Ionic Liquid Membranes Research Articles

Contrasting Miscibility of Ionic Liquid Membranes for Nearly Perfect Proton Selectivity in Aqueous Redox Flow Batteries

AbstractIon‐selective membranes are widely used in various energy storage applications. However, conventional polymer‐based ion‐selective membranes, such as Nafion, are not perfectly ion‐selective, leading to a significant permeation of undesirable ionic species. As the imperfect ion‐selectivity of membranes leads to the failure of energy storage devices, much effort is devoted to improving membrane ion‐selectivity. Herein, an immiscible liquid‐state membrane is introduced for aqueous redox flow batteries. As hydrophobic ionic liquids are immiscible with aqueous catholyte and anolyte solutions, they separate the two without crossover. This property renders them suitable for use as a membrane for aqueous redox flow batteries. In addition, ionic liquids with long side alkyl chains, such as 1‐hexyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM‐TFSI), are miscible with sulfuric acid, whereas transition metal sulfates remain insoluble in HMIM‐TFSI. For this reason, HMIM‐TFSI is selectively permeable to protons and remains impermeable to transition metal cations. As a result, the HMIM‐TFSI membrane is almost perfectly proton‐selective, leading to negligible permeability of unfavorable ionic species, such as transition metal cations. Eventually, the HMIM‐TFSI membrane shows the excellent electrochemical performance of vanadium redox flow batteries, such as negligible self‐discharge over 2800 h, high Coulombic efficiency (≈99%), and stable capacity retention over 100 cycles.

CO2/CH4 separation through monolayer nanoporous graphene oxide supported ionic liquid membrane

Nanoporous graphene oxide (NPGO) with a single atomic layer thickness and good mechanical strength has been regarded as a promising candidate in gas separation. However, it is challenging to precisely control the pore size to match the target gas. In this work, the pore size was modulated by supporting ionic liquid (IL) on the monolayer NPGO membrane (NPGO-SILM). The separation performance and mechanism for CO2/CH4 in NPGO-[EMIM][BF4], NPGO-[EMIM][PF6] and NPGO-[EMIM][TF2N] were investigated by molecular dynamics simulation. It was found that the pore size of NPGO greatly affects the permeability and selectivity, and 5.6 Å is the most suitable pore size. After coating IL on NPGO, the CO2/CH4 selectivity is obviously enhanced. With the IL thickness increasing from 5 to 11 Å, the CO2 permeance decreased from ∼105 to ∼104 GPU, while the selectivity increased, and almost no CH4 passed through the membrane with 11 Å thickness. Among the studied three types of ILs, the NPGO-[EMIM][TF2N] membrane shows the best CO2/CH4 separation performance due to the strongest adsorption capacity between [TF2N] anion and CO2. The interaction energy, PMF and probability distribution results suggest that the improved selectivity is attributed to the synergistic effect of cations and anions. The anions are responsible for the adsorption of large amounts of CO2. At the same time, the cations are mainly distributed around the center of the NPGO pore because of the strong interaction between cation and NPGO, which would be favorable for dynamically adjusting pore size to allow the passage of CO2 and prevent CH4 from passing through the membrane.

Supported ionic liquid membrane contactor with crown ether functionalized polyimide membrane for high-efficient Li+/Mg2+ selective separation

Worldwide demand for lithium is increasing rapidly. Implementing an efficient extraction for lithium from salt-lake brines with low concentration and high Mg/Li (m/m) ratio remains challenging. A supported ionic liquid membrane (PI@14C4-SILM) contactor was developed in this work using a crown ether functionalized polyimide membrane material (Poly(DAB14C4-6FDA)) as the support and tributyl phosphate (TBP) and (1-butyl-3-methylimidazolium bis-trifluoromethylsulfonimide salt) ([C4mim][NTf2]) mixture as the liquid phase for high-efficiency Li recovery. The results show that when the feed phase Mg/Li ratio is 35 and the stripping phase is 0.5 mol/L HCl, the Li+ penetration rate, initial flux and Li/Mg selectivity of PI@14C4-SILM contactor are 0.354 μm/s, 0.128 mol/m2·h and 19.1, respectively. Molecular dynamics (MD) simulation results show that Poly(DAB14C4-6FDA) and TBP have greater interaction with Li+ than other ions (Na, Mg, K). Meanwhile, the binding energies of Poly(DAB14C4-6FDA)-Li-NTf2 and TBP-Li-NTf2 were calculated by density functional theory (DFT), which were −163.26 and −182.1 kcal/mol, respectively. The higher binding energies of the complexes indicated that their structures were more stable. The mechanism of the PI@14C4-SILM contactor's excellent Li+ mass transfer performance may be the formation of a fast Li+ transfer channel between the solid phase containing the crown ether structure and the liquid mobile phase in the pore structure. Besides, the TBP·Li·NTf2 and TBP·H·NTf2 structures in the liquid membrane phase effectively maintained the cyclic operation of the SILM system. This study provides an effective solution for selective separation of Mg/Li and utilization of Li resources in salt lake water.

