Separation Factor Values Research Articles

Adsorption of Pb(II) ions from aqueous solutions using chemically treated and untreated cow dung ash

Batch experiments were conducted to evaluate the removal of Pb(II) ions from aqueous solutions using chemically and thermally activated cow dung (CTAC) ash and non-chemically but thermally activated cow dung (NTAC) ash under various experimental conditions. The optimum pH for the adsorption process using CTAC and NTAC was 5, while the optimum times using CTAC and NTAC were 240 and 180 min, respectively. Freundlich, Temkin, and Langmuir isotherm models were used to analyze the generated adsorption data. The Freundlich model had the highest coefficient of determination (R2) values that ranged from 0.989 to 0.999. The values of separation factor (RL) deduced from Langmuir isotherm were between 0 and 1 for both CTAC and NTAC ashes for the whole temperature range, which indicated favourable adsorption. Adsorption of the Pb(II) ions followed the pseudo-second-order kinetic model based on the R2 values that approached unity. Thermodynamic analyses revealed that the ΔH° values for CTAC and NTAC ashes were -8.69 and -11.39 kJ/mol, respectively, which indicated that ion adsorption was exothermic. Negative ∆S° values for the two adsorbents showed that the level of entropy was low at the solid/solvent interface during the adsorption process.

Observation of 18O/16O isotope effects at the cathode of a polymer electrolyte membrane fuel cell

ABSTRACT18O/16O isotope effects were observed at the cathode of a polymer electrolyte membrane fuel cell at 25 and 35°C. Results of experiments in which the 18O/16O isotope ratios of the oxygen gases supplied to and exhausted from the cell were measured revealed that the lighter isotope 16O reacted more preferentially to form water molecules at the cathode than the heavier one, 18O. The value of the oxygen isotope separation factor, S1, defined as the ratio of the 18O/16O isotope ratios of the oxygen gases supplied to and exhausted from the cell, ranged from 1.0030 to 1.0139, and tended to decrease with decreasing rate of oxygen utilisation (θ) and with increasing flow rate of the feed oxygen gas (DF). The value of another separation factor, S2, defined as the ratio of the 18O/16O isotope ratios of the exhausted oxygen gas and oxygen having reacted to form water molecules at the cathode, ranged from 1.0049 to 1.0304. The S2 value was much less affected by the change in θ and DF than the S1 value with the majority of the S2 value being in the range of 1.0240–1.0304.

Separation of hafnium from zirconium in hydrochloric acid solution with di(2-ethylhexyl)phosphoric acid by solvent extraction

The preparation of nuclear-grade zirconium and hafnium is very important for nuclear power. The separation of hafnium from zirconium in a hydrochloric acid solution by solvent extraction was investigated with di(2-ethylhexyl)phosphoric acid (D2EHPA). The effects of hydrochloric acid concentration, extractant concentration, diluents, and temperature on the distribution coefficient of hafnium and zirconium were studied. The species extracted were ZrOA2·2HA and HfOA2·2HA. In this process, the separation factors varied with different diluents and followed the order octane > hexane > toluene > chloroform. A high separation factor value of 4.16 was obtained under the conditions of a solution containing 0.05 mol/L HCl and 0.01 mol/L D2EHPA for the separation of hafnium from zirconium. The extraction reaction was endothermic.

Enhanced adsorption of nitrate from water by modified wheat straw: equilibrium, kinetic and thermodynamic studies.

This study represents the first attempt to chemically modify wheat straw (WS) using 3-chloropropyltrimethoxysilane (CPTMS) and (1,4-diazabicyclo[2.2.2]octane) (DABCO). Field emission scanning electron micrographs (FESEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectra confirmed the successful morphological and structural modification of WS and the thermal stability of the modified WS (MWS). The MWS was used to remove nitrate from water. The optimum conditions of nitrate adsorption onto MWS were examined by conducting batch experiments. The results indicated that 85% of nitrate was removed under the conditions of initial nitrate concentration = 20 mg L-1, initial solution pH = 7, contact time = 10 min, MWS dosage = 2 g L-1 and temperature ≈ 25 °C. The kinetic adsorption data were best fitted to the general order model and the adsorption process occurred in three distinct stages. The equilibrium adsorption data were well described by the Langmuir isotherm. Additionally, separation factor values were smaller than 1, implying that the adsorption process was favorable. The presence of competing anions impeded the nitrate adsorption in the order of sulfate > chloride > bicarbonate> phosphate. Thermodynamic parameters suggested that the adsorption process was exothermic, feasible and spontaneous in nature. Overall, the MWS could achieve efficient removal of nitrate under the simplest operating conditions.

