Composite Cation Exchange Research Articles

Development and analysis of the physical and electrochemical characteristics of a nano titanium (IV) tungstomolybdate supported on polyethersulfone composite cation exchange membrane

In this study, a series of novel composite membranes were synthesized utilizing polyethersulfone (PES), sulfonated polyethersulfone (SPES) as base polymer and titanium tungstomolybdate (TWM) as an inorganic ion exchange resin. The membranes were fabricated through the solution casting technique. The composite membranes exhibited enhanced thermal and chemical stability, as well as improved oxidative stability. All the composite membranes demonstrated higher hydrophilicity, with the SPES-TWM composite membranes displaying the lowest contact angle of 65°. The composite membranes also displayed favorable water uptake (up to 26% for SPES-TWM) and lower methanol uptake (maximum 12% for SPES-TWM) and better mechanical stability (maximum of 40 MPa for SPES-TWM). The SPES-TWM composite membranes exhibited the maximum ion exchange capacity of 1.32 meq.g−1. The transport number of 0.95 was obtained for SPES-TWM, which is comparable to the Nafion-117 membrane. The proton conductivity of both membranes increased as the temperature increased. The maximum proton conductivity of 6.3 mScm−1 was observed for SPES-TWM at 60 °C.

Synthesis of potassium-zinc hexacyanoferrate and their SPEEK composite cation exchange membranes for selective recovery of cesium from aqueous system

Potassium-Zinc hexacyanoferrate adsorbent was prepared by precipitation method and further its composite membrane has been fabricated using sulphonated poly (ether ether ketone) (SPEEK) to investigate cesium (Cs+) recovery from aqueous media. The formation of desired adsorbent material was confirmed by Powder X-ray diffraction (PXRD) while chemical structure was assessed by Fourier-transform infrared spectroscopy (FT-IR). The BET surface area, pore volume and pore diameter found as 298.6 m2/g, 0.1034 cm3/g and 3.04 nm respectively calculated by Brunauer and Emmett and Teller (BET) surface area analyzer. The adsorbent synthesized was observed to work efficiently with maximum adsorption capacity of 54.64 mg Cs/g of adsorbent for Langmuir isotherm model. There was no effect of competing ion (Na+, K+, Mg2+, Ca2+) on adsorption performance during Cs+ removal. Cs+ recovery from the aqueous system in presence of 1000 ppm NaCl was performed using SPEEK composite membrane by electrodialysis. Observing the electrodialysis performance, composite membrane exhibited a high removal/recovery for Cs+ ions than Na+, K+, Mg2+ and Ca2+. The composite membrane exhibited a remarkable removal efficiency for Cs+ ion, which is 33.85 times larger than pristine SPEEK membrane. These results confirm composite membrane as promising candidate for the selective recovery/removal of cesium ions from aqueous solution in existence of intrusive ions and can effectively be applicable for industrial applications.

Sol-gel synthesis, physico-chemical characterization and investigations on ion exchange performance of atypical conducting polymer integrated composite cation exchangers

ABSTRACT Herein, an effective sol-gel strategy was utilized for the synthesis of atypical Polypyrrole/EDTA-Zirconium(IV) phosphate (PYZP) and Polypyrrole/EDTA-Zirconium(IV) iodate (PYZI) composite cation exchangers. The structural aspects, surface morphology, elemental composition and thermal constancy of the aforementioned composite cation exchangers were scrutinized through UV-Visible, FT-IR, XRD, SEM with EDAX, TEM and TGA studies. As-prepared conducting polymeric composite materials divulged not only excellent ion exchange capacity but also better thermal stability, electrical conductivity and notable selectivity toward Pb(II) ions as compared to their individual inorganic moieties. The improvement in ion exchange capacities (IEC) for distinct alkali metal ions of PYZP composite cation exchanger were Li+, 2.89; Na+, 3.15; K+, 3.34 meq/g and PYZI composite cation exchanger were Li+, 2.60; Na+, 2.86; K+, 3.21 meq/g, separately. It was concluded that PYZP composite acts as an excellent cation exchanger compared to PYZI composite due to the presence of ionogenic phosphate anions. The partition competency of the composite materials toward distinct metal ions in diverse solvent systems exposed the separation potentials of metal ions of systematic prominence from a specified binary combinations encompassing Cd(II) – Pb(II), Hg(II) – Pb(II), Cu(II) – Pb(II), Zn(II) – Pb(II), Ni(II) – Pb(II) and Fe(III) – Pb(II) metal ions. Subsequently, the conducting competency was examined through AC-Impedance spectroscopy.

