Ion Exchange Applications Research Articles

Adsorption of strontium and caesium onto an Na-illite and Na-illite/Na-smectite mixtures: Implementation and application of a multi-site ion-exchange model

The application of a multi-site ion-exchange (MSIE) model to the prediction of contaminant behaviour onto soils or sediments requires a coherent adsorption database. Following the same approach exposed in preceding works on smectite (Siroux et al., Appl. Geochem. 87, 167; Wissocq et al., Appl. Geochem., 93, 167), a database is here implemented to allow modelling the adsorption of radionuclides 90Sr and 137Cs onto Na-illite, one of the major clay mineral encountered in the terrestrial environment. This database allows describing the adsorption properties of Sr2+ and Cs+ competing with major cations H+ — considered as the reference cation — and Na+ onto an Na-illite. To obtain the adsorption site capacities and selectivity coefficients of illite sites for Na+ towards H+, a saturation curve of Na+ on Na-conditioned illite was acquired. Adsorption isotherms issued from literature have been reinterpreted using the MSIE model to obtain the adsorption properties of Sr2+ and Cs+ onto purified and Na-conditioned illite. Afterwards, the predictability and robustness of the database were verified simulating experimental adsorption of Sr2+ and Cs+ onto Na-illite/Na-smectite mixtures.

Development of Pilot Scale System for Production of Polyamide-6 Fibers Grafted With Polymethacrylic Acid For Ion Exchange Applications

Removing the hazardous metals from wastewater especially industrial drainage is very important for preventing health problems in human beings, plants and animals. The ion exchanger has constructed as primary line of safeguards for that goal. In this study grafted polyamide-6 (PA-6) fibers with polymethacrylic acid (PMAA) was used as materials for the ion exchangers. Grafting was achieved under required time and temperature and the factors affecting the graft process were studied. The efficiency of the grafted fibers for adsorption of Cu2+, Pb2+ and Cr6+ was evaluated. The effect of adsorption parameters such as pH, duration of adsorption, initial ion concentration and the adsorption temperature on the degree of extraction (R %) and adsorption capacity (SC, mg/g) was studied. Optimization the conditions for the preparation on laboratory scale, adjustment and adaptation of these conditions to suit the production of these grafted fibers on pilot scale was accomplished.

Создание первых ионообменников и начало их широкого применения

Представлена история создания ионообменников с конца XIX в до середины XX века. Впервые проанализированы ключевые научные работы этого периода с историко-научной точки зрения. Расследованы ранее неизвестные факты биографии некоторых ученых. Проанализирован цикл работ, положивших начало ионообменной хроматографии

Novel Biohybrid Polysulfone Membranes with Physically Immobilized Gramicidin for Ion-Exchange Applications

The goal of this work was to design a system incorporating gramicidin (gA) into a polysulfone (Psf) membrane. The strategy involved immobilization of gA on the surface of two types of magnetite nanoparticles (MNPs) dispersed in a polymeric matrix. Membranes have been treated with surfactant Triton X100 (TRX) and surfactant/protein micelles (TRX/gA). MNP morphology was studied using transmission electron microscopy, and the chemical structure was confirmed by Fourier transform infrared analysis. Membrane morphology was observed under environmental scanning electron microscopy; water interactions were tested using static contact angle and water uptake, whereas ion transport was evaluated by means of a permeability test and current–voltage experiments. Depending on the type of nanoparticles used, immobilization led to either higher or lower membrane hydrophilicity but did not influence their morphology. Protein immobilization resulted in enhanced ion diffusion properties and membrane selectivity. This novel ...