Efficient removal of Cr (VI) from wastewater using recycled polymer-based supported ionic liquid membrane technology

Hexavalent chromium (Cr (VI)) is a hazardous form of chromium that poses a significant threat to human health and the environment. Meanwhile, Polyethylene Terephthalate (PET) bottles, despite their widespread use and practicality, contribute substantially to the plastic waste problem. Converting waste PET bottles into polymeric membranes offers significant promise. Supported ionic liquid membrane (SILM) technology is a relatively new technique that shows the potential to treat contaminated water efficiently. Experimental studies have demonstrated the influence of different operating conditions on Cr (VI) separation using SILM. The key parameters include concentrations of the feed phase, carrier (Aliquat 336), and strip phase (HCl) and their interactions. Around 98% of Cr (VI) can be removed at a feed concentration of 25 mg/l, a carrier concentration of 5%, and 0.5 M of HCl as a stripping agent. The optimal carrier concentration for membrane extraction was 5% (v/v), leading to a maximum removal rate of 98.34% at optimized values. To assess the impact of carrier concentration on the membrane, SEM-EDS mapping was done. The successful wastewater treatment from such an innovative approach enables handling plastic management and water pollution.

1D-2D intercalated network CMC@g-C3N4/IL membrane with high permeability and selectivity for the CO2 capture

The structural advantages of the membrane material itself are critical to the membrane separation performance. Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanosheets can achieve minimal mass-transfer barrier and high gas sieving performance due to their ultra-thin thickness, inherent surface porosity and abundance of amine groups. However, the 2D g-C3N4 nanosheets are prone to stacking during the self-assembly process, which reduces the membrane permeability. Based on this line, herein, we proposed a concept of construction of 1D-2D intercalated network supported ionic liquid membrane composed by one-dimensional (1D) carboxymethylcellulose (CMC) and g-C3N4 nanosheets to overcome the low permeability of 2D graphitic carbon nitride membrane in separating CO2/N2 and CO2/CH4. The as-prepared 1D-2D intercalated network supported ionic liquid gas separation membrane exhibits superior CO2 permeance of 953.96 GPU, CO2/N2 selectivity of 55.46 in separation of CO2/N2, and CO2 permeance of 854.00 GPU, CO2/CH4 selectivity of 50.62 in separation of CO2/CH4. In addition, the resulting CMC@g-C3N4/IL membrane has excellent durability. After 120 h of testing, it still has outstanding separation performance. In short, this concept in this study provides an effective modulation of molecular sieving of g-C3N4 membrane for high-efficiency CO2 capture by combination of the advantages of the 1D (CMC) and 2D (g-C3N4) materials.

Enhancing CO2 separation from N2 mixtures using hydrophobic porous supports immobilized with tributyl-tetradecyl-phosphonium chloride [P44414][Cl

The main obstacles in adopting solvent-based CO2 capture technology from power plant flue gases at the industrial scale are the energy requirements for solvent regeneration and their toxicity. These challenges can be overcome using new green and more stable ionic liquids (ILs) as solvents for post-combustion CO2 capture. In the current study, tributyl-tetradecyl-phosphonium chloride [P44414][Cl] as an IL, was immobilized on hydrophobic porous supports of polypropylene (PP), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) at 298 ± 3 K and pressures up to 2 bar. The surface morphology indicated homogenous immobilization of the IL on the membrane support. Supported ionic liquid membranes (SILMs) were tested for CO2 permeability and CO2/N2 selectivity. None of the SILMs exhibited IL leaching up to 2 bar. The PTFE-based SILM performed better than other supports with minimum loss in water contact angle (WCA) and achieved good antiwetting with a maximum CO2 permeability and selectivity over N2 of 2300 ± 139 Barrer and 31.60 ± 2.4, respectively. This work achieves CO2 permeability about two-fold more than other works having CO2/N2 selectivity range of 25–35 in similar SILMs. The diffusivity of CO2 and N2 in [P44414][Cl] was measured as 3.64 ± 0.18 and 2.01 ± 0.09 [10−8 cm2 s−1] and CO2 and N2 solubility values were 9.79 ± 0.47 and 0.19 ± 0.001 [10−2 cm3(STP) cm−3 cmHg−1], respectively. The high values of Young's modulus and tensile strength of the PTFE support-based SILM (234 ± 12 MPa and 6.07 ± 0.31 MPa, respectively) indicated the long-term application of SILM in flue gas separation. The results indicated phosphonium chloride-based ILs could be better solvent candidates for CO2 removal from large volumes of flue gases than amine-based ILs.

