Separation Factor Values Research Articles

A novel Al-based MOF with straight channel and pocket pore structure for trace benzene adsorption and benzene/cyclohexane separation

Benzene (Bz) vapor poses significant health risks to humans, even at trace concentrations. Additionally, the separation and recycling of Bz and cyclohexane (Cy) is challenging due to their similar kinetic diameters and boiling points. Developing an adsorption-separation material with stronger interactions with Bz than with Cy could serve as a viable strategy for trace Bz adsorption and Bz/Cy separation. In this study, we present a novel aluminum-based metal–organic framework, ZJU-521(Al), composed of tetrakis (4-carboxyphenyl)methane and a helical chain [Al5(OH)7(−COO)8]∞, featuring a simple network of one-way rods and tetrahedra. This framework exhibited a uniform micropore size of 7.23 Å and a specific surface area of 1,248 m2 g−1, demonstrating excellent trace Bz adsorption (4.18 mmol g−1) at P/P0 = 0.01, attributed to its straight channel and orthogonal-array pocket pore structure. The ideal adsorbed solution theory selectivity and separation factor values of ZJU-521(Al) for Bz/Cy were 22.50 and 6.20, respectively, indicating its potential as a material for Bz/Cy separation. Multicomponent simulations showed that Bz molecules were preferentially adsorbed in the pocket due to stronger interactions, such as Al–π interactions. Thus, ZJU-521(Al) exhibits stronger interactions with Bz than with Cy, facilitating effective Bz/Cy separation.

Separating Neroli from Water Using the PDMS‐ZSM5 Mixed Matrix Membrane and the Pervaporation Method

AbstractIn this study, the separation of neroli from water by PDMS‐ZSM5 mixed matrix membrane and separation performance of the pervaporative process of the prepared membranes with the parameters of permeability flux and separation factor was investigated. The effect of adding nanoparticles in the polymer matrix, the effect of the operating parameter of temperature and concentration on the efficiency of the membrane in the pervaporative process to be placed. Comparison of the results for pure membrane and mixed matrix membrane shows a 3‐fold increase in flux along with a 5‐fold increase in the separation factor in the mixed matrix membrane with a ratio of 12% nano in the membrane matrix so that the permeability and separation factor are 1.256 kg/m2h and 550, respectively. Membrane function was also evaluated in the temperature range of 298–353 K and feed concentration of 122–209 ppm. With increasing temperature to 353 K, permeability of membrane containing 8% ZSM‐5 nanoparticles increased from 0.63 to 0.89 kg/m2h. Also, with increasing feed concentration, permeability increased from to 0.96 kg/m2h. The optimization of these conditions was investigated by response surface method (RSM) based on the design of central points (CCD). The effect of all three parameters on the permeability, flux, and separation factor was investigated simultaneously and the optimal conditions were obtained at 12 wt% of ZSM‐5, a concentration of 209 mg/L of neroli, and a temperature of 304 K. Under these optimal conditions, the values of permeability, flux, and separation factor were 1.414 kg/m2h and 1039.57, respectively.

Performance assessment and characterization of the biosorption of the azo dye reactive Red 2 on thermally inactivated biomass of Trichoderma reesei

The present study evaluated and characterized the performance in the biosorption of the dye azo Reactive Red 2 (RR2) on thermally sterilized biomass of the fungus Trichoderma reesei. An FTIR analysis of unloaded and loaded biomass with RR2 confirmed the interactions between dye molecules and functional groups on the fungal biomass surface. The decrease in the initial pH of 9 to 3 with an increase in the temperature of 20 to 40 °C improved the biosorption, reaching for RR2 a higher removal efficiency of 76.88% at pH 3 and 40 °C. A pseudo-second-order model explained the biosorption kinetics of RR2 (R2≥0.9869), and the intraparticle diffusion model showed that the biosorption process was initially controlled by diffusion rate and later by biomass surface saturation with the dye molecules. The Langmuir isotherm explained the biosorption equilibrium well (R2 ≥ 0.9241), achieving the maximum biomass biosorption capacity (qmax ) value at 61.72 mg g−1. The dimensionless separation factor values (0.0632 ≤ RL ≤ 0.0973) and the thermodynamic evaluation of the process (ΔG° ≤ −24.09 kJ mol−1, ΔH° ≥ 12.39 kJ mol−1, ΔS° ≥ 0.1265 kJ mol−1 K−1) demonstrate that the biosorption was favorable, reversible, spontaneous, and endothermic. The findings in the present study allow it to consider the biomass of Trichoderma reesei thermally sterilized as a biosorbent biomaterial that can be used for bioprocess design in removing the azo reactive dyes from textile wastewater.