Synthesis and Characterization of the Nano Particle Crystals of Sodalite Zeolite from agricultural waste

In this study, zeolite sodalite was synthesized from rice husk ash (RHA) by a simple conventional hydrothermal method using different time 1, 2, 3 and 4h. The best time for synthesizing is 4h. Rice husk (RH) was used as a source silicate to produce nanozeolite. The RHA silicate was obtained by combusting the RH at 700°C for 6h. Sodalite nanocrystals with crystallite sizes ranging from 35 to 44 nm have been synthesized from a sodium aluminosilicate solution at low temperature. A physical property of nanosized sodalite crystals were characterized by FTIR, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) method. BET was used to determine the average pore size distribution, pore volume and surface area. The results obtained from BET method proved that the average pore size in the mesoporous ranges, therefore it can be suitable for using in adsorption ion exchange and catalyst applications.

Cs-137 AND Co-60 CONCENTRATION REMOVAL ON RADIOACTIVE LIQUID WASTE BY ION EXCHANGE AND COAGULATION-FLOCCULATION METHOD

Radioactive liquid waste is a hazardous and toxic waste which comes from nuclear research laboratory. This waste may cause explosion when treated with evaporator. Aim: This research was intended to reduce and determine the best removal method of Cs-137 and Co-60 from radioactive liquid waste. Methodology and Result: Methods used in this research are ion exchange and coagulation-flocculation method. In ion exchange method used two types of reactor that is continuous reactor and batch reactor with variables of debit, material type, mesh size and mass of material, while in coagulation-flocculation method used jar test with ferro sulfate coagulant dose variables. Continuous reactor consisting of separating funnel and chromatography column with a diameter of 4 cm and height 60 cm, whereas in batch reactor used jar test stirrer. The application of radioactive liquid waste treatment is done using selected method, with the start condition for Cs-137 of 3 x 10-5 mCi/L and for Co-60 of 4.8 x 10-6 mCi/L. Application of Ion Exchanger with Continuous Reactor Speed 60 mL/10 sec and Coagulation-Flocculation with dose of 100 mmol/L in pH 8 effluent result the value for Cs-137 and Co-60 that undetected or very little, below 10-6 mCi/L. Conclusion, significance and impact study: The conclusion of this study is suitable with the Government Regulation Number 10 of 1997 about nuclear power, the limit of quality standard for Cs-137 and Co-60 is below 10-6 mCi/L. So the appropriate method to treat of Cs-137 and Co-60 are Ion Exchanger with Continuous Reactor Speed 60 mL/10 sec and Coagulation-Flocculation with dose of 100 mmol/L in pH 8.

Synthesis of Cellulose-graft-Polypropionic Acid Nanofiber Cation-Exchange Membrane Adsorbers for High-Efficiency Separations.

Fabrication of membrane adsorbers with elevated binding capacity and high throughput is highly desired for simplifying and improving purification efficiencies of bioproducts (biotherapeutics, vaccines, etc.) in the biotechnological and biopharmaceutical industries. Here we demonstrate the preparation of a novel class of self-supported, cellulose-graft-polypropionic acid (CL-g-PPA) cation-exchange nanofiber membrane adsorbers under mild reaction conditions for the purification of positively charged therapeutic proteins. In our fabrication method, acrylonitrile was first polymerized and surface grafted onto cellulose nanofibers using cerium ammonium nitrate as a redox initiator to form cellulose-g-polyacrylonitrile (CL-g-PAN). CL-g-PAN was then submitted to a hydrolyzation reaction to form CL-g-PPA cationic membrane adsorbers. Morphology and structural characterization illustrated the formation of CL-g-PPA membranes with uniform coating of polyacid nanolayers along the individual nanofibers without disturbing the nanofiber structure. Benefiting from these numerous cationic polyacid binding sites and inherent large surface area and open porous structure, CL-g-PPA nanofiber membrane adsorbers showed a lysozyme static adsorption capacity of 1664 mg/g of nanofibers. These membranes showed a lysozyme dynamic binding capacity of 508 mg/g of nanofibers at 10% breakthrough (equivalent to 206 g/L capacity), with a residence time of less than 6 s. Moreover, CL-g-PPA self-supported nanofibers displayed excellent structural stability and reversibility after several cycles of protein binding studies. This dynamic binding capacity of the CL-g-PPA nanofiber membranes was 3.2 times higher than that of macroporous cellulose membranes and 8.5 times higher than that of the Sartobind S commercial membrane adsorber. Considering the simple fabrication method employed, excellent protein adsorption capacity, remarkable structural stability, and reusability, CL-g-PPA nanofiber membranes provided a versatile platform for the chromatographic separations of biomolecules (e.g., proteins, nucleic acids, and viral vaccines) as well as water purification and similar ion-exchange applications.

