Acid Cation Exchange Research Articles

Ion exchanger BIONA 312 as a component of soils polluted with nickel in cultivation of cucumber (Cucumis sativus L.)

The objective of the studies undertaken was to assess the possibility of ion exchange substrate BIONA 312 use for nickel bioavailability limitation in cucumber (<i>Cucumis sativus</i> L.) 'Hermes'cv. as determined on the ground of chlorophyll and Ni content. BIONA 312, regarding the chemical composition, is a mixture of strongly acid cation exchanger KU-2x8 and polyfunctional weakly alkaline anion exchanger EDE-10P. The experiment was differentiated in regard to nickel and ion exchanger content. The following doses of Ni (in the form of NiSO<sub>4</sub>) were introduced: 0,30 or 75mg Ni·dm<sup>-3</sup> of the substrate. BIONA 312 was added to the medium in the following doses: O,2 or 5% of substrate volume. Together with Ni dose increase in the medium there was recorded a significant increase of this metal concentration in the cucumber biomass. Nickel in the amount 30 mg dm<sup>-3</sup> did not affect considerably the changes in any of chlorophyll form, but a dose 75mg Ni·dm<sup>-3</sup> has caused a significant decrease in chlorophyll "a" concentration in cucumber leaves. Simultaneously with the increase in the nickel content in the nutritive environment the decrease in the value of organic mass productivity coefficient was observed. The introduction of 5% ion exchange substrate BIONA 312 into the medium containing nickel in the amount 30 or 75 mg·dm<sup>-3</sup> induced a significant growth of the studied chlorophyll fractions in the cucumber leaves. BIONA 312 introduced to the environment contaminated with nickel in the amount of 30 or 75 mg·dm<sup>-3</sup> has significantly reduced Ni content in the cucumber biomass simultaneously increasing participation of roots in organic mass production. More efficient for the reduction of harmful Ni effect on the cucumber plants turned out to be introduction of ionite sorbent BIONA 312 at the dosage 5% than 2%.

Removal and Recovery of Chromium from Solutions Simulating Tannery Wastewater by Strong Acid Cation Exchanger

The process in this study was conducted on removal of chromium(III) in a solution simulating a typical spent chrome tanning bath by the resin having matrix of styrene‐divinylbenzene‐based macroporous sulphonate, Amberjet 1200Na. The column experiments were carried out with the bed volumes of the resin as 751 mL and 1016 mL for different installation systems of the laboratory‐scale pilot plant. The feeding solutions in the bed volumes of 200 and 190 were used for each installation system. The regeneration behaviour of the resin was determined by using reverse regeneration procedure with the solution of hydrogen peroxide in alkaline. The regeneration kinetics of the exhausted resin was examined with a range of the solutions having different concentration series of the alkaline hydrogen peroxide. The solutions of the basic chromium sulphate were recycled for each installation system following the regeneration cycles. The chromium ions in effluent were quantitatively eluted, and satisfactory removal of chromium(III) and recovery of chromium(VI) were achieved.

Techno-Economic Study of Copper Removal from Acid Mine Drainage by Ion-Exchange Technique

Economic feasibility has been studied for removal of copper from acid mine drainage wastewater by ion exchange. Ion exchange method has been used for removal of copper from industrial wastewaters. Experiments were conducted using packed bed column. The present study were carried out for solutions with concentrations of 100 mg/lit to 200 mg/lit and pH values of 3 to 6, using Indion 730, strong acid cation exchange resin. Under the present operating conditions considered, the strong acid type resin was found to bring down initial copper content by almost 46-56 % and at pH 5, 60% of copper removal for 200 mg/lit of initial concentration was found. The techno economic feasibility was then studied and the rate of return found to be 21% which is economically viable.

Prevention of scale formation and saline wastewater discharge during district heating systems operation

The factors, determining the intensity of scale formation in district heating systems, were considered. For closed systems scale formation intensity is defined by the carbonate index, which is standardized by the rules of technical operation depending on the temperature of water heating. For open systems, which have direct contact with the atmosphere (circulating water cooling systems), the intensity of salts accumulation is proportional to the product of calcium hardness and square alkalinity of water. The equations were derived, which allow determining the required load by absorbed cations on weakly acidic cation exchange resins and, accordingly, the required amount of filters media. Replacing traditional technology of preparation of make-up water of heating systems using sodium cycling method by water treatment in filters, loaded by weakly acidic cation exchange resin with further decarbonization, allows reducing reagent consumption by 8 times and significant reduction of saline wastewater discharge into surface water reservoirs. The results of studying the process of softening waste regeneration solutions by soda and lime are given. Reduction of wastewater hardness to the values<3mg∙ekv/dm3 requires precise dosing of reagents.

