Hybrid Cation Exchange Research Articles

Ion exchange and Thermal Studies on n-butyl acetate zirconium(IV) phosphate: A Novel Hybrid Cation exchanger

n-butyl acetate zirconium (IV) phosphate has been reported as a novel hybrid ion exchanger, namely an organic-based hybrid ion exchanger. This newly reported material has been characterized by a number of physico-chemical characterization techniques including FTIR analysis, SEM study, UV-Vis spectrophotometry and elemental analysis. In addition to describing its method of synthesis, this research also reports on the characterization of its ion exchange properties such as its ion exchange capacity, concentration study, elution study and recycling study. Thermal behavior of the reported exchanger has also been explored at various temperatures revealing 91.4% of retention in ion exchange capacity on heating upto 2000C and 74.5% upto 4000C which exhibits the way to explore its applications in higher temperature ranges.

Kinetics of heavy metal ions removal from aqueous solutions using synthesised composite hybrid cation exchanger

ABSTRACT Hybrid organic–inorganic materials make it possible to combine beneficial organic and inorganic properties into a single molecular-scale composite. In this study, the removal efficiency of synthesized organic–inorganic hybrid cation exchanger: nylon-6,6, Zr (IV) phosphate with respect to Cu2+, Zn2+ and Cd2+ has been investigated in order to take into account its potential use to clean up wastewaters from heavy metals. Metal concentrations in solution of 0.02 and 0.2 mol/L were used in the batch technique. For both lower and higher initial concentration, the process was fitting to both first and pseudo-first-order-kinetic model, while it is also consistent with the intra-particle diffusion model. Particle diffusion is the rate-limiting step in the multistep process that is primarily controlled by external mass transfer. Moderate activation energy values confirmed that the process is a combination of both physisorption and chemisorption. The order of removal may be presented as Cu2+ > Zn2+ > Cd2+.

Biological and environmental studies on pectin-zirconium (IV) phosphate, a biopolymer doped hybrid cation exchanger

Pectin, a biological macromolecule-doped zirconium (IV) Phosphate is reported as a novel ion exchanger which has been characterized by few physico-chemical characterization techniques such as FTIR analysis, XRD, TGA/DTA, DSC, SEM study, UV–vis spectrophotometry and elemental analysis. The method of synthesis along with ion exchange characterization has also been reported including ion exchange capacity, thermal stability, concentration and elution study. Adsorption study has been explored for few alkaline earths and transition metal ions in several acidic media. Based on adsorption study, it has been found that the reported ion exchanger has shown enantioselectivity for mercury (II) ions. Hence, few binary separations have been performed on lab-made samples depicting that the material would be of great importance in water pollution control. In addition to it, antimicrobial activity of the material on some microorganisms has been studied revealing the highest antimicrobial activity towards Ecoli ESS 2231 which would be added application in terms of water purification. Moreover, the exchanger is found stable up to 200 °C by retaining 90.6 % of its capacity whereas up to 400 °C, it exhibits decrement by retaining 75.5 % of its ion exchange capability which provides a way to explore applications of the exchanger at a higher range of temperatures.

Fabricating a Partially Fluorinated Hybrid Cation-Exchange Membrane for Long Durable Performance of Vanadium Redox Flow Batteries.

The long-term durability of vanadium redox flow batteries (VRFBs) depends on the stability and performance of the membrane separator. We have architected a hybrid membrane by uniform dispersion of MIL-101(Cr) (Cr-MOF) in a partially fluorinated polymer grafted with sulfonic acid groups (PHP@AMPSCr-MOF(1.0)). The single cell VRFB performance of the PHP@AMPSCr-MOF(1.0) membrane was studied in comparison with the Cr-MOF incorporated Nafion membrane (NafionCr-MOF(1.0)) and showed an excellent result with 97.5% Coulombic efficiency (CE) at 150 mA/cm2 without any significant deterioration in the charge-discharge process for 1500 cycles (over 650 h). Meanwhile, the CE value of the NafionCr-MOF membrane (94.5%) deteriorated after 800 cycles (about 360 h) under similar conditions. The high VRFB performance of the PHP@AMPSCr-MOF(1.0) membrane has been attributed to the synergized properties and good interactions between Cr-MOF and partially fluorinated polymer matrix responsible for the creation of hydrophilic proton-conducting channels to achieve high selectivity. Furthermore, the cost-effective polymer and thus membranes may open new windows for practical applications in other energy devices such as fuel cells, electrolysis, and water treatment.