Application of ion exchangers for the purification of galvanic wastewater from heavy metals

ABSTRACTThe aim of the present study was to investigate the sorption and physicochemical properties of the chelating ion exchangers with bis(2-pyridylmethyl)amine and aminophosphonic functional groups before and after the sorption of galvanic wastewaters. The study was carried out on the Dowex M4195, Lewatit® MonoPlus TP 220, Purolite S 940 and Purolite S 950 ion exchangers. For the practical use of the studied ion exchangers in the process of wastewater purification, the sorption capacity of the above-mentioned ions was determined depending on the phase contact time and sorption process in the whole volume of the beads.

Electroactive Nanoporous Metal Oxides and Chalcogenides by Chemical Design.

The archetypal silica- and aluminosilicate-based zeolite-type materials are renowned for wide-ranging applications in heterogeneous catalysis, gas-separation and ion-exchange. Their compositional space can be expanded to include nanoporous metal chalcogenides, exemplified by germanium and tin sulfides and selenides. By comparison with the properties of bulk metal dichalcogenides and their 2D derivatives, these open-framework analogues may be viewed as three-dimensional semiconductors filled with nanometer voids. Applications exist in a range of molecule size and shape discriminating devices. However, what is the electronic structure of nanoporous metal chalcogenides? Herein, materials modeling is used to describe the properties of a homologous series of nanoporous metal chalcogenides denoted np-MX2, where M = Si, Ge, Sn, Pb, and X = O, S, Se, Te, with Sodalite, LTA and aluminum chromium phosphate-1 structure types. Depending on the choice of metal and anion their properties can be tuned from insulators to semiconductors to metals with additional modification achieved through doping, solid solutions, and inclusion (with fullerene, quantum dots, and hole transport materials). These systems form the basis of a new branch of semiconductor nanochemistry in three dimensions.

Optimizing ammonium adsorption on natural zeolite for wastewaters with high loads of ammonium and solids

Ion exchange (IE) has been so far limited to treating waters and wastewaters low in solids (TS) and ammonium (NH4 +). This study provides a new insight into the application of IE for NH4 + removal from wastewaters with high NH4 + and TS, using natural zeolite as adsorbent medium. Assays were carried out in continuously stirred batch reactors to study the effect of initial NH4 +, pH, TS, contact time, and zeolite pore size (0.2–0.5 and 0.6–2.0 mm). Results confirmed the suitability of this zeolite to remove NH4 + from wastewater with high amounts of solids (up to 2%TS) and NH4 + (up to 2500 mgNH4 +-N/L). Ammonium adsorption capacity (q t ) was faster with 0.2–0.5 mm size because of the greater specific surface area and shorter diffusion path than 0.6–2.0 mm zeolite. Both zeolites showed increasing q t with increasing initial NH4 + due to the higher driving force produced by higher concentrations. The process followed a pseudo-second order kinetic and was best described by the Freundlich isotherm. Varying the pH (6–8.5) of the wastewater had no effect on NH4 + removal capacity. In conclusion, this natural zeolite showed high affinity for NH4 + in wastewater with high loads of NH4 + and solids, returning a viable treatment method when other techniques are not applicable.

