Ion-exchange Capability Research Articles

Synthesis and Thermal Stability of Melamine-Formaldehyde-Nitro Aniline Ion-Exchange Resin

A series of resins was synthesized and analyzed for selective ion-exchange nature for some metals. Substituted aniline was reacted with formaldehyde, melamine. For the synthesis of ion-exchange resins, sulfuric acid was used as a catalyst. These resins were characterized by elemental analysis and studied antimicrobial activities. Synthesized Resin shows ion exchange capability and moderate activity against microbial. Ion exchange resin also showed reusability and stability at an elevated temperature.

PW051 The effect of methoxy poiyethilenglicol -epoietin beta in patiens chronic heart failure with anemic syndrome

A new class of hybrid nanocomposite, poly(aniline-co-o-toluidine)(PANI-Co-OT) tungstomolybdate (TM) was prepared by sol–gel method. The physico-chemical characterization was carried out by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultra Violet Spectroscopy (UV–vis) and simultaneous Thermogravimetric Analysis (TGA) studies. The ion-exchange capacity, distribution studies were also carried out to understand the ion-exchange capabilities. It is highly semiconducting nature in the range of 1.6155 × 10− 1–3.0786 × 10− 1 S/cm. Based on distribution studies, composite was found highly selective for Pb(II) heavy metal ions. Ion-selective membrane electrode was designed for the determination of Pb(ІІ) ions in solutions. The analytical utility of this membrane was established by employing it as an indicator electrode.

An electroactive porous network from covalent metal–dithiolene links

Simple synthesis and versatile functions: by directly reacting a triphenylene hexathiol molecule (HTT) with PtCl2, a covalent metal-organic framework (CMOF) has been prepared that features substantial porosity, redox activity and ion exchange capability.

Efficacy of Supplemental Natural Zeolite in Broiler Chickens Subjected to Dietary Calcium Deficiency

Natural zeolite, or sodium aluminosilicate, influences calcium (Ca) and phosphorus (P) utilisation in chicks. A 2×2 factorial arrangement of treatments was used to investigate the effect of dietary Ca (recommended and below recommended levels) and zeolite (0 and 0.8%) on growth, plasma, tibia and faeces in chickens from 1 to 42 days of age. Zeolite supplementation did not affect overall body weight (BW) gain, feed intake (FI) or feed conversion ratio (FCR) of broiler chickens (P>0.05). Overall mortality of zeolite-fed chickens was lower than in untreated ones (P<0.01). Reduction of dietary Ca of approximately 10 to 18% decreased (P<0.05) BW at 14 and 42 days of age in association with reduced FI, but overall FCR was unchanged. Serum protein and sodium constituents were reduced in birds fed zeolite (P<0.05). Decreasing dietary Ca level increased (P<0.01) serum, total protein and glucose concentrations, but decreased Ca level. Zeolite decreased bone ash in birds fed a Ca-deficient diet while increased faecal excretion of ash, Ca, P and aluminum. However, zeolite increased tibia weight (P<0.05) and thickness (P<0.01). No significant response (P>0.05) in relative weight and gross lesion scores of liver or footpad lesion scores was found related to changes in dietary regimens.The results of the present study do not corroborate the hypothesis that the effectiveness of zeolite may be improved in Ca-deficient diets in association with its ion exchange capability.

In situ synthesis of metal/polymer nanocomposite thin films on glass substrates by using highly cross-linked polymer matrices with tailorable ion exchange capabilities

We describe the use of ion-exchangeable, highly cross-linked polymer films as a matrix for the synthesis of nanocomposite thin films and patterns with embedded Cu and Ni nanoparticles. We have successfully controlled the size of metal nanoparticles and thus optical and magnetic properties of the films by varying the initial amount of doped metal ions.