Separation of Nd(III) from Nd(III)/Co(II) Mixture Using Poly (Carboxymethyl Cellulose.starch-g-acrylic Acid/Al2O3) Nanocomposite

AbstractThe separation of neodymium from the Nd(III)/Co(II) mixture is crucial for producing high-purity neodymium, which is essential in industries like electronics. A new nanocomposite, Poly(carboxymethyl cellulose.starch-g-acrylic acid/Al2O3), P(CMC-St-g-AA/Al2O3), was prepared and applied for the sorption and separation of Nd(III) from the Nd(III)/Co(II) mixture. This nanocomposite, synthesized with γ-irradiation of 60Co at 35 kGy, was extensively characterized using SEM, FTIR spectroscopy, and TGA-DTA. Parameters affecting neodymium separation were studied, revealing optimal conditions. Kinetic experiments showed agreement with a pseudo-nth-order kinetic model. Isothermal sorption studies indicated multilayer adsorption, with Co(II) and Nd(III) adsorption capacities of 2.781 mg/g and 8.825 mg/g, respectively, at pH 3.0. Thermodynamic analysis confirmed spontaneous and endothermic sorption. Separation factor values peaked at pH 3.0, shaking for 120 min, 0.1 adsorbent dosage, and ambient temperature, highlighting effective Nd-Co separation under these conditions. In conclusion, the comprehensive analysis and successful application of P(CMC-St-g-AA/Al2O3) nanocomposite underscore its potential as a highly efficient and selective sorbent for neodymium separation.

Solvent extraction of La, Nd, and Eu using a newly designed solutions spray system

This research covers a new continuous solvent extraction “solutions spray system” technique to extract lanthanum (La), neodymium (Nd), and europium (Eu) from chloride solution using DEHPA. This setup enhanced the extraction kinetics and mass transfer compared to the conventional mixer-settler by generating micro-sized droplets of the feed streams in the mixing chamber, causing speedy and better mass transfer, and the special design of the settling column boosted the separation process with improved quality products. Variables like pH, DEHPA concentration, ionic strength, and aqueous/organic phase ratio were studied to determine the performance of this setup. At the optimum values of these variables (2.0 pH, 0.303 M DEHPA, and 1.54 mol/L ionic strength), the percent extraction of La, Nd, and Eu was 95.03 %, 99.36 %, and 99.98 %, and the distribution ratio was 19.14, 155.25 and 4165 respectively, which showed the extraction in a single stage. Furthermore, the values of separation factors, SFEu/La = 6.69, SFEu/Nd = 5.33, and SFNd/La = 1.26 at 0.50 pH, showed the selectivity of these elements. Later on, McCabe Thiele diagrams were plotted for extraction and stripping sections to see the minimum number of theoretical stages for the complete recovery of REEs and their selective separation from each other.

Silica-Reinforced AMP-Calcium Alginate Beads for Efficient and Selective Removal of Cesium from a Strong Acidic Medium.

