Ion-exchange Fibers Research Articles

Removal of copper ions from dilute synthetic solution using staple ion exchange fibres: Equilibrium and kinetic studies

The removal of heavy metals like copper (Cu2+ ions) from industrial waste streams is necessary so as to prevent detrimental effects to the environment and human health. One of the effective adsorbents that can be used for the removal of heavy metals are ion exchange fibres (IEFs). Therefore, this paper focuses on equilibrium and kinetic studies of the Cu2+ ions removal process using IEFs. In addition, selectivity and elution tests were also conducted. The equilibrium and kinetic behaviour of Cu2+ ions removal was best described by the Temkin and the pseudo-second-order model, respectively. The results also indicated that the IEFs had a higher selectivity for Cu2+ ions than the other ions (cobalt (Co2+), nickel (Ni2+), zinc (Zn2+), manganese (Mn2+) and magnesium (Mg2+)) studied at pH 3 and 62mg of Cu2+ ions per gram of IEFs were loaded at this pH. It was also found that the percentage of metal eluted from IEFs increased with an increase in eluent concentration. Furthermore, the ion exchange rate was found to be dependent on the number of ionizable functional groups as suggested by the pseudo-second-order model.

Synthesis, characteristics and adsorption properties of polyphenylene sulfide based strong acid ion exchange fiber

A novel strong acid ion exchange fiber (HO3S-BC-XDC-PPS) was prepared via crosslinking and grafting copolymerization of 1,4-bischloromenthyl benzene (XDC), benzyl chloride (BC) on polyphenylene sulfide (PPS) matrix, as well as following sulfonation reaction. The physicochemical structures and properties of the fibrous ion exchanger were characterized with Fourier transform infrared, scanning electron microscopy, thermogravimetric analysis, elementary analysis and chemical titration, respectively. Compared with the preparation of traditional polypropylene–styrene–divinylbenzene-based ion exchange fibers, the synthesis strategy of PPS-based strong acid ion exchange fiber avoided the complicated irradiation grafting process with 60Co or other radiation facilities. Owing to the existing of thioether (Ar―S―Ar) and sulfoxide (―SO―) unit in fibrous matrix, a super-equivalent adsorption phenomenon for Cu(II) ion was observed. The HO3S-BC-XDC-PPS fiber possessed high exchange capacity (≥3.0 mmol/g) and excellent thermostabilities, and the exchange capacity and desorption rate were not decreased after six adsorption desorption cycles. Copyright © 2014 John Wiley & Sons, Ltd.

Controlled transdermal delivery of leuprorelin by pulsed iontophoresis and ion-exchange fiber

Poor transport efficacy and issues related to biological variation are major concerns in the development of novel iontophoretic devices for the transdermal delivery of therapeutic peptides. The objective of this study was to examine the impact of constant and pulsed current on the transport of nonapeptide leuprorelin acetate across porcine epidermis. Also, the potential of drug delivery system combining iontophoresis and ion-exchange fibers as drug matrices for the delivery of the same peptide was tested. The present study demonstrated the benefit of pulsed current (Tn=2.59×10−4) over constant current (Tn=1.7×10−4) in terms of more efficient transdermal peptide transport. An increase in the delivery of electroosmotic marker by pulsed current was due to the combined effect of more pronounced electroosmotic transport and reduced inhibition of passive transport. We also showed a promising approach using ion-exchange fibers for controlling the release and iontophoretic transdermal delivery of peptides. Positively charged leuprorelin acetate was bound to the ion-exchange groups of cation-exchange fibers until it was gradually released by mobile counter ions in the external solution. Transdermal flux from acrylic acid grafted Smopex®-102 fibers remained higher (Jss=0.71μg/hcm2) than from sulfonic acid grafted Smopex®-101 fibers (Jss=0.31μg/hcm2) due to better drug release.

Polyamine Type IEF’s Adsorption Efficiency to Cyanide and Copper

The adsorption capacity of two kinds of Ion exchange fiber (IEF) was compared to treat the wastewater contained CNT and Cu, then adsorption efficiency of Poly Acrylo-amidino Triethylene tetramine Fiber (PATAF) was studied under different pH (7.5-9.0) and flow rate (80.4-160.8 BV⋅h-1). The concentration of cyanide and complex ion were measured at pH=8, flow rate=126.0 BV⋅h-1, and the desorption conditions were studied under different concentration and flow rate.