Integration of ion exchange and electrodeionization as a new approach for the continuous treatment of hexavalent chromium wastewater

Mining and electroplating wastewaters contain many harmful ions, which are discharged into waterways and water bodies and cause significant environmental damage. Hexavalent chromium (Cr(VI)) is an ion that is commonly present in these effluents, which has been proven as toxic to humans. In the present work, continuous ion exchange and electrodeionization are proposed as a new hybrid technology for the effective treatment of Cr(VI) wastewater as well as the recovery of chromium ions. We have systemically studied a strong basic macroreticular anion exchange resin (Amberlite® IRA900) for the removal of Cr(VI). The ion exchange isotherm and kinetics of the resin were determined, showing that the IRA900 anionic ion exchange resin has a high capacity for ion exchange with hexavalent chromium (116mg Cr(VI) per gram of resin). When the anionic resin was combined with a strong acidic macroreticular cation exchange resin (Amberlite® 200C) and employed in continuous electrodeionization, over 98.5% of Cr(VI) was continuously removed from the dilute compartment with an energy consumption of less than 0.07kWh/m3, while Cr(VI) was recovered in the concentrate compartment.

Direct Hydration of β-Caryophyllene

This study of β-caryophyllene hydration to produce β-caryophyllene alcohol was carried out catalyzed by strong acidic cation exchange resin NKC-9. The effects of different parameters such as agitation speed, catalyst type, catalyst loading, mass ratio of the reactants, temperature, and reaction time on the conversion of β-caryophyllene and yield of β-caryophyllene alcohol in a stirred-tank reactor have been investigated to obtain the optimal conditions. Under the optimal conditions (catalyst loading 20%(w/w), nβ-caryophyllene/nwater 1/1, reaction temperature 363.15 K, reaction time 30–40 min), the experiment was then carried out in a pilot-scale stirred tank reactor and in a novel pilot-scale jet reactor respectively to achieve excellent performance. The β-caryophyllene alcohol has been purified by rectifying column and recrystallized. A pseudohomogeneous (PH) model was used to correlate the kinetic data in the temperature range from 333.15 to 363.15 K. The estimated kinetic parameters make the calculated...

Studies on adsorptive removal of radioactive cobalt from alkaline waste generated in sodium cooled fast breeder reactors

The removal of radioactive cobalt from alkaline waste containing sodium has been studied in batch process using two different inorganic compounds (a) hydrous manganese oxide (HMO), and (b) copper hexa-ferrocyanide (CFC) and compared with a strongly acidic cation exchange resin (Dowex50W×8). The percentage removal of cobalt was examined by varying experimental conditions, viz. pH of the solution, contact time and interfering ions. The studies showed that HMO can be used as an efficient adsorbent for the removal of cobalt from sodium containing wastes.

Concentration and selective fractionation of an antihypertensive peptide from an alfalfa white proteins hydrolysate by mixed ion-exchange centrifugal partition chromatography

This article reports a promising use of the mixed ion-exchange centrifugal partition chromatography (MIXCPC) technique in the field of downstream processes. A complex alfalfa white protein concentrate hydrolysate (AWPC hydrolysate) showing anti-hypertensive properties was successfully fractionated by MIXCPC to yield a l-valyl-l-tryptophan (VW) enriched fraction in one run. This dipeptide shows an interesting anti-angiotensin converting enzyme (anti-ACE) activity. An analytical method based on RP-LC/MS-MS was developed to quantify the target VW peptide in both the starting material and the enriched fractions. The best results for the MIXCPC fractionation were obtained by the combined use of the quaternary biphasic solvent system, methyl-tert-butylether/acetonitrile/n-butanol/water (2:1:2:5, v/v) in the descending mode, of the lipophilic di(2-ethylhexyl)phosphoric acid (DEHPA) cation-exchanger with an exchanger (DEHPA)/peptides ratio of 15, and of two displacers: calcium chloride and hydrochloric acid. The complexity of the starting material involved the selectivity optimization by splitting the stationary phase into two sections that differed by their triethylamine concentration. From 1g of AWPC hydrolysate containing 0.26% of VW, 30.7mg of a VW enriched fraction were recovered with a purity of 10.9%, corresponding to a purification factor of 41 and a recovery of 97%.

