structures of the compounds were characterized by EDX and XRD, and their antibacterial activity and light-resistance property were evaluated. The results indicated that the molecular formula of AgxNa2-xLa2Ti3O10 （x = 0.2, 0.3 and 0.5） was confirmed, and that the crystalline structure of Na2La2Ti3O10 was not obviously affected by exchange of silver ion. The minimum inhibitory concentrations （MICs） of Ag0.3Na1.7La2Ti3O10 against Escherichia coli （E. coli）, Staphylococcus aureus （S. aureus） were 180 μg/mL and 240 μg/mL, respectively, while its discoloration was not observed after 24 h light ageing test.

Adsorption of Pb(Ⅱ)in Water by Niobate/Titanate Nanoflakes

A niobate/titanat nanoflakes(Nb/TiNFs)composite was synthesized via the hydrothermal method and used to remove Pb(Ⅱ)from water.XRD,TEM,and SEM results indicate that Nb/TiNFs appear as nanoflakes,of which the primary crystal phase is tri-titanate.Nb/TiNFs show rapid adsorption kinetics and the result fits well with the pseudo-second order model.The key mechanism of adsorption is ion-exchange between metal and-ONa/H.According to the Langmuir isotherm model,the maximum capacity of Pb(Ⅱ)is 488.323 mg·g^-1.The relatively low RL values indicate that Nb/TiNFs exhibit favorable adsorption of Pb(Ⅱ).Nb/TiNFs indicate high adsorption capacity over a broad pH range.Co-existing inorganic ions(Na+and Ca^2+)have a slight inhibition effect on adsorption,and HA moderately inhibits the adsorption of Pb(Ⅱ)on Nb/TiNFs.Because of the simple method of synthesis and high removal efficiency for heavy metals,Nb/TiNFs are a promising material in remediation of heavy metal polluted water.