Denitrification of nitrate in regeneration waste brine using hybrid cation exchanger supported nanoscale zero-valent iron with/without palladium nanoparticles

The Sustainable Development Goals require that reducing waste is a priority. This work described the application of an innovative zero-waste hybrid ion exchange nanotechnology that concurrently removed nitrate and induced denitrification to ammonia, with the ability to generate fertilizer for the agriculture sector from the recycled by-products. Herein, hybrid cation exchanger-supported zero-valent iron (Fe0), and bimetallic Fe0/Pd nanoparticles (HCIX-Fe0 and HCIX-Fe0/Pd) were synthesized and successfully validated for denitrification of nitrate in spent waste brine that contained nitrate. The kinetics of nitrate catalysis by both HCIX-Fe0 and HCIX-Fe0/Pd were compared and presented by six kinetic models, namely, zero-order, pseudo first- and second-order reaction, pseudo first- and second-order adsorption, and Elovich. HCIX-Fe0/Pd displayed a higher kinetic value than HCIX-Fe0, with k1 of 0.0019 and 0.0026 min−1, respectively. Nitrate was predominantly catalysed to NH4+ at a ratio of ammonia to other nitrogen compounds of around 80:20. Although HCIX-Fe0/Pd showed slightly better (14%) kinetic results, it was determined as unfavourable for real-life application due to low selectivity toward N2 gas and the need to use H2 gas. Based on practicability, the HCIX-Fe0 was further validated. The effect of salt (using NaCl) and the role of initial pH conditions were optimized and discussed. The recovery of nitrate removal was also calculated, and a recovery range of 91.42–99.14% was obtained for three consecutive runs. The sustainable, novel, zero waste hybrid ion exchange nanotechnology using the combination of two fixed-bed columns containing nitrate-selective resin for nitrate removal and novel HCIX-Fe0 for nitrate reduction to NH4+ may be a promising sustainable solution toward the goal of discharging zero nitrate waste to the environment.

Ion exchange behavior of novel Pani -Ti(IV) phosphosulphosalicylate hybrid cation exchange material for the selective separation of Pb(II) in environmental remediation

ABSTRACT A new hybrid cation exchange material PANI-Ti(IV) phosphosulphosalicylate was synthesized by intercalating polyaniline (PANI) into Ti(IV) phosphosulphosalicylate (Ti(IV) PSS) using sol-gel chemical route. Then, it is renewed into H+ form and used as an adsorbent for the removal of Pb(II) from aqueous solution. The morphology and structure properties of the as prepared hybrid cation exchange material were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET), thermo gravimetric analysis (TGA-DTG), and Transmission Electron Microscopy (TEM). The sorption experiment for Pb(II) removal was performed using batch method. Dependence of adsorption on contact time, exchanger dose, Pb(II) initial concentration, pH, and temperature has been studied to achieve the optimum conditions. The adsorption isotherm, kinetics, and thermodynamics of PTPSS for Pb(II) were studied. The results of the above mentioned analyses show that the adsorption isotherm process of Pb(II) on PTPSS was closely related to Langmuir model (r2 > 0.998). The adsorption kinetic process fits well with the pseudo-second order equation. Thermodynamic studies suggested the spontaneous and exothermic nature of PTPSS system. The ion exchange adsorbent shows ion exchange capacity for Li+, Na+, and K+ ions have been found to be 1.75, 2.24, and 2.41 meq/g, respectively. Its selectivity was examined by achieving some important binary separations like Pb2+- Cd2+, Pb2+- Hg2+, Pb2+- Cu2+, Pb2+- Zn2+, Pb2+- Ni2+, and Pb2+- Fe3+ on its column. On the basis of distribution studies (Kd values), PTPSS was highly selective for Pb(II). Therefore, the hybrid cation exchange material PTPSS can be used as a potential ion exchange material for the selective separation of Pb(II) ion in environmental remediation.