Economic potential assessment of rare earth extraction sequence based on rule-based framework

Rare Earth Element (REE) is a unique group of metals which mainly comprises seventeen (17) elements, which fifteen (15) elements from the lanthanides group plus Scandium and Yttrium. This REE can be divided into heavy rare earth element (HREE) and light rare earth element (LREE) categories. During the initial extraction stage, the LREE is separated from HREE of the original ore and the sub-separations are then conducted subsequently corresponding to the respective categories. However, the separation difficulty becomes rather critical in a certain context, whenever the HREE is the major element to be extracted relative to LREE. In addition, there are no systematic guidelines procedures available to determine which specific separation pathway is more economically feasible among the various extraction options that exist. Thus, this study proposes a systematic quantitative rule-based framework, by excel modelling, in assessing comprehensively the economic potential of any separation model of REE processing that considered, whereby the standard characterization of monazite mineral composition is utilized as the main case study. This work also adopts the separation factor value of HDEHP-HCL as well as EHEHPA-HCL as the main extraction platforms. The findings suggest that the former extractant is effective for the extraction of light REE (LREE), while the latter incline to prefer the medium and heavy REE (MREE and HREE) particularly on the ground of separation stages factor. In light of the initial results, this study also proposes a hybrid approach in performing the complete optimal REE separation that specifically based on the sequence of ‘Art versus Science’ (AvsS) structure. These results have demonstrated that the proposed quantitative rule-based framework able to determine the optimal separation pathway provided the complete separation factor values and the mineral characterization of REE are available for assessment. Thus, this new method is suitably applied as a tool or guidelines in the feasibility study of any processing design for REE separation.

β-Factor Based Separation Characteristics of Bio-derived Chemicals Present in Lignocellulosic Hydrolysates Using Vacuum Distillation

A chief shortcoming in the bioconversion of lignocellulosic feedstock is the immanent formation of byproducts such as organic acids, furans, and phenols during the pretreatment process, and these byproducts restrict subsequent microbial fermentation and spent stream disposal. Thus, a green and alternative technique for simultaneous removal and recovery of inhibitors is indispensable. This study explored the separation characteristics of organic acids (acetic acid and formic acid), and furans (furfural and 5-hydroxymethylfurfural) present in simulated and crude lignocellulosic acid-hydrolysates using vacuum distillation. The operation parameters selected for distillation experiments were low temperature (333.15 K) and subatmospheric pressure (13.7 ± 1.3 KPa). A modified separation factor β was introduced in a microlevel model to specify the separation characteristics. Furfural had the highest separation factor (value = 1), whereas acetic acid and formic acid had separation factors in the ranges of 0.17 to ...

Chiral separation and modeling of quinolones on teicoplanin macrocyclic glycopeptide antibiotics CSP.

New chiral high-performance liquid chromatography (HPLC) method for the enantiomeric resolution of quinolones is developed and described. The column used was Chirobiotic T (150×4.6mm, 5.0μm). Three mobile phases used were MeOH:ACN:Water:TEA (70:10:20:0.1%), (60:30:10:0.1%), and (50:30:20:0.1%). The flow rate of the mobile phases was 1.0mL/min with UV detection at different wavelengths. The values of retention, resolution, and separation factors ranged from 1.5 to 6.0, 1.80 to 2.25, and 2.86 to 6.0, respectively. The limit of detection and quantification ranged from 4.0 to 12ng and 40 to 52ng, respectively. The modeling studies indicated strong interactions of R-enantiomers with teicoplanin chiral selector than S-enantiomers. The supra molecular mechanism of the chiral recognition was established by modeling and chromatographic studies. It was observed that hydrogen bondings and π-π interactions are the major forces for chiral separation. The present chiral HPLC method may be used for enantiomeric resolution of quinolones in any matrices.

First Report on the Complexation of Actinides and Lanthanides Using 2,2',2''-(((1,4,7-Triazonane-1,4,7-triyl)tris(2-oxoethane-2,1-diyl)) tris(oxy)) tris( N, N-dioctylacetamide): Synthesis, Extraction, Luminescence, EXAFS, and DFT Studies.