Ion Exchangers as Adsorbents for Removing Metals From Aquatic Media

A polyaniline-based composite cation-exchange material was synthesized by way of sol-gel method and studied to explore its analytical and environmental applications. It was characterized by using instrumental analyses [Fourier transform infrared (spectrometer), X-ray, thermogravimetric analysis/differential thermal analysis, standard electron microscopy, and transmission electron microscopy]. Physicochemical studies, such as ion-exchange capacity, pH titrations, and chemical stability, along with effect of eluent concentration and elution, were also performed to exploit the ion-exchange capabilities. pH titration studies showed that the material presents monofunctional strong cation-exchange behavior. This nanocomposite material is semicrystalline in nature and exhibits improved thermal and chemical stability. The partition coefficient studies of different metal ions in the material were performed in demineralised water and different surfactant media, and it was found to be selective for Pb(II) and Hg(II) ions. To exploit the usefulness of the material as an adsorbent, some important quantitative binary separations of metal ions were performed on polyaniline Zr(IV) molybdophosphate columns. This composite cation exchanger can be applied for the treatment of polluted water to remove heavy metals.

Applied poly(2-methoxy aniline) Sn(II)silicate carbon nanotubes composite: Synthesis, characterization, structure–property relationships and applications

A new class hybrid poly(2-methoxy aniline) Sn(II)silicate carbon nanotubes composite was synthesized by sol–gel method. The physico-chemical characterization was carried out by Scanning Electron micrograph, X-ray Diffraction, Fourier Transform Infrared, Ultraviolet–Visible Spectroscopy and simultaneous Thermo Gravimetric Analysis. The ion-exchange studies were also carried out to understand the ion-exchange capabilities. The dc electrical conductivity studies reviles its highly conducting nature in the range of 2–3−2Scm−1. On the basis of distribution studies it was found highly selective for Hg2+. Due to selectivity of the composite, ion selective membrane was prepared and employed it as an indicator electrode in potentiometric titrations.

Ionically modified magnetic nanomaterials for arsenic and chromium removal from water

We describe a method for the removal of arsenic and chromium contaminants from water by using ionically modified magnetic nanoparticles (PPhSi-MNPs). We synthesized and covalently attached a cationic ligand: phosphonium-silane (PPhSi), onto iron oxide magnetic nanoparticles. We exploit the ion-exchange capability of the phosphonium ligand for the removal of the metal ions from water and superparamagnetic nature of iron oxide for physical separation of the sorbent materials for recovery and regeneration. Chemical and physical properties of the phosphonium-coated MNPs are investigated by FTIR, TEM, XPS, EDX, XRD and zeta potential. The highest As(V) and Cr(VI) adsorption efficiency is observed at pH 3. The adsorption of As(V) and Cr(VI) on PPhSi-MNPs is not affected to any considerable extent by the presence of coexisting anions such as chloride, nitrate, and sulfate except phosphate. The adsorption data are best fitted with the Langmuir isotherm model and a pseudo-second-order kinetic model is proposed. Based on the zeta-potential and chemical analyses of the adsorbent surface, we propose that a synergy of electrostatic interaction and ion-exchange between anionic metals and the cation-modified magnetic nanoparticles allow highly efficient removal of the pollutants. A simple pH-triggered desorption and regeneration of the adsorbent is also presented. With adsorption capacities for arsenic (50.5mg/g) and chromium (35.2mg/g), coupled with facile magnetic separation, this nanoadsorbent can be an attractive material for the removal of several anionic metal species from water.

Study of the Adsorbent-Adsorbate Interactions from Cd(II) and Pb(II) Adsorption on Activated Carbon and Activated Carbon Fiber

The adsorption characteristics of Cd(II) and Pb(II) in aqueous solution using granular activated carbon (GAC), activated carbon fiber (ACF), modified ACF (NaACF), and a mixture of GAC and NaACF (GAC/NaACF) have been studied. The surface properties, such as morphology, surface functional groups, and composition of various adsorbents were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The specific surface area, total pore volume, and pore size distribution were investigated using nitrogen adsorption, Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) methods. In this study, NaACF showed a high adsorption capacity and rate for heavy metal ions due to the improvement of its ion-exchange capabilities by additional oxygen functional groups. Moreover, the GAC and NaACF mixture was used as an adsorbent to determine the adsorbent-adsorbate interaction in the presence of two competitive adsorbents.