Hybrid Proton-Exchange Membrane Based on Perfluorosulfonated Polymers and Resorcinol-Formaldehyde Hydrogel.

Organic resorcinol–formaldehyde (RF) hydrogels were introduced into a hybrid cation-exchange membrane in order to enhance its following properties: water uptake, thermal stability, and ionic conductivity. This study was aimed to investigate the modifications induced by the RF organic clusters that form a uniform distributed network within the perflourosulfonated acid (PFSA) matrix. RF concentration was controlled by resorcinol and formaldehyde impregnation time using water or ethanol solvents. The specific morphological and structural properties were characterized by atomic force microscopy, UV–Vis, and Fourier transform infrared spectroscopy. Thermo-gravimetric analysis was employed to study the thermal stability and degradation processes of the composite membranes. Proton conductivity, as a function of relative humidity (RH) at 80 °C, was measured using in-plane four-point characterization technique. Compared to the pristine membrane, the PFSA–RF hybrid membranes showed improved thermal stability at up to 46 °C and higher ionic conductivity for low RF content, especially at low relative humidity, when using ethanol-based solvents. Single fuel cell testing on RF-based membrane–electrode assembly revealed impeccable fuel crossover and power performance at 80 °C and 40% relative humidity, delivering a 76% increase in power density compared to a reference assembled with a pristine membrane and the same catalyst loadings.

Fluoride removal by hybrid cation exchanger impregnated with hydrated Al(III) oxide nanoparticles (HCIX-Al) with novel closed-loop recyclable regeneration system

A high concentrations of fluoride (F-) in groundwater limits drinking water supplies and results in fluorosis for hundreds of millions of people globally. A novel F- selective adsorbent (HCIX-Al) with a closed-loop regeneration system was developed, characterized, and assessed for its effectiveness in F- removal using both synthetic and natural groundwater. The system used an inexpensive polymeric macroporous cation exchanger doped with hydrous aluminum oxide (HAlO) nanoparticles. The HAlO nanoparticles were loaded into the matrix of the polymer phase by ion-exchange reactions between Al3+ and Ca2+ ions that bind with sulfonic acid functional groups of the cation exchangers. Hydrogen ions were generated in-situ during the HAlO formation process, creating acidic conditions inside the polymeric phase, which significantly increased F- sorption capacity (maximum sorption capacity = 5.75 mg/g at pH 7.5). While most other aluminum oxide-based F- selective sorbents suffer from low F- removal capacity at neutral to alkaline pH of typical groundwater, the HCIX-Al exhibited high F- sorption capacity even using alkaline (pH 8.5) groundwater. The treated water had a pH greater than 6.5 and non-detectable levels of aluminum (detection limit 0.002 mg/L), which complies with drinking water regulations. The HCIX-Al material can be reused by conditioning the exhausted material with a closed-loop regeneration chemical containing a recyclable 12% AlCl3 solution. The F- was precipitated from the regeneration system as CaF2 using lime at pH 11. This material, including a novel regeneration scheme, offered high F- removal capacity, cost-effectiveness, and provided a sustainable defluoridation process.

Novel Silica Functionalized Monosodium Glutamate/PVA Cross-Linked Membranes for Alkali Recovery by Diffusion Dialysis