Physico-chemical effects of ion-exchange fibers on electrokinetic transportation of metal ions

Ion-exchange textiles can be used in electroremediation of heavy metal contaminated liquid effluents. In this work, the behavior of FIBAN ion-exchange textiles was tested for the transportation of two heavy metals: lead and zinc, under the effect of a constant direct electric current. Detailed characterization of fibers has been carried out in order to determine the effect of their structure on the retention of heavy metal during their electrokinetic transport. Ion-exchange fibers structure was studied by electronic scan microscopy, X-ray fluorescence, spectrogammametric analysis and Fourier Transformed Infrared Spectroscopy/Attenuated Total Reflectance. Hittorf method was used to determine the transport number of Pb2+ and Zn2+ during the electrokinetic treatment.

Synthesis, characterization and analytical applications of N-dodecyl pyridinium chloride-cerium (IV) phosphate fibrous ion exchanger: selective for Hg(II) and its binary separations

An intercalated hybrid fibrous ion exchanger has been synthesized by incorporating N-dodecyl pyridinium chloride with the inorganic cation exchanger, cerium (IV) phosphate. The synthesized, N-dodecyl pyridinium chloride-cerium (IV) phosphate (DPC-CeP) cation exchanger was characterized using X-ray diffraction studies, SEM, thermogravimeric (and differential thermogravimetric) analysis and elemental analysis. The ion-exchange characteristics (ion-exchange capacity, elution and concentration behaviour) and thermal stability were also determined by usual chemical method. The adsorption studies for alkaline earths and heavy metal ions on the synthesized material were also performed in different acidic media. DPC-CeP has been found to be selective for Hg(II) ions. Hence, some binary separations of Hg(II) ions from the mixture containing other metal ions have been carried out on its column, exploring the potential role of the synthesized material in environmental studies and water treatment.

The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences.

Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug–fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug–fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid.

Oral sustained-release suspension based on a novel taste-masked and mucoadhesive carrier–ion-exchange fiber

The purpose of this study was to evaluate the feasibility of ion-exchange fiber ZB-1 as a novel carrier in oral taste-masked mucoadhesive sustained-release suspensions. Propranolol (PPN) hydrochloride was selected as a model drug with good water solubility, short half life and bitter taste. The PPN-fiber complexes (PF) were prepared by a batch process and coated with Eudragit® RS100. Gamma scintigraphy was performed on fasted volunteers revealed about 30% ZB-1 and more than 50% coated ZB-1 were still remaining in the stomach at 6h. In vitro results showed the releases of PF and coated PPN-fiber complexes (C-PF) were sustained. The release, drug content and particle size of C-PF were influenced by coat to core ratio, concentration of coating material and rotation rate. The suspension was stable after standing for 30 days in 0.5% Carbopol® with no release rate and taste changed. The administration of C-PF suspension to rats resulted a significant different (P<0.05) improvement of the plasma drug level and prolongation of the release. However, because of the burst effect, the Cmax values of PF suspension didn't differ from drug solution (P>0.05). Furthermore, a linear relationship between in vitro dissolution and in vivo absorption was observed.

Hydrolyzed Poly(acrylonitrile) Electrospun Ion-Exchange Fibers.

A potential ion-exchange material was developed from poly(acrylonitrile) fibers that were prepared by electrospinning followed by alkaline hydrolysis (to convert the nitrile group to the carboxylate functional group). Characterization studies performed on this material using X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier-Transform infra-red spectroscopy, and ion chromatography confirmed the presence of ion-exchange functional group (carboxylate). Optimum hydrolysis conditions resulted in an ion-exchange capacity of 2.39 meq/g. Ion-exchange fibers were used in a packed-bed column to selectively remove heavy-metal cation from the background of a benign, competing cation at a much higher concentration. The material can be efficiently regenerated and used for multiple cycles of exhaustion and regeneration.

Dual drug load and release behavior on ion-exchange fiber: influencing factors and prediction method for precise control of the loading amount

Ion-exchange fiber undergoes a stoichiometric exchange reaction and has large exchange capability, which makes it a promising candidate as a multiple drug carrier. Because combinatorial effects can act synergistically, additively or antagonistically depending on the ratio of the agents being combined, the objective of this study was to learn the dual drug loading of ion-exchange fiber and develop a mathematical method for precisely control of the loading amount. Atenolol and Gatifloxacin, with different loading behaviors into strong cationic ion-exchange fiber ZB-1, were used to build a representative of dual loading. Not suitable pH value of drug solutions could make simultaneous loading fail, while the change of drug solution volume hardly affected the equilibrium. Ion-exchange groups occupied by the drug which owned lower affinity to fiber could be grabbed by the higher affinity drug, indicating the existence of competition between drugs. Thermodynamic model was introduced to guide the loading prediction and a favorable relevance had been shown between determined and predicted data. The release behaviors of each drug from dual drug–fiber complex were similar to those from single drug–fiber complexes.

Loading and Release of Amine Drugs by Ion-Exchange Fibers: Role of Amine Type

With more production and application of ion-exchange fibers (IEFs), it becomes necessary to understand the interaction between IEFs and amine compounds, an important group of organic drugs and structural components of large organic molecules in biological systems. However, so far few experimental studies have been conducted to systematically investigate the exchanging mechanism of amine compounds to IEFs. Therefore, 15 amine drugs were selected to investigate the effect of amine type on the loading and release of them from the related IEFs. Loading affinity of these drugs by IEFs decreased in the order of secondary, tertiary, and primary. The following items: basicity, aromaticity, molar volume, rotatability, and so on, were emphatically discussed to address the underlying mechanism of drug loading and releasing extent and rate of IEFs. It was evident that strong alkaline drugs strengthened the ionic bond between the amine groups and IEFs, and thus the loading affinity. These results will advance the understanding of the exchanging behavior of IEFs in the drug delivery system.

The Drug Loading Kinetics Mechanism of Ion Exchange Fiber as a Novel Kind of Drug Carrier Material

The adsorption of Fenazoxine hydrochloride was investigated by performing batch kinetic sorption experiments. Experiments were carried out as function of contact time, initial concentration. Adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetics equations. It showed that the pseudo-second order kinetic equation can describe the adsorption kinetics best. The results indicate that ion-exchange fiber is suitable as drug carriers for loading drugs.

Investigation of mechanisms of interaction between inulinase from Kluyveromyces marxianus and the matrices of ion-exchange resins and fiber

It is established that ion exchange resins AV-17-2P, KU-2, AV-16-GS, AM 21A, IMAC-HP, PUROLITE and fiber VION KN-1 can be applied as carriers for inulinase immobilization. The analysis of IR spectra for an enzyme, carriers and heterogeneous enzyme preparations showed that inulinase binding to matrices of various carriers occurs in general through electrostatic interactions. It is assumed that the mechanisms of interaction between inulinase from Kluyveromyces marxianus and the matrices of cation- and anion exchange polymers differ essentially from each other: different sites of protein molecule take part in adsorption that causes various conformational reorganizations in an enzyme molecule.

Thermodynamics of Cr(VI) Adsorption on Thiourea Chelating Ion Exchange Fiber

A chelating ion exchange fiber containing thioureido groups for the removal of Cr (VI) has been prepared from chloramethylated styrene grafted polypropylene fiber (2.96 mmol/g Cl) reacted with thiourea, batch adsorption experiments are adopted to investigate its adsorption equilibrium properties, Adsorption isotherms at various temperatures were obtained. Langmuir linear equation model can well describe the adsorption equilibrium data suggesting that the adsorption process involves both chemisorption and physisorption. The values of thermodynamic parameters, including ΔH, ΔG and ΔS, indicate that the adsorption of Cr (VI) is a spontaneous, entropy-driven and endothermic process.

Tramadol loading, release and iontophoretic characteristics of ion-exchange fiber

The objective of this study was to investigate the drug loading, release and iontophoretic characteristics of strong acidic ion-exchange fiber, using tramadol hydrochloride as a model drug. The complex of charged model drug and ion-exchange fiber was studied as a new approach to achieve controlled drug delivery. Structural characterization of the fiber was elucidated through different approaches including differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and infrared spectroscopy (IR). And the mechanism of drug binding into ion-exchange fibers was validated to be ion-exchange. The drug loading into and release from ion-exchange fiber were affected by the concentration, volume and valence of the counter-ions in the external solution. Iontophoresis could significantly increase the delivery rate and amount of transdermal drug, and the iontophoretic dose could be easily controlled by adjusting the current intensity and the amount of release medium. The tramadol could be steadily released both from the drug-loaded fiber and drug solution when applied the iontophoretic method, which was in disagreement with the previous publications. As a drug reservoir, ion-exchange fiber has good regularity of drug loading, release and iontophoretic characteristics.

The Drug Loading Thermodynamics Mechanism of Eight Cationic Drugs’ Adsorption onto Ion Exchange Fiber

The adsorption of eight drugs (Log P range from-2.64~8.98) was investigated by performing batch adsorption experiments. Experiments were carried out as function of contact time, initial concentration and temperature (25-60°C). The equilibrium adsorption data of drugs on ion-exchange fiber were analyzed by Langmuir and Freundlich models. The results indicate that the Langmuir model provides the best correlation of the experimental data. The results indicate that ion-exchange fiber is suitable as drug carriers for loading drugs.

Mathematical Simulation and Experimental Investigation of Propranolol Hydrochloride Loading/releasing from Ion Exchange Fibers

Ion-exchange fibers are promising drug delivery carriers,so it is important to predict the loading efficiency and loading capacity in the loading process and accurate prediction and control of the drug release profile(s) from the fibers for a given fiber-drug system under precise loading conditions. Impact of initial drug concentration, drug solution volume and fiber dose on the drug loading process and effect of loading drug concentration drug solution volume, fiber dose on the drug releasing process were assessed experimentally and theoretically. Two mathematical models based on Donnan theory and ion exchange equilibrium theory taking into account the chemical partition coefficient of D+, Na+and Cl-were developed to simulate the drug loading onto ion exchange fiber and releasing process respectively with the aim to gain mechanistic understanding on the factors affecting these two processes. Good correspondence between the experiment and theory has been established.

Selection of Scheme for Impregnation of Sodium Titanate onto Ion-Exchange Fibers for Radioactive Strontium Removal from Seawater

Selection of Scheme for Impregnation of Sodium Titanate onto Ion-Exchange Fibers for Radioactive Strontium Removal from Seawater

Synthesis and properties of new N,S-containing fibrous ion exchangers

New N,S-containing fibrous ion exchangers were prepared by polymer-analogous transformations of Nitron fiber, involving amination with polyethylenepolyamines (ethylenediamine and diethylenetriamine), followed by the reaction of the aminated fiber with carbon disulfide. The materials obtained efficiently take up silver ions from multicomponent aqueous solutions of metal ions and from dilute solutions containing calcium ions.

The determination of trace amount of Cr(VI) and As(V) in aqueous solution by UV–vis spectrophotometer assisted with preconcentration on a quaternary ammonium ion exchange fiber-in-tube

A simple and sensitive method was developed for the determination of Cr(VI) and As(V) using a microcolumn packed with quaternary ammonium ion exchange fiber for the preconcentration of trace amount of Cr(VI) and As(V) prior to their determination by UV–vis spectrophotometer. It was found that Cr(VI) and As(V) could be almost completely retained on ion-exchange fiber in the pH range of 5.0–6.5 and 3.5–5.0, respectively. With a mixture eluent of 5% (w/v) NH4Cl and 10% (v/v) NH3/H2O solution, they could be almost quantitatively eluted. Under the optimized conditions, the detection limits were 0.2 μg L−1 for Cr(VI) and 0.8 μg L−1 for As(V) with enrichment factors of 96.5 and 95.3, respectively. The relative standard deviations for nine replicate determinations at 5 and 10 μg L−1 for Cr(VI) and As(V) were 2.2 and 3.4%, respectively. These results proved that the proposed method had a potential in the analysis of trace metal ions with good accuracy in real samples.