Due to the significant selectivity for Cs+, ammonium molybdophosphate (AMP) possesses potential to uptake radiocesium from high-level liquid waste (HLLW), whereas its micro-crystalline structure and fine powder morphology limit its industrial application. Although the granulation method with alginate is prospective for the preparation of an AMP exchanger, the mechanical strength of obtained beads may be insufficient for application. In this context, we prepared silica-reinforced AMP-calcium alginate (ACS) beads and evaluated their performance for Cs+ removal from strong acidic solutions. It was found that the addition of silica in the fabrication significantly improved the mechanical strength of the beads in comparison to those without silica. Notably, the beads with an AMP/silica mass ratio of 1.0 exhibited an exceptional mechanical strength, surpassing that of ACS beads composed of other components. The batch experiment results indicated that the Cs+ adsorption follows a non-linear pseudo-second-order rate equation. The distribution coefficient of Cs+ was high even in extreme acidic conditions (∼1.6 × 102 mL/g in 8.0 mol/L HNO3 solution). The Cs+ adsorption can be well fitted with the Langmuir model, and the estimated maximum exchange capacity in 3.0 mol/L HNO3 could reach 23.9 mg/g. More importantly, ACS beads showed excellent selectivity toward Cs+ uptake over eight co-existing metal ions in simulated HLLW, with separation factor values all above 145. The column experiment exhibited that the beads can serve as the stationary phase in columns to effectively remove Cs+. The findings of this study are significant as they provide insights into the development of efficient materials for radiocesium removal from high-level liquid waste. The results demonstrate the potential of silica-reinforced ACS beads for Cs+ adsorption, with promising applications in industrial settings.

Remarkable Improvement in Am3+ and Cm3+ Separation Using a Cooperative Counter Selectivity Strategy by a Combination of Branched Diglycolamides and Hydrophilic Polyaza-heterocycles.

Separation of Am3+ and Cm3+ is one of the most challenging problems in the back-end of the nuclear fuel cycle. In the present work, we exploited the cooperative effect of the opposite selectivity of hydrophobic branched DGA derivatives and hydrophobic N-donor heterocyclic ligands taken in two different phases to achieve improved separation behavior. A systematic study was performed using a series of DGA derivatives to understand the effect and the position of branching in the alkyl chains on the separation behavior of Am3+ and Cm3+. A separation factor (S.F.) value as high as 10 for Cm3+ over Am3+ was obtained in the case of TiBDGA (N,N,N',N'-tetra-iso-butyl diglycolamide) using SO3PhBTPhen ((phenanthroline-2,9-diyl)-1,2,4-triazine-5,5,6,6-tetrayltetrabenzenesulfonic acid) as the aqueous complexant, which is the highest reported value so far for the ligand-based separation of Am3+ and Cm3+ without involving any oxidation or reduction step. The high selectivity favoring Cm3+ ion extraction in the case of this DGA derivative is also explained with the help of computational studies.

Adsorption isotherm, kinetic and thermodynamic studies for adsorption of fluoride on waste marble powder

Economically viable, efficient waste marble powder (WMP) for fluoride removal has been studied. A batch adsorption study has been carried out concerning contact time, initial concentration, adsorbent dosage, pH, and temperature. After using a batch adsorption mode, 97.13 % removal efficiency was observed with an adsorption capacity of 1.166 mg/g at the initial fluoride concentration of 6 mg/L, solution pH of 6, adsorbent dosage of 500 mg, temperature of 35 °C, and contact time of 60 min. According to kinetics studies, the experimental adsorption data fit well in a nonlinear pseudo-second order with the adjusted-R2 value 0.999, and the nonlinear Langmuir isotherm model fitted best with the adjusted-R2 value 0.988. The separation factor (RL) values were within the range of 0.178 - 0.086, suggesting a satisfactory uptake of fluoride ions. Thermodynamic analysis showed that the adsorption process was endothermic, and negative values of Gibbs free energy change (∆Go) indicated spontaneous fluoride adsorption. In contrast, a positive value of entropy change (∆So= 65.26) indicated arbitrary behaviour at the interface between the solid and the solution. Fluoride removal from aqueous solution was also studied using a continuous fixed-bed column. The Yoon-Nelson model, with a higher adjusted-R2 value of 0.9906, described the dynamics of the fluoride adsorption process better than the Adams-Bohart model because it had better predictions for the breakthrough curve. According to the regeneration analysis, 52 % of the adsorption rate with an adsorption capacity of 0.604 mg/g could be achieved even after five cycles of WMP regeneration.

A simple method to prepare anion exchange membrane by PVA/EVOH/MIDA for acid recovery by diffusion dialysis.