Comprehensive investigation of physicochemical and electrochemical properties of sulfonated poly (ether ether ketone) membranes with different degrees of sulfonation for proton exchange membrane fuel cell applications

The investigation of the effect of various degrees of sulfonation (DS) is important for the selection and modification of hydrocarbon type membranes towards ion exchange applications. In this work, twelve kinds of sulfonated poly (ether ether ketone) membranes with different DS were prepared and their physicochemical and electrochemical properties were studied. The sulfonated polymers were prepared by sulfonation of PEEK and characterized by H NMR, FTIR, and XRD. Then, the different SPEEK membranes were prepared by the solvent casting method, and their morphology and homogeneity were investigated by FESEM. The effect of DS on the thermal (TGA and DSC), mechanical and oxidative stabilities, water uptake behavior, and ionic exchange capacity of the membranes was determined. Also, the proton conductivity of the membranes at different temperatures and relative humidities were measured. The results indicated that the SPEEK samples showed progressive deterioration of thermal stability, an increase of glass transition temperature, a decrease of the elastic modulus, and a decrease of the chemical stability with increasing of the DS. The proton conductivity of SPEEK membranes increased with DS, and for each membrane increased with increasing temperature and humidity. The results showed that moderate DS membranes (DS ∼ 65%) had acceptable mechanical, thermal, electrochemical, and chemical stability.

TÜRKİYE'DEKİ DOĞAL ZEOLİTLER VE İYON DEĞIŞİMİ UYGULAMALARI

Su ve atıksu arıtımında iyon değişimi prosesi özellikle ağır metallerin ve sertlik yaratıcı unsurların giderimi için kullanılmaktadır. İyon değişimi prosesinde genellikle sentetik olarak üretilen polimerik reçineler kullanılmaktadır. Böylelikle su ve atıksularda bulunan inorganik kirleticiler reçinenin yapısında bulunan fonksiyonel gruplara bağlanarak uzaklaştırılabilmektedir. Ancak kullanılan sentetik iyon değiştiricilerin maliyetleri bu yöntemin kullanımını sınırlandırmaktadır. Diğer taraftan iyon değişim prosesinde sentetik zeolitlere alternatif olarak görülen doğal zeolitler ise atıksu arıtımı uygulamalarındaki performansı açısından sentetik reçinelerin gerisinde kalsa da maliyet yönüyle dezavantajlarını telafi etmektedirler. Doğal iyon değiştirici zeolit minerallerinin kaynakları açısından oldukça zengin olan ülkemizde iyon değişim uygulamalarının yaygınlaşması ekonomi ve erişilebilirlik anlamında oldukça önemli avantajlar sağlayacaktır. Bu çalışma kapsamında iyon değişimi uygulamalarında en sık rastlanan zeolit türleri incelenmiş ve bu zeolit türlerine ait su ve atıksu arıtımı uygulamalarından örnekler verilmiştir.

Synthesis of 4A Zeolite and Characterization of Calcium- and Silver-Exchanged Forms

Calcium exchanged A type zeolite is extensively used as an adsorbent in petroleum and gas purification application. The precursor of calcium and silver-exchanged zeolite was prepared in a hydrothermal process, followed by an exchange process. In this study, LTA zeolite was synthesized. Calcium-ex- changed and silver-exchanged molecular sieves were prepared and characterized by a series of techniques, such as scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, etc. Physical properties of Ca- and Ag-exchanged zeolite A, such as surface structure, crystal structure, cation exchange capacity, and the ion-exchange properties were measured. Water adsorption studies using thermogravimetric method indicated that water molecules are more strongly bound in the Ca-A zeolite compared to Ag-A zeolite. XPS studies confirmed the presence of highly dispersed cationic silver species at exchange sites. The results of this study indicated that sodium was successfully exchanged with the calcium and silver in both Ca- and Ag-ex- changed zeolite frameworks. High cation exchange capacity, tailored aperture size, high porosity and specific surface area, as well as high thermal stability make cation-exchanged A type zeolite a successful candidate for adsorption, ion exchange, and catalysis applications.