Synthesis and ion exchange properties of the new composite cation exchanger polypyrrole tin boratophosphate

Synthesis and ion exchange properties of the new composite cation exchanger polypyrrole tin boratophosphate

Synthesis and Characterization of Composite Cation Exchanger Tin(IV) Boratophosphate and Comparison of Ion-Exchange Properties

Synthesis and Characterization of Composite Cation Exchanger Tin(IV) Boratophosphate and Comparison of Ion-Exchange Properties

Potentiometric Determination of Mercury Ions by Sol-gel Synthesized Multi-walled Carbon Nanotubes Zr (IV) Phosphate Composite Fabricated Membrane Electrode

Background: The nanocomposites are formed by introducing inorganic nano-clusters, fullerenes, clays, metals, oxides with numerous organic polymers. The assembly of these materials exhibits better properties such as catalytic, thermal stability and adsorption properties, etc. than the individual materials. Objective: The nanocomposite synthesized here by sol-gel method was primarily evaluated for cation exchange properties viz, elution concentration, elution behavior, effect of temperature on ion-exchange capacity. The synthesized composite was used as an electro-active component for fabrication of Hg2+ ion selective membrane electrode. Method : The sol-gel technique was used to synthesize multi-walled carbon nanotubes Zr(IV) phosphate composite cation exchanger. By the technique of solution casting the material as an electroactive part was used for the fabrication of mercury ion-selective membrane electrode. The potential response of the electrode was also investigated as a function of membrane composition and plasticizer. Results: The composite cation exchanger exhibited 1.8 meq g-1 ion-exchange capacity (IEC). It retained almost 65 % of its initial IEC upto a temperature of 400 °C. Distribution studies showed the selective nature of the composite for Hg(II) ions. The ion-selective membrane electrode exhibited typical Nernstian response towards Hg2+ ions in the concentration range 1×10-1 -1×10-7 M. Conclusion: The results discussed reveal that a new cation composite exchanger-multi-walled carbon nanotubes Zr (IV) phosphate exhibited excellent cation exchange properties and was found to be preferentially selective towards the Hg2+ ions. It was also used as an indicator electrode in the titration of Hg2+ using ethylenediaminetetraacetic acid as a titrant.

Caustic production from industrial green liquor using alkali resistant composite cation exchange membrane

Kraft paper industries perform causticization (NaOH production) by fresh lime (CaO) addition in green liquor (rich in sodium carbonate) resulting calcium carbonate (CaCO3) as precipitate, which is washed, dried and calcined at ~900 °C to regain CaO, making the process energy intensive and environmentally polluting. Current investigation reports electro-electrodialysis (EED) based conversion of green liquor to NaOH using alkali resistant composite membrane made from graphene oxide (GO) and SPK [sulfonated poly (ether ether ketone)]. Using optimized process parameters: current density (60 mA·cm−2), flow rate (2.0 L·h−1), 25 °C, and batch recirculation of 0.5 L of green liquor through EED set up (66 cm2), resulted 0.5 L (2.35 mol·L−1). Corresponding current efficiency and energy consumption estimates were ~67.9% and ~0.126 kW·h·mol−1 respectively. After thirty batches of experiment, the performance of NaOH production and its energy consumption remains unaltered. Performance in house membrane was compared with commercial (FKB-PK-130). Cost estimation based on lab-scale data for treatment of 50,000 L/day of green liquor through conventional and EED technique showed ~$2050 per day without solid waste generation and environmental pollution.