A novel tripodal diglycolamide ligand containing a triazamacrocycle center (2,2',2''-(((1,4,7-triazonane-1,4,7-triyl)tris(2-oxoethane-2,1-diyl)) tris(oxy)) tris( N, N-dioctylacetamide), abbreviated as T9C3ODGA) was synthesized and characterized by conventional techniques. The ligand resulted in efficient extraction of actinide/lanthanide ions yielding the trend: Eu3+ > Pu4+ > Am3+ > NpO22+ > UO22+ > Sr2+ > Cs+. Similar to most of the other diglycolamide (DGA) ligands, Eu3+ was preferentially extracted as compared to Am3+; the separation factor ( DEu/ DAm) value at 3 M HNO3 was ca. 4.2. In contrast, separation from UO22+ ion was less effective as compared to that of other tripodal DGA ligands studied earlier. Solvent extraction studies indicated extraction of species of the ML2 (where L is T9C3ODGA) stoichiometry. The formation of an inclusion complex with no inner-sphere water molecule was confirmed from luminescence spectral studies. DFT computations predicted the presence of an inner-sphere nitrate ion in the most preferred complex, which was also supplemented by EXAFS and luminescence studies. The selectivity of T9C3ODGA could be explained on the basis of its more favorable interactions with Eu3+ as compared to those with Am3+ both in the gas and the solution phases.

Separation of boron isotopes by chemical exchange in liquid-liquid systems

The currently used technologies for the production of boron isotopes for nuclear power and nuclear medicine are based on the application of toxic boron halides. The report is devoted to alternative processes for enrichment of 10B and 11B by chemical exchange in extraction systems using boric acid, that is, without of boron halides. The results of studying phase and isotope equilibrium in two liquid-liquid systems are considered: an aqueous solution of boric acid – an organic phase in the form of tributyl phosphate or a solution of trioctylamine in o-xylene. The obtained values of the separation factor for boron isotopes characterize the predominantly phase isotope effect in the first system, and in the second system the effect of chemical isotope exchange. Accordingly, the values of the single stage separation factor are 1.0067 ± 0.0035 and 1.025 ± 0.005 and are close to similar values for rectification of boron trifluoride and chemical exchange in the anisole process of boron isotope separation. The practical use of the studied extraction systems may allow the separation of boron isotopes in the horizontal cascades of centrifugal extractors in the absence of an environmental hazard.

The Surface Functionalization of Fe3O4 Nanoparticles by CTAB as Adsorbent for Methyl Orange Elimination in Water

Adsorption is the most extensively used technique for elimination of dye in contaminant water. Magnetically separation of toxic pollutant is becoming a potential method for water purification and obtained more effective and simple compared to conventional method of treatment. The surface-functionalized magnetic iron oxide nanoparticles with cetyl trimethyl ammonium bromide (CTAB-coated CTAB) has been investigated. CTAB-coated Fe3O4 were synthesized by precipitation of ferrous/ferric chloride (mole ratio 2:1) in CTAB/ammonium hydroxide solution mixture. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption isothermal and Fourier transforms infrared spectroscopy. The CTAB-coated Fe3O4 nanoparticles exhibited ability significantly to eliminate methyl orange in water compared to uncoated Fe3O4. Dye adsorption equilibrium state data were fitted well to the Langmuir isotherm were obtained the favorable of constant separation factor value (RL) (0.005-0.03). The CTAB coated Fe3O4 followed the pseudo-second-order kinetic model, resulting in the rate constant adsorption value for the elimination of methyl orange was 0.0694 g.mg-1.h-1. CTAB coated Fe3O4 nanoparticles have relatively high saturation magnetization, which allowed their highly-efficient magnetic separation from wastewater. This investigation was concluded than CTAB-coated Fe3O4 nanoparticles was efficient to eliminate dye from wastewater

Selective separation of Cu, Ni and Ag from printed circuit board waste using an environmentally safe technique