Given the substantial environmental pollution from industrial expansion, environmental protection has become particularly important. Nowadays, anion exchange membranes (AEMs) are widely used in wastewater treatment. With the use of polyvinyl alcohol (PVA), ethylene-vinyl alcohol (EVOH) copolymer, and methyl iminodiacetic acid (MIDA), a series of cross-linked AEMs were successfully prepared using the solvent casting technique, and the network structure was formed in the membranes due to the cross-linking reaction between PVA/EVOH and MIDA. Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to analyze the prepared membranes. At the same time, its comprehensive properties which include water uptake, linear expansion rate, ion exchange capacity, thermal stability, chemical stability, and mechanical stability were thoroughly researched. In addition, diffusion dialysis performance in practical applications was also studied in detail. The acid dialysis coefficient (UH+) ranged from 10.2 to 35.6 × 10-3 m/h. Separation factor (S) value ranged from 25 to 38, which were all larger than that of the commercial membrane DF-120 (UH+: 8.5 × 10-3 m/h, S: 18.5). The prepared membranes had potential application value in acid recovery.

Chiral separation of terbutaline by supercritical fluid chromatography with peak purity determination by UPLC–MS and modeling for chiral recognition mechanism

AbstractBACKGROUNDTerbutaline is the drug of choice for asthma patients but it exists in racemic mixture. (R)‐(−)‐terbutaline is 200 times more active than (S)‐(+)‐terbutaline yet it is not advisable to prescribe racemic mixture due to certain adverse effects of (S)‐(+)‐terbutaline. Therefore, a fast, effective and reproducible separation method is necessary.RESULTSChiral separation was achieved on Chiralpak‐IE and Chiralpak‐IG columns (250 × 4.6 mm, 5 μm) using carbon dioxide‐methanol (CO2‐MeOH, 60:40) with a 0.2% triethylamine mobile phase. The flow was 1.0 mL min−1 with detection at 223 nm using a photodiode array (PDA) detector. The values of retention, separation and resolution factors were in the ranges 1.88–2.38, 1.14–1.26 and 0.91–1.17, respectively; with best separation with Chiralpak‐IE. The tailing factors and number of theoretical plates were in the range of 1.0–1.23 and 487–3699. The purity of the separated peaks was determined by ultra‐performance liquid chromatography–mass spectrometry (UPLC–MS); indicating 100% purity of the peaks. The chiral recognition was determined by modeling with binding affinities −5.0 and −6.0 for S‐ and R‐enantiomers, respectively; indicating S‐enantiomer elution first followed by R‐enantiomers. The major forces responsible for the chiral resolution were hydrogen bonding and π‐π interactions.CONCLUSIONOwing to the great demand for optically active pure drugs and high economic pressure on analytical techniques, the chiral separation of terbutaline was achieved via inexpensive supercritical fluid chromatography. The reported method may be used to prepare optically active pure terbutaline drugs (R‐enantiomers) at a pilot scale. © 2024 Society of Chemical Industry (SCI).

Extraction of Rare Earth Elements from Chloride Solutions Using Mixtures of P507 and Cyanex 272

In this study, the extraction of rare earth elements (REEs) from chloride solutions after leaching REE carbonate concentrate with solutions of the mixtures of P507 (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) and Cyanex 272 (bis(2,4,4-trimethylpentyl)phosphinic acid) (1:1) at various concentrations was experimentally studied. It was shown that the distribution ratios of all REEs decrease with the increasing concentration of these metals in the initial solution, which is associated with the loading of the organic phase. The most significant improvement in the extraction is observed for the heavy group of rare earth elements. The extractability of REEs increases with the increasing atomic number of the element, as is typical for the extraction of these metals with acidic organophosphorus extractants. The data obtained show that the separation factors of adjacent rare earth elements decrease slightly with the increasing concentration of metals in the initial aqueous solution. Increasing the concentration of the extractant mixture does not have a significant effect on the values of the adjacent REE separation factors. The data obtained on the distribution ratios and separation factors made it possible to propose a flow sheet for the separation of rare earth elements with the production of Y, Ho, Tb and Dy.