In this work, two types of silica functionalized monosodium glutamate (GMSG and VMSG)/poly(vinyl alcohol) (PVA) were cross-linked by sol–gel process to prepare novel hybrid cation exchange membranes. The prepared membranes were systematically characterized by FTIR spectroscopy, SEM analysis, ion exchange capacity (IEC), TGA, water uptake, water swelling, mechanical strength and diffusion dialysis performance for alkali separation using NaOH/Na2WO4 solution. The FTIR peaks around 1260–1350 cm− 1 confirmed the secondary C–N linkages. The cross-linking between GMSG/VMSG and PVA was verified by the presence of stretching peaks of Si–O–C, Si–O–Si, C–O–C and –C(=O)–O–C groups between 1080 and 1120 cm− 1. SEM analysis confirmed dense structure and uniform distribution of silica particles in the membrane. TGA results indicated that GMSG membranes showed relatively high thermal stability as compared to VMSG membranes. Water uptake and degree of swelling decreased while IEC values increased with the increase of GMSG/VMSG content in membrane matrix. The mechanical properties of the membranes improved up to 40% GMSG/VMSG content. The NaOH dialysis coefficient (UOH) values improved while values of separation factor (S) declined with the increase of GMSG/VMSG content. Finally, the effect of temperature was studied and it was found that increase in temperature from 25 to 45 °C resulted in increase of diffusion coefficient and decrease of separation factor for both GMSG/VMSG crossed-linked with PVA membranes.

Синтез нанокомпозита гидроксид хрома (III) – катионообменник КУ-2-8

Работа посвящена получению нанокомпозита гидроксид хрома (III) – катионообменник по-средством включения Cr(OH)3 в матрицу сильнокислотного катионита. Гидроксидсодержащий ги-бридный катионообменник синтезировали на основе полимерного носителя с сульфоновокислыми ионообменными группами КУ-2-8, поэтапно переводя функциональные группы из натриевой в Сr3+-форму и осаждая гидроксид хрома (III) в зерно катионообменника раствором щелочи NaOH. Содер-жание хрома в нанокомпозите определяли по концентрации вышедших в раствор противоионов мето-дом прямой потенциометрии. Морфологию поверхности гибридных хром-полимерных гранул иссле-довали методом сканирующей электронной микроскопии. Элементный анализ состава скола нано-композита определяли методом рентгеновского энергодисперсионного микроанализа. Найдено, что поверхность гибридной гранулы однородна. Сера и натрий достаточно равномерно распределены по всему объему полимерных гранул за исключением внешнего слоя, обедненного этими элементами. Хром обнаружен не только в поверхностном слое гранулы толщиной 10–15 мкм, но и в объеме зерна, где его концентрация существенно ниже. Распределение хрома по объему зерна является неравно-мерным. Показано, что при переходе от периферии зерна к центру концентрация хрома экспоненци-ально снижается. Элементное картирование подтверждает, что хром находится в грануле катионооб-менника в окисленной форме. Предложен механизм формирования нанокомпозита гидроксид хрома (III) – катионообменник КУ-2-8 с сульфоновокислыми ионообменными группами. В ходе реакции ионообменного насыщения происходит переход ионита в Cr3+-форму. При подщелачивании реакци-онной среды осадок гидроксида хрома (III) локализуется вблизи поверхности катионообменника. Формирование осадка Cr(OH)3 в наноразмерных порах катионита препятствует диффузионному пере-носу ионов Cr3+ по направлению к его поверхности, в то время как Доннановское исключение не поз-воляет гидроксильным ионам в достаточной концентрации проникнуть достаточно глубоко в объем гранулы ионита. Показана возможность получения наночастиц модификатора (гидроксида хрома (III)) с неравномерным распределением в объеме гранулы, объединенных в агломераты микрометро-вого размера.

A comparative study of ion exchange behavior and analytical applications of zirconium and tin based polyaniline hybrid cation exchangers

The present work reports the synthesis, characterization and ion exchange properties of polyaniline based hybrid cation exchangers such as polyaniline‑zirconium(IV) tungstate (PA/ZrW), polyaniline‑zirconium(IV) tungstomolybdate (PA/ZrWMo), polyaniline‑tin zirconium molybdate (PA/SnZrMo) and polyaniline‑tin cerium molybdate (PA/SnCeMo). The structural characterization and morphology of the hybrid cation exchangers were done by FT-IR, XRD, SEM-EDS and UV–Vis studies. Thermal stability of hybrid cation exchangers was analyzed by TGA study. The order of ion exchange capacity for alkali and alkaline earth metal ions on the synthesized hybrid materials was found to be in the sequence K+ > Na+ > Li+ for alkali metals and Ba2+ > Sr2+ > Ca2+ > Mg2+ for alkaline earth metals. The distribution coefficient of metal ions in de-mineralized water and different concentrations of HNO3, effect of pH, adsorbent dose, drying temperature and concentration of Pb2+ on Kd value were also investigated. It is clear from the distribution studies that all the hybrid cation exchange materials have more selectivity towards toxic metal ion, Pb2+ and Cd2+ and least affinity towards Zn2+, Co2+, Cu2+, Mg2+ and Ni2+ ions.