Printed circuit boards (PCBs) make up a large part of e-waste and include high concentrations of high-value metals. Therefore, the recovery of these metals is interesting from both the environmental and economic points of view. Here, the extraction/separation of copper, nickel and silver from PCB leachate was studied using an aqueous two-phase system (ATPS) formed by triblock copolymers with an electrolyte and water, which is in compliance with the principles of green chemistry. The best conditions for the selective extraction consisted of 1-(2-pyridylazo)-2-naphthol (3.5 mmol kg−1) at pH = 6.0 in 6 sequential steps for the Cu(II), dimethylglyoxime (5.00 mmol kg−1) at pH = 9.0 for the Ni(II) and thiocyanate (5.20 mmol kg−1) at pH = 9.0 for the Ag(I). These conditions were applied sequentially for extraction of Cu, Ni and Ag from the PCB leachate, obtaining high separation factor (S) values between the analyte and the metallic concomitants (SCu,Ni = 1,460, SCu,Fe = 15,500, SCu,Ag = 15,900, SNi,Fe = 32,700, SNi,Ag = 34,700 and SAg,Fe = 4800). The maximum extraction percentages (%E) for Cu, Ni and Ag were 99.9%, 99.9% and 99.8%, respectively. After the extraction, a single step stripping process was performed, resulting in more than 82% of the ion available in a clean lower phase. For the first time, an ATPS has been used for sequential extraction of several metal analytes from a real sample.

Two-step preparation of amidoxime-functionalized natural zeolites hybrids for the removal of Pb2+ ions in aqueous environment

Amidoxime-functionalized natural zeolites hybrids were prepared through two-step method including γ-irradiation for the grafting polymerization of polyacrylonitrile (PAN) and chemical transformations of nitrile groups (–R–C≡N) to amidoxime groups (–R–C(NH2) = NOH). This study aims to combine the good mechanical properties of low-cost inorganic matrices, i.e. natural zeolites, with strong chelating ability, which is potential for adsorbing toxic metal cations, especially Pb2+. The grafting polymerization of PAN depended on the γ-irradiation dose and dose rate. The optimized condition for the highest degree of grafting (20%) and maintained zeolites structure lies at the irradiation dose of 100 kGy at a dose rate of 2 kGy h−1. It was indicated that the grafting polymerization of PAN also occurred inside the micropores since the micropore volumes cannot be detected by N2 adsorption-desorption isotherms after grafting polymerization and chemical transformations. Moreover, the grafted PAN probably formed a chemical bonding with the zeolites since they exhibited the peaks of ≡Si–O and ≡Si sites in the ESR spectra of zeolites after γ-irradiation. The amidoxime-functionalization was confirmed by FTIR spectroscopy which showed the transformation of C≡N band into C=N, C–N and N–OH bands and SEM-EDX which exhibited the morphology alteration and the enhancement of C and N atoms percentage. The two-step preparation appeared to not alter the structure of zeolites as shown by XRD and 27Al MAS NMR spectroscopy. The amidoxime-functionalized natural zeolites hybrids exhibited maximum adsorption capacity of 72 mg g−1 towards Pb2+ in the aqueous environment which was comparable and, even, higher than several previous reports. The adsorption process followed the Langmuir model with favorable adsorption based on the separation factor values, while the adsorption kinetics are based on pseudo-second order model.

Similarly sized protein separation of charge‐selective ethylene‐vinyl alcohol copolymer membrane by grafting dimethylaminoethyl methacrylate

ABSTRACTSimilarly sized protein separation was investigated using a charge‐selective membrane, which prepared by grafting dimethylaminoethyl methacrylate (DMAEMA) onto ethylene vinyl alcohol copolymer (EVAL) membrane. Bovine serum albumin (BSA) and bovine hemoglobin (BHb) was used as model proteins. P(DMAEMA), the weak cationic polyelectrolyte with ionizable tertiary amine groups, contributed to the charge‐selective separation for BSA and BHb. At pH 6.0, the grafted EVAL membrane surface was positively charged and BSA was negatively charged, while BHb was positively charged. The BSA was adsorbed onto the membrane surface due to electrostatic interaction and the BHb passed through the membrane into the permeate. The charge‐selective behavior resulted in the separation of the similarly sized protein. The maximum separation factors of static adsorption separation for model protein and binary mixture were 32.4 and 37.2, respectively. In the dynamic separation process, the maximum separation factor value was 6.2. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46374.

Decolourization of malachite green dye by mentha plant biochar (MPB): a combined action of adsorption and electrochemical reduction processes

Adsorption behavior of mentha (mint) plant biochar (MPB) in removal of malachite green (MG) dye from aqueous solution was analyzed as a function of different pH (4.0-10.0), initial dye concentration (20-100 mg/L), contact time (0-45 min) and dose of adsorbent (0.05-0.3 g/100 mL). The zeta potential of the MPB particles was found to be -37.9 mV, indicating a negatively charged sorption surface of MPB particles. MPB was found to be more effective in removal of MG dye at pH 6.0 due to combined action of physico-chemisorption and a reductive electron transfer reaction. Results on the Brunauer-Emmett-Teller (BET) analysis of the N2 adsorption-desorption isotherm of MPB as adsorbent showed sigmoidal shape similar to the type IV isotherm and mesoporous nature. The cyclic voltammetric analysis of MG dye showed a reversible, coupled redox reaction at the interface of dye molecules and MPB particles. The maximum monolayer adsorption capacity (qmax) of MPB was found to be 322.58 mg g-1. The separation factor (RL) value was between 0 and 1, indicating a favourable adsorption of MG dye onto MPB. The results fitted well to a pseudo-second-order kinetic model. Further results from desorption experiments showed recovery of MG dye by about 50% in the presence of 1 N HCl.