Towards sustainable water purification: MOFs as a promising solution to eliminate toxic water pollutant resorcinol

Abstract Water pollutants especially alcoholic based aromatic compounds are documented as emergent water pollutants and caused serious health problems for all living organisms. It is a major challenge for all researchers to synthesize effective adsorbents to eliminate these water pollutants. For this purpose, two MOFs were synthesized and characterized using SEM, FTIR, EDX and PXRD techniques. These MOFs exhibited excellent adsorption capacity for resorcinol and adsorption process was spontaneous, endothermic and proceeds with physiosorption as confirmed using thermodynamics data (∆H ads = 30.473 kJ/mol). Furthermore, separation-factor value was in the range of 0.0238–0.1312 for 30–100 ppm resorcinol concentration which represents that adsorption process was favorable. Langmuir and Pseudo 2nd order Models were best described which represented that chemisorption process also favored due to presence of –OH group and N-atom between adsorbent and adsorbate as well as monolayer adsorption-process is proceeded. Moreover, ion-exchange and electrostatic-interactions are the major interactions which are responsible for adsorption of resorcinol. Along with electrostatic-interactions, ion-exchange, hydrogen-bonding and π–π stacking/interactions are also accountable for adsorptive elimination of resorcinol. In summary we can conclude that MOFs are considered outstanding adsorbents for elimination of water pollutants to purify water, as water is very important for healthy life.

Facile extraction of berberine from different plants, separation, and identification by thin-layer chromatography, high-performance liquid chromatography, and biological evaluation against Leishmaniosis.

The extraction of berberine was carried out from Berberis vulgaris, Berberis aquifolium, and Hydrastis canadensis plants using ethanol and water (70:30, v/v). The extracted berberine was characterized by ultraviolet-visible and Fourier-transform infrared spectroscopy. The purity of berberine was ascertained by thin-layer chromatography using n-propanol-formic acid-water (95:1:4) and (90:1:9) solvents. hRf values were in the range of 44-49 with compact spots (diameter 0.2-0.4cm). HPLC was carried out using ammonium acetate buffer and acetonitrile in gradient mode with Zodiac (4.6×150mm, 3μm) column. The flow rate was 1.0mL/min and detection was at 220nm. The values of separation and resolution factors of the standard and the extracted berberine were in the range of 1.13-1.16 and 1.40-1.71, respectively. A comparison has shown that both thin-layer chromatography and high-performance liquid chromatography (HPLC) methods found applications in different situations and requirements. The extracted berberine samples were used to treat Leishmaniosis and the results showed better activity of berberine in comparison to the standard drug Amphotericin B. Briefly, the reported research is a novel and may be used to extract berberine from plants, separation and identification of berberine by thin layer chromatography and HPLC and to treat Leishmaniosis.

Liquid-liquid equilibria of ternary mixtures containing Aniline + Toluene + water at elevated temperatures: measurements and correlation

ABSTRACT Liquid-liquid equilibrium (LLE) data for the ternary system, Aniline + Toluene + Water, was measured at different temperatures of 298.15 K, 313.15 K and 323.15 K under atmospheric pressure with the help of High-Performance Liquid Chromatography (HPLC) analysis and Karl-Fischer technique. The efficiency of Toluene to extract Aniline from aqueous phase was then quantified in terms of the distribution coefficient and separation factor based on the tie line data. The system showed very good separation ability quantified in terms of high values of distribution factor (average around 7) and separation factors (as high as 1000). The experimental tie line data was verified by Hand and Othmer-Tobias equations. The LLE data was also correlated using NRTL and UNIQUAC models and both of them were able to represent the behavior of the system accurately when tested against experimental results. Toluene has been demonstrated to be very efficient to extract Aniline from reaction mixture, which is typically a by-product in hydrogenation of nitrobenzene, a process commercially used to produce p-Aminophenol in industry.