Hydroxyapatite and ionic liquid coupled with hybrid membranes for toxic pollutant removal and remediation

Access to clean water is the mandatory requirement for every living being to sustain life. So, membrane-based integrated approach of adsorption and separation technology has recently been preferred by scientists over other conventional techniques, for wastewater treatment. Current research focused on the synthesis of novel imidazolium (A1) based IL, which was further functionalized with hydroxyapatite (HAp; extracted from Labeo rohita scales), to create possible solutions towards environmental remediation. Cellulose acetate (CA) was used for the fabrication of three different ionic liquid membranes. All the synthesized products were characterized by FTIR, XRD and TGA. Two dyes of different nature, i.e., congo red (anionic) and crystal violet (cationic) were selected because of their highly toxic and carcinogenic effects, for batch adsorption experiments. Antibacterial activity of the synthesized membranes was also evaluated against S. aureus. Results of the study revealed that CA-HA1 1:2 acted as the best adsorbent towards the removal of crystal violet, exhibiting removal efficiency of 98% with the contact time of 24 h while in case of congo red adsorption, CA-HA1 (1:2) proved as prime adsorbent with the removal efficiency of 96% for the same preceding contact time. Considering the antibacterial character of the synthesized membranes, CA-A1 (1:1) emerged as very efficient antibacterial agent with the inhibition zone of 50 mm after 48 h. The overall behavior of monolayer and multilayer adsorption was witnessed for both dyes while kinetic studies favored the pseudo-second order reaction for all adsorbents.

High flux novel polymeric membrane for renal applications

Biocompatibility and the ability to mediate the appropriate flux of ions, urea, and uremic toxins between blood and dialysate components are key parameters for membranes used in dialysis. Oxone-mediated TEMPO-oxidized cellulose nanomaterials have been demonstrated to be excellent additives in the production and tunability of ultrafiltration and dialysis membranes. In the present study, nanocellulose ionic liquid membranes (NC-ILMs) were tested in vitro and ex vivo. An increase in flux of up to two orders of magnitude was observed with increased rejection (about 99.6%) of key proteins compared to that of polysulfone (PSf) and other commercial membranes. NC-ILMs have a sharper molecular weight cut-off than other phase inversion polymeric membranes, allowing for high throughput of urea and a uremic toxin surrogate and limited passage of proteins in dialysis applications. Superior anti-fouling properties were also observed for the NC-ILMs, including a > 5-h operation time with no systemic anticoagulation in blood samples. Finally, NC-ILMs were found to be biocompatible in rat ultrafiltration and dialysis experiments, indicating their potential clinical utility in dialysis and other blood filtration applications. These superior properties may allow for a new class of membranes for use in a wide variety of industrial applications, including the treatment of patients suffering from renal disease.

Stabilization of [BMIM][PF6] ionic liquid membrane in structurally optimized multilayer ceramic support through aqueous DEA solution for CO2/CH4 separation

The stability of the ceramic supported liquid membranes (SLMs) is one of the most interesting research subjects. In this work, the SLMs’ stability for CO2/CH4 separation was investigated. Following pressing α-Al2O3 substrates at 400, 600, and 800 bar, colloidal and polymeric TiO2 intermediate and top layers were coated. Aqueous diethanolamine (DEA) solution was used as solvent in the SLM to optimize support structure based on CO2/CH4 separation performance. The pressed support at 800 bar and coated with TiO2 demonstrated best performance and selected for further study. Subsequently, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid (IL) was immobilized inside the selected support and used as the supported ionic liquid membrane (SILM) for CO2/CH4 separation. The SILM separation performance was evaluated under different pressures and temperatures. Temperature was found to has greater effect than pressure due to a decrease in IL's viscosity and an increase in penetrant diffusivity. At 25 °C and 1 bar, SILM exhibited consistent and reliable performance as CO2 and CH4 permeabilities of 244.0 and 7.4 Barrer, respectively, and CO2/CH4 selectivity of 33.0 over 6 h. The findings contribute to understanding the implementation of multilayer ceramic SILMs for CO2/CH4 separation and highlight its potential along with opening up new avenues.