Removal of Congo Red dye from aqueous solution using Amberlite IRA-400 in batch and fixed bed reactors

ABSTRACTRemoval of Congo Red (CR) azo dye by adsorption process using Amberlite IRA-400 resin was evaluated in both batch and fixed bed system. From the batch adsorption results, maximum loading efficiency (99.99%) of CR dye was obtained at the conditions pH 4.5, temp. 303 K, contact time 180 min., Amberlite IRA-400 dose 0.5 g. The isotherm study ascertained on favorability of adsorption process as the value of separation factor (KL = 0.88) and Freundlich constant (1/n = 0.96 < 1.0) obtained from Langmuir and Freundlich equations are rational, though, overall adsorption process showed best fit with Langmuir (R2 = 0.99) than Freundlich model (R2 = 0.97). The kinetic data studied at three different CR dye concentration (50, 75, 100 mg) and results were fitted with both pseudo-first-order and second-order model equations. The values of R2 obtained are of 0.95 and 0.99 for former and later one, respectively, ensuring on best fitting of pseudo-second-order kinetics and also suggesting about the chemisorptions type of adsorption. The bed depth service model was applied for competitive analysis of the CR dye adsorption in column variables indicating mass transfer from aqueous solution to Amberlite IRA-400 phase. Fourier transform infrared analysis of CR-loaded resin Amberlite IRA-400 showed a band shifted from 1057 to 1130 cm−1 confirming CR adsorption with Amberlite IRA-400. Scanning electron microscope analysis of resin before and after adsorption was well evident from the phase patterns. Selective separation of CR dye from waste effluent of a textile industry bearing CR dye along with other trace heavy metal was achieved.

Determination of carotenoids in two algae species from the saline water of Kapulukaya reservoir by HPLC

ABSTRACTThe local algae species, Chlorella vulgaris and Scenedesmus regularis, from a highly saline water body of Kapulukaya Reservoir were isolated to analyze their carotenoid composition and content using HPLC method. The gradient solvent system of methanol–acetonitrile–water (84:14:2, v/v/v) and methylene chloride (100%), used to resolve a range of carotenoids from the saponified cells, proved an acceptable separation as inferred from the retention factor (k) ranging between 0.75 and 7.76 and the separation factor (α) values greater than 1. Resolution peaks assigned to carotenoids, 21 for C. vulgaris extracts and 22 for S. regularis extracts, were reached within the duration time of 45 min. Main carotenoids identified either tentatively or positively were all-trans-lutein, 9- or 9′-cis-lutein, 13- or 13′-cis-lutein, cis-lutein, All-trans-α-carotene, 9- or 9′-cis-α-carotene, All-trans-β-carotene, 9- or 9′-cis-β-carotene in the species except for all-trans-β-cryptoxanthin found only in S. regularis. Auroxanthin, neochrome, neoxanthin, and cis-neoxanthin were identified as epoxy-containing compounds. Quantitatively, C. vulgaris was distinguished to have greater amount of lutein and cis-isomers (2.74 mg/g), 77.89% while S. regularis was predominated by β-carotene and cis isomers as major component, being 80.72% (5.76 mg/g) in total carotenoids (TC). In terms of total carotenoids, the species were considered to be efficient sources for further practical applications.

A diglycolamide-functionalized TREN-based dendrimer with a 'crab-like' grip for the complexation of actinides and lanthanides.