Porphyrin thin-film composite cation exchange membranes enable high retention of amino acids in electrodialysis

In order to improve the retention of amino acids in desalinating a saline stream using electrodialysis, a novel porphyrin-containing thin-film composite (TFC) cation exchange membrane was prepared by interfacial polymerization (IP) using tetraphenylporphinesulfonate (TPPS), m-phenylene diamine (MPD), and trimesoyl chloride. The separation of a single amino acid [Arginine (Arg), Lysine (Lys), Histidine (His), and Proline (Pro)] and the mixture of four from a NaCl solution was investigated. Results showed that sodium ions transported much faster than the amino acid ions due to its small molar mass and high mobility. Arg migrated much faster than Lys may attribute to its guanidine that increased the polarity of the ion, thus resulting in a higher loss degree of Arg (60%) than that of Lys (32%) in the single amino acid test. In the mixed amino acid test, a competition behavior between Arg and Lys limited their transport over membrane. The loss degree of Arg and Lys was reduced to 32.7% and 9.31% with porphyrin TFC membrane, which could be attributed to combination of the TFC dense layer and the strong electrical interaction between the charge-elevated membrane surface and the amino acids. The porphyrin TFC achieved a loss degree of total amino acids of 13.8%, which was much lower than that of pristine TFC membrane (20.2%) and based membrane (27.25%), respectively. These findings indicated that using porphyrin TFC membrane can efficiently separate salts and amino acids, and may also be beneficial for other membrane separation techniques.

Sulfonated poly (ether ether ketone) composite cation exchange membrane for NaOH production by electro-electrodialysis using agro-based paper mill green liquor

Causticizing process of pulp and paper mills, is highly energy intensive and environmentally unsafe. We report environmental friendly electro-electrodialysis (EED) process using in-house prepared cation exchange membranes (CEMs) for NaOH production from green liquor solution (GLS) of agro-based paper mills. Different composite CEMs with varied composition of sulfonated graphene oxide (SGO) incorporated sulfonated poly (ether ether ketone) (SPK) were synthesized. Best optimized CEM (SPK-3 with 3.0 wt% SGO loading) exhibited 1.75 mmol·g−1 cation exchange capacity, 32.01% water uptake, 11.41% swelling ratio, conductivity 0.037 S·cm−1, and 0.97 counter-ion transport number with high alkaline and thermo-mechanical stabilities. Industrial GLS was used for NaOH production by EED at 60 mA·cm−2current density. Optimized SPK-3 membrane produced 1.17 mol·L−1 of NaOH with 61.4% current efficiency (η), and 2.58 kW·h·kg−1 energy consumption (EC) during 4 h of EED process. Under similar operating conditions, pristine (SPK), and commercial CEM (FKB-PK-130), showed inferior performance. Longevity of SPK-3 CEM was assessed with industrial GLS for fifty cycles of EED experiments 4 h duration each. Reported results are promising for sustainable NaOH production from industrial GLS of pulp and paper mills, and provide a resourceful alternate for industrial waste.

Potential utility and design approach on novel mesoporous polyaniline functionalized ternary composite cation exchanger

A mesoporous polyaniline functionalized novel ternary composite cation exchanger was synthesized via sol-gel mixing of polyaniline (PANI) into the matrices of EDTA-Zirconium(IV) iodate (EZI). The PANI/EDTA-Zirconium(IV) iodate(PEZI) composite cation exchanger was found to be good ion exchange capacities (IEC) for different alkali metal ions were: Li+, 2.09; Na+, 2.34; K+, 2.63 meq/g and higher thermal stability. Distribution studies (Kd values) inferred that the cation exchanger becomes highly selective for Pb(II) ions than Hg(II) and Cd(II) ions, respectively and its selectivity was arrested by some analytically and industrially important binary mixtures, viz. Cd(II)– Pb(II), Hg(II)– Pb(II), Cu(II)– Pb(II), Zn(II)– Pb(II), Ni(II)– Pb(II), Fe(III)– Pb(II), etc. on its column. The physico-chemical characterizations as well as the properties of the composite cation exchange material were also determined using UV-Visible, FT-IR, XRD, SEM with EDAX, TEM, BET and TGA studies. The AC-Electrical conductivity of PEZI composite cation exchange material was also studied. The analytical utility of the proposed composite cation exchange material has been successfully employed for the removal of Pb(II) ions from waste water streams.