Enhanced hydrolytic stability of sulfonated polyimide ionomers using bis(naphthalic anhydrides) with low electron affinity

In the pursuit of hydrolytically stable sulfonated polyimide (SPI) membranes as promising candidates for proton exchange membranes, usable at elevated temperature, a series of novel SPI ionomers based on the low electron affinity bis(naphthalic anhydrides), 4,4′-sulfide-bis(naphthalic anhydride) (SBNA) and benzophenone-4,4′-bis(4-thio-1,8-naphthalic anhydride) (BPBTNA), were prepared. Tough, flexible, and transparent membranes were obtained from these polymers, although their inherent viscosities ranged from 0.41 to 0.59 dL g−1. The SPI membranes were thermally stable with the decomposition of sulfonic acid groups over 300 °C, and exhibited good mechanical properties with 65 MPa of tensile strength at 25 °C and 50% RH. The proton conductivities of the SPI membranes increases with increasing temperature and ion exchange capability (IEC), and the S–O(80) with 2.23 mequiv. g−1 of IEC showed a higher proton conductivity than Nafion® 212 at 100% RH. For the high IEC membranes, microscopic analyses revealed the hydrophilic clusters were well-dispersed and connected to each other. The accelerated water stability tests demonstrated that the SPI ionomers based on SBNA and BPBTNA maintained a high mechanical strength after being aged in water for 24 h at 140 °C, which was much more stable than the SPI membranes based on 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTDA). The improved hydrolytic stability of polymers could be well correlated with the results of the electron affinity (Ea) of the dianhydride calculated by the theoretical calculation. This investigation illustrated that this strategy will benefit the further development of hydrolytically stable SPIs applied to high temperature PEFCs.

Analyzing freely dissolved concentrations of cationic surfactant utilizing ion-exchange capability of polyacrylate coated solid-phase microextraction fibers

A 7-μm polyacrylate (PA) coated fiber was successfully employed to determine freely dissolved concentrations of cationic surfactants by solid-phase microextraction (SPME) and utilizing the capability of the PA-coating to sorb organic cations via ion-exchange at carboxylic groups. Measured fiber–water partitioning coefficients (Kfw) were constant below a fiber loading of 2mmol per liter polyacrylate, allowing for simple and accurate analysis in a concentration range that is relevant from a risk assessment point of view. Ion-exchange was confirmed to be the main sorption mechanism because of a decreasing Kfw with either higher CaCl2 concentrations or lower pH, and maximum fiber uptake at the polyacrylate cation-exchange capacity (CEC, at 30mmol/L PA). Fiber–water sorption isotherms were established in various aqueous media in toxicological relevant concentrations. The developed SPME method has a high potential for application in ecotoxicological studies, as demonstrated in sorption studies with humic acid in different electrolyte solutions at aqueous concentrations down to the sub nM range. Cationic surfactant sorption affinities for humic acid also depend on medium composition but are orders of magnitude higher than to the PA fiber on a sorbent weight basis.

Synthesis and characterization of novel cation exchange adsorbent for the treatment of real samples for metal ions

Poly-o-toluidine based novel organic–inorganic hybrid ion exchange adsorbent has been synthesized via sol–gel process and characterized by FTIR, XRD, SEM, TEM and TGA studies. The physico-chemical properties such as ion exchange capacity, pH titration curves, chemical stability along with effect of eluent concentration and elution behavior were also carried out to exploit the ion-exchange capabilities. SEM analysis exposed that after binding inorganic precipitate with poly-o-toluidine the morphology of the composite material has been changed which is semicrystalline. The pH titration studies prove that material shows bifunctional strong cation exchange behavior. On the basis of chemical stability it can be successfully used in a number of solvent systems up to the concentration of 2molL−1. Partition coefficients studies (Kd values) of divers metal ions were performed in some pure and mixed solvent systems by using this material. On the basis differential behavior of the material towards different metal ions it has been concluded to be selective for Ca(II), Sr(II), Zn(II), Cd(II) and Zr(IV) ions. To exploit the usefulness of the material as an adsorbent, some important quantitative binary separations of important metal ions were performed on poly-o-toluidineZr(IV)iodate columns. On the basis of good uptake capacity this composite ion exchange adsorbent has been successfully used for removal and recovery Zr(IV) and Cd(II) ions from real samples and synthetic mixture.