Hydrophilic imprinted MnO2 nanowires “coating” membrane with ultrahigh adsorption capacity for highly selective separation of Artemisinin/Artemether

The selective separation and purification of ART and ARE using molecularly imprinted membrane (MIM) has attracted considerable attention, but most of conventional blending MIM face low adsorption capacity and poor selectivity due to the blockage of imprinting sites. Herein, an alternative ART imprinted MnO2 nanowires “coating” membrane (MINM) withhydrophilicity was fabricated by vacuum filtration of imprinted MnO2 nanowires and graphene oxide nanosheets on PVDF membrane surface for selective ART separation. For the MINM, the imprinted MnO2 nanowires coating offers more available exposed imprinting sites on the MINM surface compared to that of the blending MIM, while the introduction of graphene oxide improves the hydrophilicity of MINM, significantly reducing the non-specific absorption. Consequently, the MINM exhibits ultrahigh ART adsorption capacity and selectivity, with the ART adsorption amount of 335 mg g−1 at 5 min using dynamic cross-flow separation system, about 12.18 times higher than that of ARE (27.5 mg g−1), and the separation factor (a) value of 12.39. Moreover, the ATR FT-IR dynamic spectrum discloses the in-situ formation of H-bond between ART and MINM, playing a key role in the selective adsorption process. This work provides an alternative strategy to prepare “coating” MIM for high-efficient and selective separation of complex analogue systems.

Comparative Evaluation of Liquid–Liquid Phase Equilibria for Aqueous Mixtures of Acetic Acid with Structurally Related Aryl Carbonyl Compounds at 298.2 and 308.2 K

Experimental solubility curves and tie-line compositions were comparatively investigated for the aqueous mixtures of acetic acid with three structurally similar aryl carbonyl compounds (propiophenone, acetophenone, and methyl benzoate) at (298.2 and 308.2) K and 101 kPa. The studied ternary mixtures display type-1 phase behavior. The correlation of the measured tie lines was performed by the NRTL and UNIQUAC models. The model binary interaction parameters were obtained by measured tie-line values and minimizing an objective function. The consistency of the NRTL parameters was validated through topological analysis connected to the Gibbs tangent principle and stability test. Evaluation of the capacity of each solvent was performed using the calculation of distribution coefficients and separation factors. Distribution coefficient (constant) and selectivity (separation factor) values were evaluated over the immiscibility region using the experimental equilibrium data. The influence of extraction temperature on the immiscibility region was found to be minor.

Performance tuning of chitosan-based membranes by protonated 2-Pyrrolidone-5-carboxylic acid-sulfolane DES for effective water/ethanol separation by pervaporation

Today, the applicability of deep eutectic solvents (DES) in various fields, including membrane science and technology, is extensively investigated. In pioneering works, we have implemented different DES as a component of chitosan (CS)-based flat membranes for pervaporation (PV) separation. Herein, we present a new protonated (by sulphuric acid) 2-Pyrrolidone-5-carboxylic acid: sulfolane DES, as a green additive for its chemical blending and thus study its effect in CS structure. The resultant flat CS-based membranes have been characterized and tested for their ability in separating water molecules from ethanolic mixtures (10 wt% water in ethanol) using PV. Experiments revealed a progressive increase in total permeation along with increase of temperature in the range of 20–50 °C. Simultaneously, the value of separation factor was reduced. The maximum permeation (approximately 0.44 kg m−2 h−1) was observed for the highest experimental temperature, in which water was the main component, while the highest separation factor (approximately 518) was observed for lowest operating temperature. It was confirmed that application of selected DES allowed to improve the permeation rates in comparison with the bare CS membrane. As a perspective, such membranes could be tested for another hydrophilic pervaporation applications for the removal of polar compounds – with high applicability in biorefineries.

Multiple Heart-Cutting Two-Dimensional HPLC-UV Achiral–Chiral Analysis of Branched-Chain Amino Acids in Food Supplements under Environmentally Friendly Conditions