A generation 1 dendrimer, based on tris(2-aminoethyl)amine (TREN), containing six diglycolamide (DGA) pendent arms (termed TREN-G1-DGA) was synthesized and evaluated for the extraction of actinides and fission product ions. Solvent extraction studies indicated preferential extraction of Eu3+ over Am3+ with a separation factor value of ca. 4.5 in line with the extraction behaviour of multiple DGA ligands in previous reports. The distribution values of Am3+ and Eu3+ were about 12 and 9 times higher, respectively, than those obtained in the case of TREN-DGA using the 1 × 10-3 M ligand in 5% iso-decanol/95% n-dodecane at 3 M HNO3. The 1 : 1 (M : L) extracted species suggested 'inclusion' complex formation where more than one DGA moiety participates in the complex formation. The extracted species were devoid of any inner-sphere coordinated water molecules as confirmed by luminescence spectroscopy. The structure of the complex was also studied by DFT computations and EXAFS which suggested binding of three DGA arms around the central metal ion in the absence of any inner-sphere nitrate ions.

Surface functionalized biomass for adsorption and recovery of gold from electronic scrap and refinery wastewater

Abstract In this study, polyethylenimine (PEI) modified Lagerstroemia speciosa leaves powder (PEI-LS) as low-cost and eco-friendly biosorbent was efficiently applied for gold recovery from acidic solution. Our experimental data show that PEI-LS is effective in complete recovery of gold at pH 1, compared to the raw L. speciosa leaves powder (raw LS) biomass. The adsorption kinetic results show gold adsorption reaches equilibrium in 6 h and follows a pseudo-second order kinetic. The adsorption isotherm data were best explained by Freundlich model and the monolayer adsorption capacity of PEI-LS for gold are in the range 286–313 mg/g. Thermodynamic parameters suggest that gold adsorption on PEI-LS was spontaneous and endothermic in nature. The developed PEI-LS was reusable up to 4 cycles with ∼98% gold recovery. Further, the calculated separation factor values suggest the PEI-LS shows high selectivity for low concentration of gold over the other co-existing metal ions in binary mixtures. Various instrumental characterization of raw LS and PEI-LS confirms the successful grafting of PEI on biomass surface. Surface analytical techniques like X-ray photoelectron spectroscopic (XPS) analysis confirms the adsorption-reduction mechanism of gold ions on PEI-LS leading to the formation of zero-valent gold on the biosorbent surface. The XPS was also used to characterize the PEI-LS surface functional groups (N1s) responsible for gold adsorption-reduction mechanism. The PEI-LS was successfully applied for quantitative gold recovery (≥95%) from an acidic solution of electronic scrap, gold refining sludge and wastewater.

Liquid–Liquid Equilibrium Data, Density, Viscosity, and Interfacial Tension of Ternary System (Toluene–Acetic Acid–Water) at 298.15 K: Experiment and Correlation

Liquid–liquid equilibrium (LLE) data, density, viscosity, and interfacial tension for the ternary system of toluene–acetic acid–water were measured at 298.15 K and 101.7 kPa. The Othmer–Tobias and the Hand correlations were used to check the reliability of the experimental tie-lines. Moreover, the distribution coefficient and the separation factor were explored. It was found from the experimental results that a maximum separation factor value happens at an acetic acid mass fraction of 0.02 in the organic phase. Density, viscosity, and interfacial tension were correlated using the appropriate correlations such that the predicted results have excellent agreement with the experimental data. The experimental data in this work and the literature were correlated using both the nonrandom two-liquid (NRTL) and the universal quasi chemical (UNIQUAC) activity coefficient models at various temperatures (288.2, 298.15, 303.15, and 313.15 K). The experimental results were used to obtain binary interaction parameters in these models. The root-mean-square deviation (RMSD) values for both models were less than 3.58%, and the model predictions show acceptable agreement with the measured data particularly at the plait point.

High performance anion exchange membrane with proton transport pathways for diffusion dialysis

Abstract High performance anion exchange membranes (AEM) with proton transport pathways were fabricated through cationic functionalization of bromo-methylated poly (phenylene oxide) (BPPO) by a nucleophile dimethylamino pyridine (DMAP). The reaction was selectively occurred at dimethylamino functionalities of DMAP to form quaternary amine groups. The pyridine groups on DMAP having a dibasic nature promoted the formation of proton transport pathways and contributed to hydrophilicity of the membranes. The obtained membranes had the water uptake (WU) in the range of 12–57%, the ion exchange capacity (IEC) from 0.84 to 2.07 mmol g−1, acid dialysis coefficient (UH) from 0.37 to 20.3 (10−3 m h−1) at 25 °C. Interestingly, these membranes exhibited superior separation factor (S) values of 73–351 compared to a commercial DF-120 membrane and most reported membranes in literature. Moreover, the prepared membranes showed excellent thermal, chemical and mechanical stability.