Ion-Exchange Applications of Newly Synthesized of Aminoacetophenone, Biuret, Formaldehyde Derivative as New Chelating Terpolymer Resin

Ion-Exchange Applications of Newly Synthesized of Aminoacetophenone, Biuret, Formaldehyde Derivative as New Chelating Terpolymer Resin

Synthesis and Characterization of Ultrahigh Ion-Exchange Capacity Polymeric Membranes

A universal mold casting approach for the preparation of cation-exchange membranes (CEMs) and anion-exchange membranes (AEMs) with ultrahigh ion-exchange capacities (IECs) is developed based on in situ cross-linking polymerization of acrylic acid (AA) and 2-vinylpyridine (2VP), respectively. This new method produced ultrahigh IECs of 7.88 mequiv g–1 for CEM and 6.27 mequiv g–1 for AEM, which are 8.8 and 7.0 times that (0.89 mequiv g–1) of Nafion 117, respectively. Also, the prepared membranes demonstrate excellent thermal and chemical stability and acceptable conductivity. As a consequence, the membranes show relatively high performance for ion-exchange application and methanol barrier, exhibiting ion permeabilities of 2.06 × 10–7 cm2 s–1 for Na+, 2.57 × 10–7 cm2 s–1 for Ca2+, 1.45 × 10–7 cm2 s–1 for Cu2+ regarding CEMs, and 7.72 × 10–7 cm2 s–1 for methanol regarding AEMs. These results indicate that the CEMs and AEMs fabricated from the universal mold casting approach are promising candidates for targeti...

Impacts of main parameters on the regeneration process efficiency of several ion exchange resins after final purification of olive mill effluent

Abstract The key for the cost-efficient application of ion exchange (IE) processes relies on the fact that resins should be effectively regenerated to ensure their operation for the maximum possible working cycles. The main objective of this research work was to examine the effect of the main parameters affecting the regeneration process of several IE resins previously used for the purification of secondary-treated olive mill wastewater (OMW-2ST), comprising regenerant concentration and type, operating temperature and flow rate. For this purpose, the impacts on the regeneration and rinse times as well as the regeneration efficiency were addressed. Results show regeneration time decreased but rinse time increased with regenerant concentration increment for all resins. As a general rule, minor flow rate (2.5 L h −1 ) provided the highest possible regeneration, whereas efficiencies above 96% were noted upon the lowest temperature examined (298 K), which have both important implications on the cost-efficiency of the regeneration and integral effluent treatment process. Finally, 0.6 L HCl 4% and 0.8 L H 2 SO 4 2% solutions achieved complete regeneration of Dowex Marathon C and Dowex MAC 3 resins, whereas 0.7 L and 1 L NaOH 4% ensured complete regeneration of Amberlyst A26 and Amberlite IRA-67 resins, respectively.

Investigations of the Mechanical and Hydrothermal Stabilities of SBA-15 and Al-SBA-15 Mesoporous Materials

Periodic mesoporous materials possess high surface to volume ratio and nano-scale sized pores, making them potential candidates for heterogeneous catalysis, ion exchange, gas sensing and other applications. In this study, we use in situ small angle x-ray scattering (SAXS) and molecular dynamics (MD) simulations to investigate the mechanical and hydrothermal stability properties of periodic mesoporous SBA-15 silica and SBA-15 type aluminosilica (Al-SBA-15) to extreme conditions. The mesoporous SBA-15 silica and Al-SBA-15 aluminosilica possess amorphous frameworks and have similar pore size distribution (pore size ∼9-10 nm). The in situ SAXS measurements were made at the B1 beamline, at the Cornell High Energy Synchrotron Source (CHESS). The mesoporous SBA-15 silica and Al-SBA-15 aluminosilica specimens were loaded in a diamond anvil cell (DAC) for pressure measurements, and, separately, with water in the DAC for hydrothermal measurements to high P-T conditions (to 255 °C and ∼ 114 MPa). Analyses of the pressure-dependent SAXS data show that the mesoporous Al-SBA-15 aluminosilica is substantially more mechanically stable than the SBA-15 silica. Hydrothermal measurements show a small net swelling of the framework at elevated P-T conditions, due to dissolution of water into the pore walls. Under elevated P-T conditions, the Al-SBA-15 aluminosilica shows significantly greater hydrothermal stability than the SBA-15 silica. Our MD simulations show that the bulk modulus value of periodic mesoporous SBA-15 silica varies exponentially with percentage porosity. Molecular dynamics simulations are being made in order to better understand how the pore architecture and the chemical composition of the host structure govern the stability properties of the mesoporous materials.