Synthesis of novel PANI-based Ti(IV) phosphosulphosalicylate composite cation exchanger — structural, electrical, and impedance properties

In order to combine the properties of inorganic ion exchanger and conducting organic polymer, a new class of organic–inorganic composite cation exchanger PANI–Ti(IV) phosphosulphosalicylate (PTPSS) was synthesized by intercalating polyaniline (PANI) into Ti(IV) phosphosulphosalicylate (Ti(IV) PSS) using sol–gel chemical route with enhanced properties. PTPSS has been characterized by using Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDAX), thermo gravimetric analysis (TGA-DTG), and Transmission Electron Microscopy (TEM). Ac electrical conductivity studies were also performed. This material possessed electrical conductivity of [Formula: see text] – [Formula: see text] [Formula: see text]which falls in the semiconducting range. The frequency (2 × 105– 1 × 106Hz) dependent Ac conductivity at room temperature suggests the evidence for the transport mechanism for the conductivity in PTPSS. The structure of the composite cation exchanger extremely supports its conducting behavior.

Sulfonated poly ether ether ketone (SPEEK) based composite cation exchange membranes for salt removal from brackish water

Availability of fresh water is a serious concern due water pollution in these days. Several efforts have been made for water desalination where membrane based technology is considered prominently. Here, we synthesised sulfonated poly ether ether ketone (SPEEK) based functionalized hexagonal boron nitride (SBN) composite cation exchange membranes for water desalination. The morphology of BN and presence of sulfonic acid group are confirmed by TEM analysis. Ionic conductivity for SPEEK membrane is found to be 2.02 × 10−2 S. cm−1, which reaches to 4.05 × 10−2 S. cm−1 for SBN-10/SPEEK composite membrane. Ion exchange capacity of the SBN-10/SPEEK composite membrane also increased by 40 % and reaches to 1.66 meq.g-1 as compared to SPEEK membrane. Incorporation of SBN in membrane matrix not only improve the ion exchange capacity and ionic conductivity as well as expand the stability of the membranes. SEM micrograph confirm the uniform distribution of SBN in SPEEK membrane matrix. The composite membranes show the better ion transport properties in term of current efficiency and power consumption during salt removal from brackish water by electrodialysis. For SBN-10/SPEEK composite membrane power consumption was 0.75 kW h.Kg-1 with 98.5 % current efficiency.

Functionalized carbon dots composite cation exchange membranes: Improved electrochemical performance and salt removal efficiency

Here, we investigated the functionalized carbon dots as a possible organic filler for the sulfonated poly (ether sulfone) (SPES) based composite cation exchange membranes to improve the membrane performance. Sulfonated carbon dots (SCDs) are synthesised by simple pyrolysis of citric acid in presence of sodium 4-styrene sulfonate. Functionalized carbon dots provide excellent hydrophilicity, and affinity towards SPES due to the intra hydrogen bonding between sulfonic group of SPES and functionalized carbon dot. Addition of filler material leads to the improvement in physicochemical and electrochemical properties of the composite membranes. 32 % increment in ionic conductivity is noted after the addition of 2% SCDs for SMQ-2 membrane while ion exchange capacity goesets double. Membranes are evaluated for salt removal from brackish water by electrodialysis and found that SMQ-2 membrane showed 30 % reduction in the power consumption than the SM membrane. Composite membranes can efficiently be used for the salt removal from brackish water.

Modified composite cation exchange membrane with enhanced stability and electrochemical performance

Herein, we elaborated on the feasibility of coupling polyvinyl chloride with tin aluminium molybdophosphate to form composite membranes that facilitate enhanced electro-transport properties. Additionally, the effect of appropriate material selection on attaining excellent stability and selectivity of a membrane was investigated, and the membrane with 25% polymer had the best results in terms of improved ion exchange capacity, water uptake, porosity, membrane potential, and chemical and thermal stabilities. The electrochemical properties of the membrane that had the most stable polymer ratio were evaluated according to the membrane potential and fixed charge density measurements using different 1:1 ratios of electrolytes with various concentrations (1 M to 0.01 M). The membrane potential, transport number, and mobility ratio of the electrolytes from the highest to lowest were NaCl > KCl > NaNO3 > KNO3.The measured membrane potentials closely agreed with the theoretical predictions from a mathematical model called the Toerell, Maeyer, and Siever (TMS) model, confirming efficiency and selectivity.