Theoretical study of supported ionic liquid membrane reaction and transport for CO2 cycloaddition reaction

Membrane reactors are promising for achieving a variety of thermodynamically limited reactions. However, few studies have focused on quantitative analysis of the coupling of reaction and separation matching of membranes. In this work, based on the experimental validation of the forced flow through principle of membrane reactors for catalytic CO2 cycloaddition, describes the membrane reaction performance of supported ionic liquid membranes (SILMs) in the presence of primary irreversible reactions, and draws on a dusty gas model to calculate fluxes within the gas pore space of the support. The degree of product separation is theoretically investigated in relation to the membrane permeation, the resistance difference between the ionic liquid membrane and the support, the liquid loading of the catalyst layer and the fluid flow rate, and adjustable parameters of the model are proposed to predict the SILM performance. In addition, two dimensionless numbers, namely Damköhler (Da) and Péclet (Pe) numbers, are introduced to correlate the equilibrium constant-conversion-DaPe relationship, and the reaction kinetics and permeate flux compatibility are analyzed with the help of CFD simulations, which incorporate parameters of operating conditions and stoichiometric coefficients of the reaction, as well as optimization of reactor geometrical, providing insights to achieve higher conversion improvements.

Gas dehumidification over supported nicotine-based ionic liquid membranes: Effect of alkyl chain length and ether group presence

In this work, supported nicotine-based IL membranes were synthesized and the effect of alkyl chain length and ether groups presence was examined on physicochemical as well as gas and water vapor separation properties. Gas permeation is mainly affected by diffusion, while solubility is the main factor for water vapor permeation. For this reason, alkyl chain lengthening contributed to the increase of all gas (CO2, CH4, N2) permeabilities due to IL viscosity reduction, while water vapor permeability decreased because of the concomitant increase in hydrophobicity. On the other hand, the membrane containing IL with ether groups exhibited the highest water vapor permeability of 141,000 Barrer with a H2O/CH4 selectivity of 126,000 and a H2O/N2 selectivity of 117,000. These permeation properties, which are the highest relative to other reported SILMs with TFSI- as counter anion, remained unchanged even under mixed gas/water vapor conditions, showing the potential for dehumidification processes.

Removal of low concentration ibuprofen using green diluent and novel formulated supported ionic liquid membrane

Removal of pharmaceutical micropollutants is critical to reduce detrimental contaminants found in the environment. The current study focuses on developing a new formulation of supported ionic liquid membrane (SILM) for removing low concentration of ibuprofen (IBP) using green diluent and ionic liquid. Parameters such as solid support properties, variation of diluents, type of carrier and carrier concentration are investigated. The results demonstrate that liquid carrier consisted of sunflower oil (SFO) and Aliquat 336 successfully impregnated on the PVDF support via FTIR and SEM analysis. Liquid carrier loss from the PVDF support is less than 1% by impregnating green diluents consisting of SFO. 18PVDF-DMAC/300 is selected owing to its asymmetric finger-like and spongy structure with porosity, mean pore diameter, contact angle and thickness of (82.2 ± 0.7) %, (0.19 ± 0.01) μm, (89.4 ± 0.2)° and (90.3 ± 0.8) μm, respectively. Under 72-hour operation, a maximum extraction and stripping efficiency are obtained at 93% and 87% respectively, indicating a stable SILM process. Results obtained suggest that the newly formulated SILM is advantageous and may be used to extract low concentrations of IBP from the feed phase.

Novel-supported ionic liquid membranes for an effective removal of pentachlorophenol from wastewater