A multiple heart-cutting (mLC-LC) two-dimensional HPLC-UV achiral–chiral method for the direct analysis of branched-chain amino acids (BCAAs) in food supplements under environmentally friendly conditions was developed to cope with the very well-known limited chemoselectivity of chromatographic media for enantioselective analysis. Both achiral and chiral methods were developed in compliance with the main principles of green chromatography. The achiral analysis was performed isocratically with an optimized ion-pair reversed-phase (IP-RP) method based on a water/EtOH (95:5, v/v) mobile phase containing heptafluorobutyric acid (7 mM) as the IP agent. The achiral method was characterized by a very appreciable performance and was validated before the analysis of the real sample. High recovery values for all compounds (from 97% to 101%) were found in the interday evaluation. Additionally, low RSD% values in the long-term period were measured, in the range between 1.1% and 4.8%. Still, an LOQ value of 0.06 mg/mL was established for all compounds. The quantitative analysis of a commercial food supplement revealed that BCAAs were present in amounts very close to those declared by the producer. The enantioselective analysis was carried out through the application of the chiral ligand-exchange chromatography (CLEC) approach, using O-benzyl-(S)-serine ((S)-OBS, 0.5 mM) as the chiral selector and Cu(II) nitrate (0.25 mM) as the metal source in the eluent. Resolution and separation factor values up to 2.31 and 1.43, respectively, were obtained. The two chromatographic systems were connected through a six-port switching valve, and the developed two-dimensional mLC-LC method confirmed the absence of D-enantiomers of BCAAs in the food supplement, as reported in the manufacturer’s label.

A new route for ZIF-8 synthesis and its application in MMM preparation for toluene removal from water using PV process

Pervaporation (PV) is one of the most effective methods for removing volatile organic compounds (VOCs). The application of hydrophobic membrane in PV is of significant industrial value. This study used a novel method to synthesis hydrophobic zeolitic nanoparticles (ZIF-8) and incorporate them into the polymer matrix (PEBA). The prepared mixed matrix membranes (MMM) were characterized by various techniques (FTIR, FESEM, XRD, AFM, contact angle, TGA, and DSC) and utilized for toluene/water separation in a PV process. The operational findings in terms of separation factor, total permeate flux, component flux, and PSI value were studied for nanocomposites with different filler content (5–25 wt%) at different feed concentrations and temperatures. The best separation performance was achieved for MMM with 15% ZIF-8 at 30 °C and 300 ppm. The total flux enhanced from 302 to 343 gm2h compared to the neat membrane. In this condition, separation factor, and PSI value were obtained as 446, and 153120 gm2h, respectively. Incorporating of 15% hydrophobic ZIF-8 significantly improved separation factor, and PSI value by 904, and 1065%, respectively, compared to the pure membrane.

Highly Cross-Linked butene grafted poly (Vinyl Alcohol)–co-Vinyl pyridine based anion exchange membrane for improved acid recovery and desalination efficiency

Water treatment and waste acid reclamation are important in present situation due to huge industrialization. Different processes are available for the water treatment and waste treatment. Ion exchange membranes based electrodialysis (ED) and diffusion dialysis (DD) are attracted by the researchers since last decade due to its simplicity and economical operation. Acid reclamation by diffusion dialysis has been gained huge attention due to their absolute selectivity and energy less process. Here, we report the synthesis of efficient anion exchange membrane (AEM) by free radical co-polymerization of butene grafted poly (vinyl alcohol) and 4-vinyl pyridine followed by in-situ quaternization and cross-linking. Different amount 4-vinyl pyridine was chosen for the membrane preparation, and its impact on physiochemical and electrochemical properties has been studied. Structural and chemical characterisation of the membranes were studied using nuclear magnetic resonance (NMR), attenuated total reflectance-infrared spectroscopy (ATR-IR), while surface-phase morphology was investigated through scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermo-mechanical properties of prepared membranes were studied using thermogravimetric analysis (TGA), differential scanning colorimetry (DSC), dynamic mechanical analysis (DMA) and universal testing machine (UTM) analysis. The cross-linked PVA-x membranes showed high acidic stability as well as good antioxidation property. The synthesized membranes were studied for their salt removal performance by electrodialysis and acid recovery by diffusion dialysis. The optimised membrane (PVA-0.8) shows 0.90 kWh kg−1 energy consumption and 93.49 % current efficiency during salt removal from brackish water using electrodialysis. All cross-linked PVA-x membranes have diffusion coefficient of acid are in the range of 0.0556–0.0716 mh−1 and separation factor values are between the 79.51 to 91.33 at 25 °C, which comparable to commercial DF-120B membrane. This result shows that the prepared cross-linked AEMs may be a good candidate for the electrochemical applications.