Sulfonated poly (ether ether ketone) composite cation exchange membrane for selective recovery of lithium by electrodialysis

Lithium is in demand since decades due to high applicability in batteries for electronic devices, which is expected to increase by 8 to 11% every year and Lithium ion battery market is estimated to grow to € 180 billion by 2024. Land deposits and seawater are two major sources of lithium but availability in sea water is higher than land. So an efficient technology is required to recover the lithium from sea water. Electrodialysis (ED) may be an alternate approach to recover the lithium from sea by selective ion exchange membranes. Here, Lithium selective ion exchange membranes have been synthesized by modification of sulfonated poly (ether ether ketone) (SPEEK) with lithium selective nanomaterial. Synthesized membranes were characterized for their chemical, structural and morphological structures and uniform dispersion of lithium selective nanomaterials. Composite membrane shows better lithium exchange capacity with excellent lithium conductivity as compared to SPEEK membrane. The adsorption of lithium (15.2 mg/g) found to be five times higher than that of Mg while recovery of lithium was 64% using electrodialysis process by NC-4 composite membrane. Selectivity factor for composite membrane were 4.82, 3.0 and 2.17 for Li/Mg, Li/K and Li/Na, respectively. The selective composite membranes can be suitable for Li-ion recovery from sea brine/bittern on large scale.

Fabrication of cation exchange membrane with excellent stabilities for electrodialysis: A study of effective sulfonation degree in ion transport mechanism

Composite cation exchange membranes (CEMs) based on sulfonated polyether sulfone (SPES) with low sulfonation degree (DS) have been prepared in our previous studies. The results provided an approach for the preparation of CEM with low cost, environment-friendly technology, and ideal properties. On the basis of the previous research, the first purpose of this study was aimed to explore more suitable hydrophilic additives to further improve CEM properties. Hydrophilic polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) with different molecular weight (Mw) were used as hydrophilic additives, while SPES was still used as the matrix material. The results showed that PEG was not a suitable additive for CEMs due to the low MW, while stability was clearly improved with increased PVP MW. Hence, for researchers, there is no need to waste time on PEG as a hydrophilic agent of CEM prepared with this method in the future. The second purpose of this study, which was the further optimization of the CEM performance, was achieved in the research of suitable hydrophilic additives. The results of stability and electrodialysis showed that SPES blended with PVP K90 was the best prepared CEM. The third purpose was the investigation of mechanism of synergistic effects between sulfonated groups and hydrophilicity on membrane properties. In this part, an innovative concept of effective DS was put forward. This innovative concept will directly impact on ion transport mechanism, and have a very important influence on the preparation idea of CEM. In conclusion, this study is of great significance for selection of CEM materials, improvement of membrane stability and further study of ion transport mechanism.

Manganese Vanadate and Polymethylmethacrylate Based Ion Exchange Materials: Synthesis, Characterization, and Selectivity in the Sorption of Eu and Co Radionuclides

A hybrid type of ion exchanger polymethylmethacrylate–manganese vanadate composite has been synthesized by mixing polymethylmethacrylate (PMMA) into inorganic material manganese vanadate. The physicochemical properties of this materials were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence spectrometry (XRF), infrared (IR), and thermal analysis (TGA and DTA).Thermal stability and distribution behavior were also studied to understand the cation-exchange behavior of the material. Sorption studies showed that the composite cation-exchanger has high selectivity to Eu(III) in comparison to other metal ions. Its selectivity was examined by achieving some important binary separations. The thermodynamic parameters such as ΔG*, ΔS*, ΔH*, and Ea have been calculated from the adsorption of Co(II) and Eu(III) onto polymethylmethacrylate–manganese vanadate composite and manganese vanadate and by using thermal decomposition behavior.