Perfluorinated hybrid membranes modified by metal decorated clay nanotubes

A number of one-layer perfluorinated cation-exchange membranes modified by halloysite clay nanotubes were prepared using two different solvents: dimethylformamide and isopropanol. The modifier is hybrid Pd, Pt/clay nanotubes doped at 4 wt % into the polymeric matrix. Metal nanoparticles of platinum or palladium were deposited onto the surface of the nanotubes then embedded into membranes providing composite materials which are promising for solid polymer fuel cells.At the first time the distribution of water, effective pore radius, electrical conductivity, selectivity, diffusion and electroosmotic permeability, contact angles (hydrophilicity/hydrophobicity) were investigated for the presented different types of nanocomposite membranes. It is shown that hybrid cation-exchange membranes demonstrate improved thermal, mechanical and transport properties synergistically combining separation. The optimized halloysite-perfluorinated polymer membranes meet the conditions for electro-transport properties needed for solid electrolytes in separation diaphragms for low-temperature membrane electrolyzers. Introduction of Pt-halloysite into the perfluorinated matrix results in preservation of high selectivity and constant value of the limiting electrodiffusion current density.Comparing the theoretically calculated parameters, like the limiting current density, selectivity, transport numbers of water to the experimentally measured ones for samples we can conclude that the hybrid membrane with platinum nanoparticles is promising for nanocomposite cation-exchange perfluorinated films both as the separating membrane in fuel cells and other electric devices.

Hybrid Cation Exchange Membranes with Lithium Ion‐Sieves for Highly Enhanced Li+ Permeation and Permselectivity

Hybrid Cation Exchange Membranes with Lithium Ion‐Sieves for Highly Enhanced Li⁺ Permeation and Permselectivity

Hybrid Cation Exchange Membranes with Lithium Ion‐Sieves for Highly Enhanced Li+ Permeation and Permselectivity

AbstractCation exchange membranes (CEMs) hold promise for efficient and environment‐friendly lithium extraction from salt‐lake brine. However, development and practical application of CEMs are significantly hindered by the low Li+ permeation and permselectivity. Herein, novel hybrid CEMs are developed by dispersing lithium ion‐sieves (LMO) into sulfonated poly(ether ether ketone) matrix. Two kinds of LMOs are synthesized including acidified LMO (HMO) and its sulfonation compound (HMO‐S). The physicochemical property and separation performance of hybrid membranes are systematically investigated. The uniformly dispersed HMO and HMO‐S enhance the thermal, mechanical stability, and swelling resistance of hybrid membranes. Furthermore, these fillers obviously reduce the area resistance from 8.0 to less than 6.0 Ω cm−2. Importantly, the unique Li+ transfer channels in HMO/HMO‐S efficiently elevate the Li+ permeation by up to 66%. While the “ion‐sieve effect” of the channels weakens the migration of Mg2+ and K+, thus notably rising Li+/Mg2+ and Li+/K+ permselectivities by ≈5 times, which is difficult to realize with conventional fillers. Comparing with HMO, HMO‐S shows higher improvement for permselectivity because of the reduced area resistance of the resultant hybrid membrane. This study paves a way to design and development of selective Li+ exchange membranes for transport and separation applications.