Versatility of cinchona-based zwitterionic chiral stationary phases: Enantiomer and diastereomer separations of non-protected oligopeptides utilizing a multi-modal chiral recognition mechanism

Cinchona alkaloid-based zwitterionic chiral stationary phases with diverse sulfonic acid cation exchanger groups were applied for enantiomer separations of small homochiral oligopeptides (all-l/all-d Ala-n, Val-n, Phe-n) using slightly acidic polar-organic mobile phase conditions which facilitated the ionization of ion exchanger sites of the chiral selectors as well as promoting zwitterion formation of the chiral selectands. Our studies focused on retention factors and selectivity as the main chromatographic parameters illustrating selector–selectand interactions. The results confirmed that bulky, aromatic side chains such as the benzyl group of Phe are analyte-inherent structural features promoting enantiorecognition. Regarding the zwitterionic selectors, a flexible spacer between the anion exchanger-carbamoyl and the cation exchanger sites was found to enhance stereoselectivity toward bulky and aromatic peptides while a rigid cation exchanger moiety contributed favorably to enantiomer distinction of peptides with small, aliphatic side chains. The investigations included all 28 stereoisomers of Phe-2 through Phe-4 to demonstrate the applicability of zwitterionic chiral stationary phases for the separation of sequential stereoisomers. Selectivity was shown to be governed by the Cinchona alkaloid motif but heavily dependent on effective hydrogen bonding between the carbamoyl motif and the amide groups of the peptide backbone. Contrary to previous studies on enantioselectivity which found pseudo-enantiomeric behavior of quinine and quinidine-based CSPs, in peptide stereoisomer separations CSPs based on quinidine undeniably performed better.

Microwave Assist Synthesis Methyl Ferulate through a Cationic Exchange Resin Catalysis Routine

Methyl ferulate was synthesized by methanol and ferulic acid with strongly acidic cation exchange resin as catalyst under microwave irradiation. The effect of catalyst activity was investigate by single factor experiment. Amount of catalyst, microwave treatment time, microwave output power and methanlo/ ferulic acid ratio were investigate by single factor experiment and orthogonal experiments. The optimal reaction conditions were ferulic acid being 0.1mol, molar radio of ethanol to ferulic acid being 5:1, mass percent of resin being 30％ of the reagent, microwave power being 300W, reaction time being 25 min. The yield of product was 81.2％ under the potimal conditions. The catalytic characteristics of regenerated catalyst were stable and the yield of product may keep greater than 76% after the 732# resin used five times.

Mass transport in a boundary layer and in an ion exchange membrane: Mechanism of concentration polarization and water dissociation

In an unforced flowing NaCl solution in bulk, gravitational or electro convection supplies ions from bulk toward the membrane surface through a boundary layer. In a boundary layer formed on an anion exchange membrane, the convection converts to migration and diffusion and carries an electric current. In a boundary layer formed on a cation exchange membrane, the convection converts to migration and carry an electric current. In a forced flowing solution in bulk, the boundary layer thickness is reduced and gravitation or electro convection is disappeared. An electric current is carried by diffusion and migration on the anion exchange membrane and by migration on the cation exchange membrane. Ion transport in a boundary layer on the cation exchange membrane immersed in a NaCl solution is more restricted comparing to the phenomenon on the anion exchange membrane. This is due to lower counter-ion mobility in the boundary layer and the restricted water dissociation reaction in the membrane. The water dissociation reaction is generated in an ion exchange membrane and promoted due to the increased forward reaction rate constant. However, the current efficiency for the water dissociation reaction is generally low. The intensity of the water dissociation is more suppressed in the strong acid cation exchange membrane comparing to the phenomenon in the strong base anion exchange membrane due to lower forward reaction rate constant in the cation exchange membrane. In the strong acid cation exchange membrane, the intensity of electric potential is larger than the values in the strong base anion exchange membrane. Accordingly, the stronger repulsive force is developed between ion exchange groups (SO3• groups) and co-ions (OH− ions) in the cation exchange membrane, and the water dissociation reaction is suppressed. In the strong base anion exchange membrane, the repulsive force between ion exchange groups (N+(CH3)3 groups) and co-ions (H+ ions) is relatively low, and the water dissociation reaction is not suppressed. Violent water dissociation is generated in metallic hydroxides precipitated on the desalting surface of the cation exchange membrane. This phenomenon is caused by a catalytic effect of metallic hydroxides. Such violent water dissociation does not occur on the anion exchange membrane.

Sorption-spectroscopy determination of zirconium on a PANV-KU-2 fibrous ion exchanger using Arsenazo III

The sorption and complexation of zirconium with Arsenazo III have been studied on a polyacry-lonitrile fibrous material filled with strongly acidic KU-2 cation exchanger in strongly acidic media. The optimal conditions have been chosen for the sorption-spectrophotometric and test determination of zirconium by diffuse reflection spectroscopy or visual testing. The limit of zirconium detection is 0.02 μg/mL. The procedure was tested in the analysis of model solutions of ammonium molybdate and vanadate and copper chloride using the standard addition method.