Effect of dopants on the adsorbing performance of polypyrrole/graphite electrodes for capacitive deionization process

Polypyrrole/graphite electrodes (PPy/G-Cl, PPy/G-p-TS and PPy/G-DBS) were synthesized by electrochemical polymerization process. The three type of electrodes were then used as anode respectively to study the effect of dopants on the adsorbing performance of PPy/G electrodes in capacitive deionization process. The morphology, thickness, conductivity of PPy layers and the surface area of the PPy/G electrodes were characterized and tested respectively, all of which depend on the type of dopants. The electrochemical impedance spectroscopies infer that the adsorbing processes of the PPy/G electrodes are controlled by Warburg diffusion. Also, the PPy/G-Cl and PPy/G-p-TS electrodes show better conductivity than the PPy/G-DBS electrode in CDI cells. The ion exchange capability of the PPy layers was measured by an electrochemical quartz crystal microbalance (EQCM), which proves that the ion exchange capability of the PPy layers is in the order of: PPy-p-TS>PPy-Cl>PPy-DBS. The results of adsorbing experiments indicate that the specific adsorption capacities of PPy/G electrodes to Cl− vary with the type of dopants and follow the order of: PPy/G-p-TS>PPy/G-Cl>PPy/G-DBS. Further, it can be obtained that dopants dominate the electrochemically switchable ion exchange (ESIE), and the specific adsorption capacities of the PPy/G electrodes are mainly determined by the ESIE.

Ion-exchange studies of ‘organic–inorganic’ nano-composite cation-exchanger: Poly-o-anisidine Sn(IV) tungstate and its analytical application for the separations of toxic metals

The separation of Hg(II) from aqueous solutions was studied using Poly-o-anisidine Sn(IV) tungstate nano-composite cation exchanger. This nano-composite material was synthesized via sol–gel mixing of Poly-o-anisidine with the inorganic precipitate of Sn(IV) tungstate, providing a new class of organic–inorganic nano-composite cation exchanger with good ion-exchange capacity, better chemical and thermal stability than most of the Poly-o-anisidine based exchanger reported so far. The ion-exchange capacity and ion-exchange behaviors of the nano-composite were also carried out to understand the ion-exchange capabilities. Its selectivity was examined by achieving some important binary and tertiary separations of metal cations on its column indicating its utility in environmental pollution control. This new exchanger was successfully applied for quantitative determination and separation of Hg(II) from a synthetic mixture of metal ions.

Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification

Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g−1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g−1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g−1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility.

Hydrothermal Etching Assisted Crystallization: A Facile Route to Functional Yolk-Shell Titanate Microspheres with Ultrathin Nanosheets-Assembled Double Shells

We report a facile "hydrothermal etching assisted crystallization" route to synthesize Fe(3)O(4)@titanate yolk-shell microspheres with ultrathin nanosheets-assembled double-shell structure. The as-prepared microspheres possess a uniform size, tailored shell structure, good structural stability, versatile ion-exchange capability, high surface area, large magnetization, and exhibit a remarkable catalytic performance.

Surface‐Confined Synthesis of Silver Nanoparticle Composite Coating on Electrospun Polyimide Nanofibers

A methodology for fabricating hierarchical nanostructures by surface-confined synthesis of silver nanoparticles on electrospun polyimide nanofibers is reported. Through surface-confined imide cleavage at the dianhydride domain via immersion in an aqueous KOH solution, potassium polyamate coatings of accurately defined thickness are formed (at a rate of 25 nm h(-1) ). By utilizing the ion-exchange capability of the polyamate resin, silver ions are introduced through immersion in an aqueous AgNO3 solution. Subsequent reduction of the metal ion species leads to the formation of nanoparticles at the fiber surface. Two modes of reduction, chemical and thermal, are investigated in the report, each leading to distinct morphologies of the nanoparticle coatings. Via thermal reduction, a composite surface layer consisting of monodisperse silver nanoparticles (average diameter 5.2 nm) embedded in a re-imidized polyimide matrix is achieved. In the case of chemical reduction, the reduction process occurs preferentially at the surface of the fiber, leading to the formation of silver nanoparticles anchored at the surface, though not embedded, in a polyamic acid matrix. By regulating the modification depth, control of the particle density on the fiber surface is established. In both reduction approaches, the polyimide nanofiber core exhibits maintained integrity.