Crosslinked PVA-based hybrid membranes containing di-sulfonic acid groups for alkali recovery

Hybrid cation exchange membranes (CEMs) are prepared from polyvinyl alcohol (PVA), 3-mercaptopropyltriethoxysilane (MPTES) and benzaldehyde disulfonic acid disodium salt (BADSANa), which contains several functional groups like –OH, –SH/ –Si(OC2H5)3 and –SO3Na/ –CHO, etc. The availability of –CHO and –Si(OC2H5)3 groups are of immense importance as they can be easily cross-linked with PVA–OH groups through the acetal and sol-gel reaction. The -SH groups are further oxidized into the –SO3H groups in the presence of Fenton’s reagent or ozone to make the membrane matrix charged. It has been observed that membrane hydrophilicity and ion exchange capacities gradually increase with the dosage of BADSANa and MPTES. The tensile strength of prepared membranes is in the range of 5.8–30.9 MPa while the elongation at break (Eb) of 118.9–447.2%. The short-term thermal stability is ranged between 165 and 275 °C. The alkali resistance is acceptable at room temperature. Diffusion dialysis (DD) process shows that if the prepared membranes are oxidized by Fenton’s reagent, the dialysis coefficients of NaOH (UOH) in NaOH /NaAlO2 solution are in the range of 2.8–23.4 mm/h along with the separation factors (S) in between 4.6 and 20.0. The optimized membrane (M6B2-F) has both the highest S value of 20.0 and UOH as 23.4 mm/h. The similar separation performance can be achieved if the membranes are oxidized by ozone instead of Fenton’s reagent. The ozone oxidation, the organic solvent free preparation, and the favorable DD performances may provide new clues for designing new cation exchange hybrid membranes for alkali recovery.

A Novel Hybrid Poly (vinyl alcohol) (PVA)/Poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) Membranes for Reverse Electrodialysis Power System

The ion exchange membrane (IEM) is a primary component in the reverse electrodialysis (RED) system for salinity gradient power generation. A great challenge exists in the selection of appropriate membrane materials and the design of proper RED membranes to optimize such an energy-producing process. This work presents a novel and cost-effective method for preparing hybrid cation exchange membranes by incorporating two organic polymers with fine film-forming ability. The functionalized poly (2,6-dimethyl-1,4-phenylene oxide) (sPPO) polymer with sulfated polyvinyl alcohol (sPVA) is proved to have great potential as a candidate for applications in RED. The prepared membranes showed that an optimal range of sPVA (2–10wt%) improved the permselectivity (up to 87%) and an area resistance (down to 1.31Ω cm2), which is comparable to those obtained with commercially available FKS (Fumasep®, Germany) membranes. The hybrid membrane containing 5wt% of sPVA achieved the highest gross power density at 0.46W/m2. This study shows the potential of using organic-organic hybrid membranes for the RED power generation system.

Synthesis, Characterization and Performance Validation of Hybrid Cation Exchanger Containing Hydrated Ferric Oxide Nanoparticles (HCIX-Fe) for Lead Removal from Battery Manufacturing Wastewater

This study is aimed to synthesize, characterize and validate the performance of a novel hybrid nanoadsorbent for selective removal of lead from a battery manufacturing wastewater. The hybrid nanosorbent, named as HCIX-Fe, was prepared by impregnating hydrated Fe (III) oxide (HFO) nanoparticles inside polymeric cation exchange resin containing negatively charged sulfonic acid (-SO3-) fixed functional groups. HCIX-Fe was characterized by SEM-EDX and XRD to confirm the distribution and determination of phase of HFO dispersed inside the hybrid nanosorbent. Fixed-bed column runs with HCIX-Fe beads were carried out using wastewater from a battery manufacturing plant. The wastewater had a pH of 1.8 and contained of 3.5 mg/L of Pb2+ coexisted with 250 mg/L Ca2+ ions. The results have shown that HCIX-Fe column could treat lead-contaminated water up to 6,500 bed volumes (BVs) before the occurrence of breakthrough concentration of 0.2 mg/L Pb2+ resulting in a removal capacity of 6.85 mg Pb2+/ml of the HCIX-Fe bed. Under similar condition, adsorbent columns with cation exchange resin (C100), granulated activated carbon (GAC) and granulated activated carbon impregnated with HFO (GAC-Fe), could treat the same wastewater only until 400, 900 and 1,500 BVs, respectively. When compared with the parent adsorbents, impregnation by HFO greatly enhanced the Pb2+ removal capacity of C100 and GAC by 1,625% and 167%, respectively. Both HFO and high density of sulfonic acid (-SO3-) in the host cation exchanger are individually capable of selective removal of Pb2+ ions; however the hybrid material demonstrated a synergistic effect for Pb2+ removal through the Donnan Membrane effect. Due to amphoteric behavior of HFO, the HCIX-Fe could be regenerated and reused with 10 BVs of 2% HNO3 and 1% FeCl3·6H2O solution.