Modified mesoporous clay adsorbent for adsorption isotherm and kinetics of methylene blue

Adsorptive uptake of methylene blue (MB) by both raw and modified Ball clay (MBC) were investigated through batch adsorption experiment. Modification of the raw clay was done by acid treatment, cation exchange and calcination; the raw and modified clays were molded into beads and freeze dried. Brunauer Emmett Teller (BET), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Fourier transformed infrared spectroscopy (FTIR) analysis were carried out on both clays. The mesoporous modified Ball clay (MBC) had percent increase of adsorption capacity and surface area of 188.60% and 820%, respectively than the raw Ball clay (RBC). Langmuir, Freundlich and Redlich–Peterson models were used to obtain isotherm parameters. Pseudo-second-order kinetic model described the adsorption processes which were more favorable at higher pH. Increase in temperature from 30 to 50°C of MB adsorption on both RBC and MBC increased the degree of dispersion and the process was found to be physiosorptive, endothermic and spontaneous for MBC but non-spontaneous for RBC; this was obtained from the thermodynamic studies. The results showed that MBC can be used adequately to adsorb MB more efficiently than RBC.

Synthesis, characterization, thermal and dielectric properties of pure and cadmium doped calcium hydrogen phosphate

The synthesis of pure and cadmium doped calcium hydrogen phosphate as single crystal has been accomplished by a room temperature solution growth technique viz., silica gel technique. Silica gel obtained from sodium metasilicate with a strongly acidic cation exchanger in the H-form, was used for crystal growth experiments. The nature of the grown material was established by powder X-ray diffraction (PXRD) studies, whereas from single crystal X-ray diffraction (SXRD) the crystal system comes out to be monoclinic. The stoichiometry of the grown composition was established by energy dispersive X-ray analysis (EDAX). Fourier transform infrared spectroscopic (FTIR) studies signifies the presence of phosphate (PO4)2− group and water of crystallization. Thermo gravimetrical analysis and investigations of dielectric properties were undertaken to study the thermal stability, dielectric constant and transition temperature of the grown material. Dielectric studies suggest that there is a shift in the value of transition temperature (Tc) thereby indicating relaxor behaviour of the material.

Effect of Polacrilin Potassium as Disintegrant on Bioavailability of Diclofenac Potassium in Tablets : a Technical Note

Polacrilin potassium is an ion exchange resin used in oral pharmaceutical formulations as a tablet disintegrant. It is a weakly acidic cation exchange resin. Chemically, it is a partial potassium salt of a copolymer of methacrylic acid with divinyl benzene. It ionizes to an anionic polymer chain and potassium cations. It was hypothesized that polacrilin potassium may be able to improve the permeability of anionic drugs according to the Donnan membrane phenomenon. The effect of polacrilin potassium on the permeability of diclofenac potassium, used as a model anionic drug, was tested in vitro using diffusion cells and in vivo by monitoring serum levels in rats. The amount of drug permeated across a dialysis membrane in vitro was significantly more in the presence of polacrilin potassium. Significant improvement was found in the extent of drug absorption in vivo. It could be concluded that polacrilin potassium may be used as a high-functionality excipient for improving the bioavailability of anionic drugs having poor gastrointestinal permeability.

Use of Adsorbed Solution theory to model competitive and co-operative sorption on elastic ion exchange resins

An Adsorbed Solution theory which takes into account non-idealities in both the adsorbed and the liquid phase was applied for the prediction of multi-component adsorption equilibria based on single component and binary mixture data. A novel non-iterative solution method was applied for the solution of the set of partly implicit model equations. The Pitzer activity coefficient model was used for the liquid phase and an empirical model for the adsorbed phase activity coefficients. Separation of concentrated acid lignocellulosic hydrolysates on an elastic strong acid cation exchange resin was used as a test system. The application is relevant in biorefineries when polysaccharides in wood are hydrolyzed to monosaccharides using concentrated sulfuric acid.It was found that the novel solution method for the equilibrium model can be applied successfully for complex multi-component systems; it is fast and easy to implement. The predictions of the thermodynamic model were validated with dynamic column experiments (pulse injections and loading/elution curves). Hereby, in the column mass balances, porosity fluctuations were taken explicitly into account. Satisfactory correlation between the calculated and experimental results was obtained. It was observed that the predictions of the model can be quite sensitive with respect to even minor inaccuracies in the calculated multi-component adsorption isotherms.

ChemInform Abstract: Solvent‐Free Synthesis and Antibacterial Studies of Some Quinolinones.