Sulfonated Poly(ether sulfone) based sulfonated molybdenum sulfide composite membranes and their applications in salt removal and alkali recovery

The adequate and potable water to meet present and future demand is much lower than the fresh water available. To fulfil the surplus demand of fresh drinking water, the management and treatment of waste water to be taken forward. In this view, electrodialysis (ED) has attracted immense attention nowadays to satisfy current water demands for drinking and industrial purpose. Ion exchange membranes are the cores of electrodialysis. Herein, composite cation exchange membranes are prepared for salt removal and water treatment using sulfonated poly(ether sulfone) (SPES) and sulfonated molybdenum sulfide (S–MoS2). Effect of S–MoS2 in membranes, water-related properties, ion transport, thermal and mechanical properties of synthesized composite membranes are evaluated. Incorporation of S–MoS2 in SPES enhance the performance of the membranes, and 5 wt % S–MoS2 composite membrane (DES-5) shows the 67% higher water sorption and 25% higher IEC compared to pristine SPES membrane. Their suitability is accessed in terms of salt removal via electrodialysis and alkali recovery via diffusion dialysis. The 5 wt % S–MoS2/SPES composite membrane exhibits 0.98 kWh/kg power consumption during salt removal that is 22% lower than 1.26 kWh/kg obtained for pristine SPES. Current efficiency towards salt removal and separation factor for alkali recovery for DES-5 membrane are 69.47% and 60.32, respectively, which are much higher than virgin SPES membrane.

Investigation of the effects of SPEEK and its clay composite membranes on the performance of Direct Borohydride Fuel Cell

In this study, composite cation exchange membranes (CEM) were developed. With the experience from widely studied proton exchange membrane fuel cells (PEMFC), sulfonated polyether ether ketone (SPEEK) was prepared to be a more effective and cheaper ionomer alternative to the industry standard Nafion ®. SPEEK polymer membrane can reach sufficient ionic conductivities but have some mechanical and chemical stability problems (at a high degree of sulfonations (DS)). Therefore, in order to optimize the membrane, composite mixing with a well-known organic/inorganic clays called Cloisite® 15A, Cloisite ® 30B and MMT were used. Test cells for both single-cell and conductivity were designed and constructed. The ionic conductivity cell was different than the ones used in most studies, measuring conductivity in-plane with 4 probes using EIS. The membranes were characterized for their proton conductivity with electrochemical impedance spectroscopy (EIS), for DS with H NMR, water uptake, and fuel cell performance tests. First results showed that the acidic sulfonic groups of SPEEK interacted with organic/inorganic clays and as a result of partial barrier the ionic conductivity was decreased but power densities were increased. SPEEK-Cloisite® 30B composite membrane has given 40 mW/cm2 power density value which is higher than pure SPEEK membrane (35 mW/cm2). The proton conductivities of the final composite membranes were close to bare SPEEK membranes which are 0,065 and 0,075 S/cm for SPEEK-Cloisite ® 30B and pristine SPEEK, respectively.

Promoting the electrochemical and separation properties of heterogeneous cation exchange membrane by embedding 8-hydroxyquinoline ligand: Chromium ions removal

In this probe, an attempt was made to remove the chromium ions using heterogeneous cation exchange membrane (HCEM) incorporated with 8-hydroxyquinoline (8-HQ) ligand as the chelating agent. Composite cation exchange membranes were provided by utilizing solution casting method. Computational study of resin particle and 8-HQ molecule also has been performed in order to accomplish detailed evaluation of their reactive properties. Molecular electrostatic potential (MEP) of 8-HQ molecule and resin particle showed that both particles have appropriate reactive sites for electrophilic and nucleophilic attack. Furthermore, interaction energy between 8-HQ molecule and resin particle were calculated which confirmed the presence of strong interactions between them. Elemental mapping, scanning electron microscopy (SEM), and scanning optical microscopy (SOM) images of the resultant membranes indicated a relatively uniform surface and particles distribution. Membrane water uptake and surface hydrophilicity were enhanced in the attendance of 8-HQ. The blended membranes demonstrated better selectivity (up to 95.5%), lower electrical resistance (∼5.8 Ω.cm2) and better ionic permeability compared to the bare one whereas the selectivity and electrical resistance of unmodified sample measured 77% and 14 Ω.cm2, respectively. The ligand modified membranes showed more dialytic rate in chromium ions removal (up to 74%) compared to bare membrane which could be assigned to strong affinity of 8-HQ in heavy metal ions adsorption.