Turmeric/polyvinyl alcohol Th(IV) phosphate electrospun fibers: Synthesis, characterization and antimicrobial studies

Turmeric/polyvinyl alcohol (PVA) thorium(IV) phosphate hybrid cation exchange nanofibers were prepared for wastewater treatment along with antimicrobial activity. The physicochemical properties of electrospun fibers like thermal stability, surface morphology and composition were evaluated by using thermogravimetric analysis/differential thermal analysis/differential thermogravimetry (TGA/DTA/DTG), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transforms infra red (FTIR), and energy dispersive X-ray (EDX) techniques. The ion exchange capacity determined by volumetric analysis was found to be 1.98meq dry/g of ion exchanger. Antimicrobial properties of turmeric/PVA Th(IV) phosphate hybrid cation exchange electrospun fibers were validated by agar-well diffusion test (ADT) and microtitre plate assay (MPA) analyses. The presence of turmeric in polyvinyl alcohol Th(IV) phosphate hybrid cation exchange nanofibers is responsible for antimicrobial properties. The maximum zone of inhibition was found to be 22mm for E. coli at 50µg/ml and 21mm for S. aureus at 100µg/ml.

New approach to characterization of hybrid nanocomposites

This paper presents a novel approach to the characterization of hybrid cation-exchange membranes by applying the “fine porous membrane” model. We verify this approach using samples of cation-exchange membranes synthesized on the base of the perfluorinated MF-4SC membrane and halloysite nanotubes and prepared by the casting method. For characterization we use the initial pure MF-4SC membrane and two hybrid membranes MF-4SC spatially modified with halloysite nanotubes encapsulated by Pt nanoparticles or intercalated by Fe nanoparticles. Based on our own experimental data for the diffusion permeability and specific conductivity in dependence on electrolyte concentration (HCl), we calculate the main physico-chemical parameters of these membrane systems, i.e. the ambipolar diffusion and equilibrium distribution coefficients of the electrolyte inside the membrane. Comparing the theoretically calculated parameters to the experimentally measured current-voltage curves, selectivity, transport numbers of cations and water for all the three samples we conclude that the hybrid membrane with platinum nanoparticles is superior to the other two membranes as far as fuel cells are concerned.

Development of PVA/MIDA based hybrid cation exchange membranes for alkali recovery via Diffusion Dialysis

Abstract We report poly vinyl alcohol (PVA) based hybrid membranes composed of methyl iminodiacetic acid (MIDA) and tetraorthoethoxysilane (TEOS) prepared by classical sol–gel process. MIDA was prepared via N-methylation of iminodiacetic acid and then successfully incorporated into the PVA backbone. The concentration of MIDA with respect to PVA was varied from 10 to 40 wt%. These hybrid membranes showed water uptake (WU) in the range of 106–125%, ion exchange capacities (IECs) of 1.14–2.13 mmol/g, dialysis coefficient (UOH) from 0.009 to 0.012 m/h as well as selectivity (S) from 16.0 to 19.9. These obtained results revealed that MIDA. It controls the hydrophilicity and ion exchange capacity by providing channels for the transportation of ions through carboxylate sites. PVA/MIDA hybrid membranes also showed good thermal stability with the initial thermal decomposition temperature (IDT) ranging around 150–160 °C and excellent mechanical properties such as tensile strength (TS) of 9–25 MPa and elongation at break (Eb) of 32–150%.