A new three-dimensional zinc(II) coordination polymer involving 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole and benzene-1,4-dicarboxylate ligands.

Metal-organic frameworks (MOFs) based on multidentate N-heterocyclic ligands involving imidazole, triazole, tetrazole, benzimidazole, benzotriazole or pyridine present intriguing molecular topologies and have potential applications in ion exchange, magnetism, gas sorption and storage, catalysis, optics and biomedicine. The 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole (tmb) ligand has four potential N-atom donors and can act in monodentate, chelating, bridging and tridentate coordination modes in the construction of complexes, and can also act as both a hydrogen-bond donor and acceptor. In addition, the tmb ligand can adopt different coordination conformations, resulting in complexes with helical structures due to the presence of the flexible methylene spacer. A new three-dimensional coordination polymer, poly[[bis(μ2-benzene-1,4-dicarboxylato)-κ(4)O(1),O(1'):O(4),O(4');κ(2)O(1):O(4)-bis{μ2-2-[(1H-1,2,4-triazol-1-yl)methyl-κN(4)]-1H-benzimidazole-κN(3)}dizinc(II)] trihydrate], {[Zn(C8H4O4)(C10H9N5)]·1.5H2O}n, has been synthesized by the reaction of ZnCl2 with tmb and benzene-1,4-dicarboxylic acid (H2bdic) under solvothermal conditions. There are two crystallographically distinct bdic(2-) ligands [bdic(2-)(A) and bdic(2-)(B)] in the structure which adopt different coordination modes. The Zn(II) ions are bridged by tmb ligands, leading to one-dimensional helical chains with different handedness, and adjacent helices are linked by bdic(2-)(A) ligands, forming a two-dimensional network structure. The two-dimensional layers are further connected by bdic(2-)(B) ligands, resulting in a three-dimensional framework with the topological notation 6(6). The IR spectra and thermogravimetric curves are consistent with the results of the X-ray crystal structure analysis and the title polymer exhibits good fluorescence in the solid state at room temperature.

Hydrolytically Stable Nanoporous Thorium Mixed Phosphite and Pyrophosphate Framework Generated from Redox-Active Ionothermal Reactions.

The first thorium framework compound with mixed-valent phosphorus-based (phosphite and pyrophosphate) ligands, [BMMim]2[Th3(PO3)4(H2P2O7)3] (ThP-1), was synthesized by ionothermal reactions concurrent with the partial oxidation of phosphoric acid. The overall structural topology of ThP-1 highly resembles that of MOF-5, containing only one type of three-dimensional channels with a window size of 11.32 Å × 11.32 Å. ThP-1 has a free void volume of 50.8%, making it one of the most porous purely inorganic actinide-based framework materials. More importantly, ThP-1 is highly stable in aqueous solutions over an extremely wide pH range from 1 to 14 and thus may find potential applications in selective ion exchange and catalysis.

A Water-Stable Cationic Metal-Organic Framework as a Dual Adsorbent of Oxoanion Pollutants.

A three-dimensional water-stable cationic metal-organic framework (MOF) pillared by a neutral ligand and with Ni(II) metal nodes has been synthesized employing a rational design approach. Owing to the ordered arrangement of the uncoordinated tetrahedral sulfate (SO4 (2-) ) ions in the channels, the compound has been employed for aqueous-phase ion-exchange applications. The compound exhibits rapid and colorimetric aqueous-phase capture of environmentally toxic oxoanions (with similar geometries) in a selective manner. This system is the first example of a MOF-based system which absorbs both dichromate (Cr2 O7 (2-) ) and permanganate (MnO4 (-) ) ions, with the latter acting as a model for the radioactive contaminant pertechnetate (TcO4 (-) ).