Analysis of Fiber Filter Media after 6 Years of Use as a First Flush Filter

Pollutants in rainwater often cause problems such as non-point source pollutant and deterioration of collected water quality in rainwater harvesting systems. Fiber filter media have been developed to resolve these problems by removing pollutants in rainwater by filtration and ion-exchange mechanisms. They have been also successfully applied for the treatment of first-flush rainwater. However, little information is available on the long-term efficiency and the lifetime of the fiber filter media. In this study, new and used fiber filter media were compared in terms of their filterability and ion-exchange capability. The used filter media samples were taken from a first flush filter in a rainwater harvesting system located in an elementary school in Kyonggi-Do. They were used from 2005 to 2010 without any replacement or cleaning. Water quality parameters of an inflow and outflow in the first flush filter were analyzed to quantify the on-site treatment efficiency of the used media. It was shown that the turbidity was removed by approximately 60% and COD was partly removed. The removal efficiency of particles by the used media was similar to that by the new media. Nevertheless, the removal efficiencies of nitrogen and phosphorous by the used media were substantially reduced when compared with the new media. This suggests that the fiber filter media should be periodically replaced to maintain high removals of nutrients. On the other hand, they can be used for more than 6 years if their primary purpose is to removal particles.

Ultrastructure and osmoregulatory function of the kidney in larvae of the Persian sturgeon Acipenser persicus

The localization of Na(+) , K(+) -ATPase (NKA) and the ultrastructural features of kidney were examined in larvae of the Persian sturgeon Acipenser persicus (L 31-41 mm total length and 182·3-417·3 mg). Investigations were conducted through light and electron microscopy and through immunofluorescence for NKA detection. The kidney nephrons consisted of a large glomerulus and tubules (neck, proximal, distal and collecting), which connected to the ureters. Posteriorly, ureters extended and joined together into a thin-walled ureter terminal sac. Ultrastructurally, the glomerular cells (podocytes) possessed distinctive pedicels that extended to the basal membrane. The proximal tubule (PT) showed two different cells. The cells lining the anterior part of PT possessed apical tall microvilli (c. 2·7 µm), a sub-apical tubular system, a basal nucleus and dense granules. Posteriorly in the cells, the sub-apical tubular system and granules were absent and round mitochondria associated with basolateral infoldings were found; the apical microvilli were reduced. Distal and collecting tubular cells showed the typical features of osmoregulatory cells, i.e. well-developed basolateral infoldings associated with numerous mitochondria. No immunofluorescence of NKA was detected in the glomeruli. A weak immunostaining was observed at the basolateral side of the cells lining the neck and PT. A strong immunostaining of NKA was observed in the entire cells of the distal tubules, collecting tubules and in some isolated cells of the ureters. In all immunostained cells, the basolateral region showed a much higher fluorescence and nuclei were immunonegative. In conclusion, the epithelial cells of kidney tubules had morphological and enzymatic features of ionocytes, particularly in the distal and collecting tubules. Thus, the kidney of A. persicus larvae possesses active ion exchange capabilities and, beside its implication in excretion, participates in osmoregulation.

Synthesis, characterization and analytical application of nano-composite cation-exchange material, poly-o-toluidine Ce(IV) phosphate: Its application in making Cd(II) ion selective membrane electrode

An organic-inorganic composite, poly-o-toluidine Ce(IV) phosphate was chemically synthesized by mixing ortho-toluidine into the gel of Ce(IV) phosphate in different mixing volume ratios. Effect of eluant concentration, elution behavior and pH-titration studies were carried out to understand the ion-exchange capabilities. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, UV–VIS spectrophotometry, FTIR, SEM/EDX, TGA–DTA, TEM (Transmission electron microscopy), XRD and SEM studies. The distribution studies revealed that the cation-exchange material is highly selective for Cd(II). Due to selective nature of the cation-exchanger, ion selective membrane electrode was fabricated for the determination of Cd(ІІ) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations.