Ion-exchange Fibers Research Articles

Fabrication and evaluation of cationic exchange nanofibers for controlled drug delivery systems

The number of ion exchange fibers in development has increased over the last several years. However, few studies have reported the use ion-exchange fibers in drug delivery system. In this study polystyrene nanofiber ion exchangers (PSNIE) were fabricated by electrospinning techniques, crosslinking and sulfonation. The degree of crosslinking and the ion exchange capacity (IEC) were determined. The morphology and diameter of the nanofiber mats were analyzed using scanning electron microscopy (SEM). Five cationic model drugs (dextromethorphan, chlorpheniramine, diphenhydramine, propranolol and salbutamol) were loaded into PSNIE. The loading capacity, release and release kinetics of the exchangers were investigated. PSNIE were successfully prepared by electrospinning and were allowed to crosslink for 10 min, resulting in a maximum IEC of 2.86±0.1 meq/g dry PSNIE. The diameter of the fibers after sulfonation was 464±35 nm. Dextromethorphan provided the highest loading in PSNIE while diphenhydramine gave the highest percentage release in both simulated gastric and intestinal fluid (SGF and SIF). The release kinetics of all drugs in SGF and SIF provided the best fit with the particle diffusion model. Our results showed that the development of a PSNIE-based drug delivery system was successful, and PSNIE were able to control drug release.

Thermally crosslinkable poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA)/polyvinyl alcohol (PVA) ion-exchange fibers

The aim of this study was to prepare poly(styrene sulfonic acid-co-maleic acid) (PSSA-MA)/polyvinyl alcohol (PVA) ion-exchange fibers using the electrospinning technique and a post-thermal treatment. First, intermediate PSSA-MA/PVA fibers were prepared from solutions of PSSA-MA/PVA combined at ratios of 0.2/1 to 1/1; the fibers were subsequently crosslinked at 80–150 °C for 0.25–7 h. The effect of the crosslinking time, the temperature and the PSSA-MA/PVA ratio on various properties of the obtained ion-exchange fibers was investigated. When the PSSA-MA/PVA ratios were greater than 0.4/1, bead formation was observed. Thus, only smooth fibers without beads prepared from PSSA-MA/PVA mixed in ratios up to 0.4/1 were subjected to the thermal crosslinking treatment. When the crosslinking time and temperature were increased, the degree of crosslinking increased, which caused a decrease in the water solubilization and water uptake and an increase in the Young’s modulus. These parameters also appeared to significantly affect the ion-exchange capacity value. The temperature and time for successful crosslinking were 120–140 °C and 1–7 h, respectively.

Removal of Cationic Dyes by Polyphenylene Sulfide-Based Strong Acid Ion Exchange Fiber

PPS-based strong acid ion exchange fiber was used to absorb cationic dye basic fuchsin and methyl blue in solution. The experimental results showed that the amount of methylene blue and basic fuchsin absorbed increased respectively with increasing of initial concentration from 100 to 600 mg/L. The adsorption capacity of the fiber was up to 604.81mg/g of basic fuchsin and to 618.94mg/g of methylene blue. The removal rate of the methylene blue reached 99.9% from 100 to 500mg/L, but of basic fuchsin from 100 to 300mg/L. Adsorption kinetic equation for basic fuchsin can be expressed as a pseudo-second-order dynamic process. The fiber is to be perfect prospect for the wastewater treatment because of its high adsorptive capacity and diffusion rate.

To enhance the efficiency of nefopam transdermal iontophoresis by using a novel method based on ion-exchange fiber

Background: In the system of the iontophoresis, the external electric field made the ions in the system moving directly, then, the current was generated. Because the current was contributed by all ions in the system, and the small ions with large amount often had higher conductibility than the drug ions, the fraction of the total current contributed by the drug ions was often low. It was the main reason for the generally low efficiency of the transdermal iontophoretic drug delivery.Objectives: The objective of this study was to find a novel method to increase the fraction of the total current contributed by the drug ions so as to enhance the drug's iontophoretic delivery.Method: Iontophoretic transport of nefopam hydrochloride solution and iontophoretic transport of nefopam assisted by ion-exchange materials, including ion-exchange resin, ion-exchange membrane and ion-exchange fiber, across the rat skin were investigated.Results: Both in vitro and in vivo iontophoretic transport experiments showed that the efficiency of the nefopam-fiber iontophoretic system for nefopam permeating across rat skin was the highest among four iontophoretic systems (nefopam solution, nefopam-resin, nefopam-membrane and nefopam-fiber).Conclusion: The results of this study suggested that there was an enhancement of nefopam across rat skin by ion-exchange fibers in ion-exchange fibers assisted iontophoresis. The present study has demonstrated the potential of a new approach of using ion-exchange fibers to improve the efficiency of the transdermal iontophoresis for cationizable drugs.

Ion-exchange and iontophoresis-controlled delivery of apomorphine

The objective of this study was to test a drug delivery system that combines iontophoresis and cation-exchange fibers as drug matrices for the controlled transdermal delivery of antiparkinsonian drug apomorphine. Positively charged apomorphine was bound to the ion-exchange groups of the cation-exchange fibers until it was released by mobile counter-ions in the external solution. The release of the drug was controlled by modifying either the fiber type or the ionic composition of the external solution. Due to high affinity of apomorphine toward the ion-exchanger, a clear reduction in the in vitro transdermal fluxes from the fibers was observed compared to the respective fluxes from apomorphine solutions. Changes in the ionic composition of the donor formulations affected both the release and iontophoretic flux of the drug. Upon the application of higher co-ion concentrations or co-ions of higher valence in the donor formulation, the release from the fibers was enhanced, but the iontophoretic steady-state flux was decreased. Overall, the present study has demonstrated a promising approach using ion-exchange fibers for controlling the release and iontophoretic transdermal delivery of apomorphine.

Extraction of zinc from aqueous solutions by electrically polarized cation exchange fibers

The process of treating galvanizing bath rinsing water by electrodialysis method with dialysate chamber filled with Fiban-K cation exchange fiber was investigated. The relationship between electromigration of zinc ions and electric current density was shown to have a maximum value within a range of 8–12 mA/cm2. Within this range the electromigration flow of zinc ions in the presence of ion exchange fiber increases by ∼20%, transport of hydrogen ions reaches 11.3% of the total flow of cations, residual concentration of zinc ions in dialysate in quasi-stationary mode at a current density of >10 mA/cm2 does not exceed 2–4 mg/dm3, and without chamber loaded—10–15 mg/dm3.

Extraction of pigment from sugarcane juice alcohol wastewater and evaluation of its antioxidant and free radical scavenging activities

Pigment was extracted to decolor the sugarcane juice alcohol wastewater and its antioxidant activities were evaluated. The pigment was extracted using ion exchange fiber along with macroporous resin D-101 as the absorbent and an ethanol-water mixture (6:4, v/v) as the eluent. Total flavonoid and phenolic contents of the pigment were determined. DPPH radical scavenging ability and reducing power of 1.0 mg/mL of the pigment were approximately 78.5 and 16.8%, respectively, compared to 1.0 mg/mL of the tea polyphenol (positive control). The hydroxyl radical scavenging ability of 10.0 mg/mL of the pigment was about 92.5% compared to that of positive control. The DPPH radical scavenging ability of the pigment was enhanced significantly with thermal treatment at 70 and 100°C. The result shows the proposed procedure can be effective to decolor such wastewater and to get antioxidative pigment.

Carbon Dioxide Regeneration of Ion Exchange Resins and Fibers: A Review

Alternative chemicals for the regenerant of ion exchangers have been the subject of research for the past sixty years. The advances spanning this time period have been significant and demonstrated at the laboratory, pilot, and commercial scale. The use of carbon dioxide as a regenerant has several significant benefits including cost savings, waste minimization, and carbon dioxide sequestration, with applications including: chemical synthesis, desalination, demineralization, metals removal and hardness removal. Having originally been pursued as a means of reducing costs of regenerant chemicals, regeneration with carbon dioxide has also been described as a non-polluting separation process and has shown significant environmental benefits. Its use as a regenerant circumvents the use of brines, strong acids, or other aggressive chemicals and with the advent of new materials such as ion exchange fibers, the list of potential applications will continue to grow. This review discusses some of the significant advances during the history of this environmentally benign regeneration process.

Comparison of Different Ion-Exchangers’ Performances for Removal of Cadmium(ll) from Aqueous Solution

In this paper, comparison of the ion-exchange characteristics of removal cadmium (Ⅱ) ions from aqueous solution was investigated. In the experiments, three strong cation-exchangers, 732 resin, K-1 fiber and ZB-1 fiber with sulfonate groups, weak cationic exchanger 724 resin with carboxylate groups and X-1 chelating fiber with diethylamino functional groups as well as the AK-22 amphoteric fiber with amino and carboxylate groups were used. In the pH value range from 2.0 to 7.0, all the candidate materials had the maximal removal Cd (Ⅱ) up to 98% except AK-22 (only 65%). The loading and eluting kinetics results showed that the exchange rate of ion-exchange fibers (especially ZB-1) were higher than ion-exchange resins. Therefore, it was found that ZB-1 ion-exchange fiber was the most effective for removal and elution of Cd (Ⅱ) and had the potential application for the purification of waters polluted by Cd (Ⅱ).

Ibuprofen ion-exchange fiber complex: improved dissolution and gastric tolerance based on ion exchange

The purpose of the present study is to develop a novel method to improve the dissolution of water-insoluble drug ibuprofen and the gastric tolerance of this non-steroidal anti-inflammatory drug which has potentially serious gastrointestinal side effects. This method is based on ion exchange of ion-exchange fibers. Water-insoluble drug ibuprofen was dispersed in deionized water, and then the ion-exchange fibers in OH– type was immersed in it. Ibuprofen and the active groups of the ion-exchange fibers combined into ion pairs based on the acid–base reaction. This drug carrier did not release drugs in deionized water, but in water solution containing other ions it would release the drugs into the solution by ion exchange. Confirmed by the X-ray diffraction and the scanning electron microscopy, the ibuprofen combined onto the ion-exchange fibers was in a highly molecular level dispersed state. The improved dissolution of ibuprofen ion-exchange fiber complexes is likely to originate from this ibuprofen’s highly dispersed state. Due to this, ibuprofen’s highly dispersed state, ibuprofen ion-exchange fiber complexes significantly decreases the gastrointestinal side effects of ibuprofen by avoiding the solid ibuprofen’s educing. The present study showed that ibuprofen ion-exchange fiber complexes have the two-fold advantages. One is to improve the dissolution of ibuprofen. The other is to decrease the ibuprofen’s gastrointestinal toxicity.

Ketoconazole ion-exchange fiber complex: a novel method to reduce the individual difference of bioavailability in oral administration caused by gastric anacidity

Water insoluble faintly alkaline drugs often have potential absorption problem in gastrointestinal tract in oral administration for patients with gastric anacidity. The purpose of the present study is to develop a novel method to improve the absorption of the water insoluble faintly alkaline drug in peroral administration. This method is based on ion exchange of ion-exchange fibers. Water-insoluble faintly alkaline drug ketoconazole was used as a model drug. Ketoconazole and the active groups of the ion-exchange fibers combined into ion pairs based on the acid-base reaction. This drug carrier did not release drugs in deionized water, but in water solution containing other ions it would release the drugs into the solution by ion exchange. Confirmed by the X-ray diffraction and the differential scanning calorimetry (DSC), the ketoconazole combined onto the ion-exchange fibers was in a highly molecular level dispersed state. The improved dissolution of ketoconazole ion-exchange fiber complexes is likely to originate from this ketoconazole’s highly dispersed state. Furthermore, due to this ketoconazole’s highly dispersed state, ketoconazole ion-exchange fiber complexes significantly decreased the individual difference of absorption in oral administration of ketoconazole caused by the fluctuation of the acid degree in the gastric fluid.

Electroremediation of contaminated soil by heavy metals using ion exchange fibers

Electrokinetic remediation has become a usual process for the removal of contaminants from soils. Various materials and products are used in the electrokinetic treatment to improve the efficiency of this technique. Ion exchange membranes have been tested resulting in an enhancement of the metal removal selectivity and permits good control of the pH. On the other hand, the use of membranes permits the contaminants to be isolated and concentrated in a separate compartment. In this work, other materials different than membranes have been tested through electroremediation of a kaolinite specimen contaminated with lead and zinc. Ion exchange fibers have been tested playing similar role of membranes. However, fibers are based on a cellulosic structure which gives to the fibers hydrophilic properties. Thus, fibers have shown a good mechanical structure and have enhanced the electro-osmotic flux with a better selectivity against ions less hydrated as lead. Removal yields were increased for lead and zinc while the latter is more retained inside the cation exchange fibers.

A novel method to enhance the efficiency of drug transdermal iontophoresis delivery by using complexes of drug and ion-exchange fibers

The main reason for generally low efficiency of the transdermal iontophoretic drug delivery is that the fraction of the total current contributed by the drug ions is very small. The objective of this study was to find a method to increase the fraction of the total current contributed by the drug ions so as to enhance the drug's iontophoretic delivery. Iontophoretic transport of diclofenac solution and diclofenac assisted by ion exchange materials, including ion-exchange resin, ion-exchange membrane and ion-exchange fiber, across the rat skin were investigated. Both in vitro and in vivo iontophoretic transport experiments showed the amount of diclofenac permeated across rat skin from the diclofenac-fibers was highest among those from the diclofenac simple solutions and ion exchange materials complexes. The results of this study suggested that there is an enhancement of drug across rat skin by ion-exchange fibers in ion-exchange fibers assisted iontophoresis. The present study has demonstrated the potential of a new approach using ion-exchange fibers to enhance transdermal iontophoretic transport of an ionizable drug.

Removal of Copper-Cyanide Complexes from Electroplating Industry Effluents by Ion-Exchange Fiber

Removal of copper-cyanide complexes from electroplating industry effluent were studied by using an ion-exchange process. A kind of polypropylene strong alkaline anion exchange fiber was used to perform packed beds continuous experiments. The conditions of adsorption were wastewater pH value 9.0 and flow rate 90-120 BV•h-1 at room temperature. The packed beds were exhausted at 1300 bed volumes for copper-cyanide complexes The elution of copper-cyanide complexes from ion-exchange fiber was studied. The results showed that copper-cyanide complexes were easily eluted from ion exchange fiber using either 2.0 mol•L-1 NaNO3 or NaCl. With 1.0 mol•L-1 NaNO3 solution at 30 BV•h-1, the regenerating rate of copper-cyanide complexes was more than 95%.

Studies on Dynamic Adsorption and Desorption of Total Flavonoids with Ion-Exchange Fiber

The adsorption and desorption property of total flavonoids with ion-exchange fiber were studied. The kinetic study on dynamic adsorption and desorption indicates that the adsorption and desorption property of fiber is function of the concentration、pH value and flow velocity of column liquid. Flavonoids can be effectively desorbed by ethanol.

Analysis of Iron in Copper, Copper Oxide and Copper Nitrate by Solid-Phase Extraction ICP-AES Method

The reasearch shows that when the mass ratio of copper to iron is equal or greater than 100, the influence of copper on the determination of trace iron can not be ignored. To eliminate the interference, the polypropylene radical strong base anion ion exchange fiber was taken as the solid phase extraction solvent. Extraction and separation of trace iron (Ⅲ) from solution copper (Ⅱ) by the extraction solvent was studied. The extraction conditions including of adsorption and elution were optimized. The strong base anion ion exchange fiber was put into the analysis solution with the medium of 6mol/L HCl. After adsorption 1h by vibration on the oscillator, adsorptive iron(Ⅲ) was eluted with the 1mol/L HCl. The concentration of iron (Ⅲ) in the eluate solution was mesured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that the residual Cu (Ⅱ) in the eluate solution did not affected the accurate determination of iron. The iron in metal copper, copper oxide and copper nitrate were separated and determinated, and the RSDs(n=3) were between 2.3% and 4.2%, the recoveries were between 96% and 103%, the detection limit of the method was 0.011μg/mL.

Preparation of cellulosic ion exchange fiber using an ionic liquid as reaction reagent and medium

AbstractA cellulosic ion exchange fiber (CIEF) was prepared by using room‐temperature ionic liquid 1‐(3‐chloro‐2‐hydroxypropyl)‐3‐methylimidazolium chloride as reaction reagent and medium. The results showed the degree of substitution of the CIEF was up to 0.78. The product was characterized by Fourier transform infrared spectrometry, thermogravimetric analysis, scanning electronic microscope. The thermal stability of the CIEF was over 200°C. The adsorption experiments of CIEF for Cr(VI) were performed. The adsorption capacity of CIEF for Cr(VI) was found to be 196.1 mg g−1 at 30°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

Submicron Ion-Exchange Fibers of Polystyrene and Styrene-Butadiene-Styrene Copolymer Blends

In the present study, submicron ion-exchange fibers (IEFs) of polystyrene (PS) and its blends with styrene-butadiene-styrene block copolymer (SBS) were prepared by electrospinning and postsulfonating modification. Scanning electron microscopy (SEM) images showed that the diameters of the fibers enlarged significantly after treatment and the surfaces become rougher. Mechanical properties analysis showed that the electrospun fibers (EF) and the IEFs from PS/SBS blend fabrics possessed better mechanical performances than those from pure PS. The ion-exchange capacity (IEC) of 4.35 mmol/g and and copper ions (Cu2+) adsorption value of 3.08 mmol/g for IEFs from PS/SBS blends were both higher than that of IEFs from pure PS and the conventional IEFs produced by coating or grafting fibrous substrates with functionalized resins or monomers. Dynamic adsorption experiments were made to test the behavior of adsorption for Cu2+. The results of dynamic adsorption experiments with Cu2+ showed that the IEFs from PS/SBS would quickly purify 3000 ml waste water containing Cu2+ (100 mg/L), and the removal rate for Cu2+ reached 96.5% even at the flow rate of 12 ml/min. The study provided an absorbent with a high dynamic adsorption capacity for removing Cu2+ from waste water.

The state of water in different forms of sulfo ion-exchange fiber

The state of water in the copper, zinc, and cobalt forms of VION KS-3 ion-exchange fiber is investigated by derivatography. The presence of differently bound water is found. For each step of water removal, hydration numbers of the fiber are determined. It is shown that the amount of water in the fiber depends on its ionic form.

Synthesis and characterization of sodium bis(2-ethylhexyl) sulfosuccinate based tin(IV) phosphate cation exchanger: Selective for Cd 2+, Zn 2+ and Hg 2+ ions

The surfactant sodium bis(2-ethylhexyl) sulfosuccinate based tin(IV) phosphate (AOT-SnP) fibrous ion exchanger has been synthesized and characterized by using different physico-chemical methods. The characterization of the exchanger was performed by using infrared (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and elemental analysis. The ion exchange property was studied by determining the ion exchange capacity, elution and concentration behavior of the cation exchanger. The thermal behavior of exchanger was studied by performing ion exchange capacity at different temperatures. Adsorption studies on the synthesized material showed that it is highly selective for Cd 2+, Zn 2+and Hg 2+ ions. Therefore, the separation of Cd 2+, Zn 2+and Hg 2+ ions from the synthetic waste water has been performed on its column and observed to be quite effective in presence of acid, alkali, alkaline earth and other transition metals.