AbstractThe strongly acidic cation exchange resin Amberlite SR1L in Na+ form catalyzes the microwave‐promoted condensation to quinolones (III) as well as a subsequent microwave‐assisted N‐alkylation reaction.

Effect of the porous structure of polymer on the kinetics of Ni2+ exchange on hybrid inorganic-organic ionites

Hybrid organic-inorganic ion exchangers are obtained by incorporating amorphous zirconium hydrophosphate into the gel of strong acidic cation exchange resin. Hybrid organic-inorganic ion exchangers are obtained by modifying strong acidic cation exchange resin with amorphous zirconium hydrophosphate. The synthesized materials are studied by standard porometry contact. It is found that raising the inorganic component content to 34 wt % diminishes the microporosity of the samples and simultaneously enhances the of meso- and macropore volume. Experiments establish that modification of a polymer matrix lowers the self-diffusion coefficient of Ni2+ from 8.1 × 10−12 to 2.4 × 10−12–4.1 × 10−12 m2 s−1; nevertheless, an inorganic ion exchanger minimizes the inhibitory effect of co-ions on the Ni2+ → H+ exchange rate. One possible mechanism for of filling of the matrix by with particles of zirconium hydrophosphate is discussed.

Enhanced conductivity detection of common inorganic anions in electrostatic ion chromatography using water eluent.

To enhance the conductivity detection sensitivity of common anions (Na-anions) in electrostatic ion chromatography (EIC) by elution with water, a conductivity enhancement column packed with strong acid cation exchange resin in the H-form was inserted between an octadecyl silane (ODS)-silica separation column modified with zwitterionic surfactant (CHAPS: 3-{(3-cholamidopropyl)-dimethylammonio} propanesulfonate) and a conductivity detector. Specifically, the Na-anion pairing is converted to H-anion pairing after the EIC separation and then detected sensitively by the conductivity detector. The effects of conductivity enhancement and suppression in the EIC by the enhanced conductivity detection were characterized for the common strong acid anions such as SO4(2-), Cl(-), NO3(-), I(-) and ClO4(-) and weak acid anions such as F(-), NO2(-), HCOO(-), CH3COO(-) and HCO3(-). For the conductivity enhancement effect in the EIC, it is found that the conductivity of measured for all strong acid anions (Na-anions) was enhanced according to the theoretical conductivity predicted for H-anions and that of the measured for weak acid anions was suppressed depending on their pKa of H-anions. For the calibration linearity in the EIC, the strong acid anions were linear (r2 = 0.99 - 1.00) because the degree of dissociation is almost 1.0 over all the concentration range and that of the weak acid anions was non-linear because the degree of dissociation decreased by increasing the concentration of the weak acid anions. In conclusion, the EIC by enhanced conductivity detection was recognized to be useful only for the strong acid anions in terms of conductivity detection and calibration linearity.

An evaluation of a hybrid ion exchange electrodialysis process in the recovery of heavy metals from simulated dilute industrial wastewater

Hybrid ion exchange electrodialysis, also called electrodeionization (IXED), is a technology in which a conventional ion exchange (IX) is combined with electrodialysis (ED) to intensify mass transfer and to increase the limiting current density and therefore to carry out the treatment process more effectively. It allows the purification of metal-containing waters, as well as the production of concentrated metal salt solutions, which could be recycled. The objective of this paper was to investigate the ability of the IXED technique for the treatment of acidified copper sulphate solutions simulating rinsing water of copper plating lines. A single-stage IXED process at lab-scale with a small bed of ion exchanger resin with a uniform composition was evaluated, and the treatment performance of the process was thoroughly investigated. The IXED stack was assembled as a bed layered with the ion exchanger resin (strong acid cation-exchange Dowex™) and inert materials. The stack configuration was designed to prevent a non-uniform distribution of the current in the bed and to allow faster establishment of steady-state in the cell for IXED operation. The influence of operating conditions (e.g. ion exchanger resin with a cross-linking degree from 2 to 8% DVB, and current density) on IXED performance was examined. A response surface methodology (RSM) was used to evaluate the effects of the processing parameters of IXED on (i) the abatement yield of the metal cation, which is a fundamental purification parameter and an excellent indicator of the extent of IXED, (ii) the current yield or the efficiency of copper transport induced by the electrical field and (iii) the energy consumption. The experimental results showed that the performance at steady-state of the IXED operation with a layered bed remained modest, because of the small dimension of the bed and notably the current efficiency varied from 25 to 47% depending on the conditions applied. The feasibility of using the IXED in operations for removal of heavy metals from moderately dilute rinsing waters was successfully demonstrated.