Recently ionic liquids (ILs) have been useful in many areas of wastewater treatment and separation processes in environmental engineering, such as supported ionic liquid membranes (SILM) based separations and solvent extraction applications. In this work novel ILs, namely 1-butyl-2,3-dimethyl imidazolium hexafluorophosphate [C4DMIM][PF6], tetrabutyl–phosphonium exafluorophosphate [TBP][PF6] were immobilized on PVDF (polyvinylidene fluoride) membrane for the removal of organic pollutant such as pentachlorophenol (PCP) from the water phase by SILM. Operating conditions like pH, feed and permeate concentration, membrane flux, and the mechanism was also studied. The interactions of H+ bonding, hydrophobic interactions, and carbon–π bonding interactions are explained via the SILM transport mechanism. The membranes were characterized by SEM, EDX, and FTIR analysis. In the experimental study, a high zetapotential of −93.24 mV was achieved, which is an indication of the excellent stability of SILM. At a pH of 4, [TBP][PF6] had the highest penetration rate of 87%. In contrast, [C4DMIM][PF6] yielded 79% after 30 h of experimentation at the feed pH 4. Similarly, after 30 h, [TBP][PF6] got the highest rate of permeation (80.50%), followed by [C4DMIM][PF6] (73.00%). The 0.1 M NaOH was used as a stripping agent in this study. PCP was successfully separated from the aqueous phase using two different hydrophobic ionic liquids as [C4DMIM][PF6] and [TBP][PF6]. This SILM technique has the potential in the future for further developments and for extracting organic contaminants from wastewater on a laboratory or industrial scale.

Current status of CO2 capture with ionic liquids: Development and progress

Global warming triggered by greenhouse gas (GHG) emissions, particularly carbon dioxide (CO2), significantly influences climate change and has become a common environmental issue recently. The current amine-based technologies (ABTs) for CO2 capture (CAPCO2) have high energy demand, low absorption, and desorption rates, and are less environmentally sustainable due to high emissions of volatile solvents. Therefore, the development of environmentally friendly CAPCO2 materials and/or processes is a growing area of research. The utilization of ionic liquids (ILs) for CAPCO2 has recently attracted attention. The unique characteristics of ILs, such as their low vapor pressure and high affinity for CAPCO2 as well as their low volatility make them a viable substitute for the existing processes. This work provides a comprehensive overview of the accomplishments and challenges during the use of ILs for CAPCO2. The Review also outlines the mechanisms of the CAPCO2 with ILs at the molecular level, the properties of ILs, characterization of the CO2/IL systems, and the effect of operating conditions on CO2 uptake (UPCO2) capacity by ILs. It also emphasizes the impact of cations, anions, and functional groups on the solubility of CO2 ((SCO2)) in ILs as well as the biodegradability and toxicity of ILs. Additionally, recent advances in IL membrane technology for the CAPCO2 processes are considered. Lastly, the contribution of molecular simulations to create and assess ILs was reviewed. Protic and aprotic ILs properties have shown outstanding efficiency of UPCO2. The interactions between the anionic part of IL and CO2 enhance the UPCO2 and outperform the efficiency of traditional organic solvents. Functionalized ionic liquids (FUNILs) with tuned functional groups, supported ionic liquids membranes (SILMs) as well as reversible ionic liquids (RILs) have improved the efficiency of ILs as a promising CO2 capturing process from industrial streams even under low CO2 partial pressure. The relative importance of the chemical breakdown of the IL constituents (cation–anion interfacial structuring) during the CAPCO2 process at different operating temperatures is unclear, and more research in this area is required to better inform the design of new ILs. This review provides a proper/systematic guideline to help ILs manufacturers and engineers design high-capacity ILs for appropriate CAPCO2.

Performance Evaluation of Supported Ionic Liquid Membranes (SILMs) Derived from Optimized PES/PDMS/ZIF-L Composites for CO2 Separation

Performance Evaluation of Supported Ionic Liquid Membranes (SILMs) Derived from Optimized PES/PDMS/ZIF-L Composites for CO₂ Separation

Ionic Liquid-Based Green Emulsion Liquid Membrane for the Extraction of the Poorly Soluble Drug Ibuprofen

Ibuprofen (Ibf) is a biologically active drug (BADs) and an emerging contaminant of concern (CECs) in aqueous streams. Due to its adverse effects upon aquatic organisms and humans, the removal and recovery of Ibf are essential. Usually, conventional solvents are employed for the separation and recovery of ibuprofen. Due to environmental limitations, alternative green extracting agents need to be explored. Ionic liquids (ILs), emerging and greener alternatives, can also serve this purpose. It is essential to explore ILs that are effective for recovering ibuprofen, among millions of ILs. The conductor-like screening model for real solvents (COSMO-RS) is an efficient tool that can be used to screen ILs specifically for ibuprofen extraction. The main objective of this work was to identify the best IL for the extraction of ibuprofen. A total of 152 different cation-anion combinations consisting of eight aromatic and non-aromatic cations and nineteen anions were screened. The evaluation was based upon activity coefficients, capacity, and selectivity values. Furthermore, the effect of alkyl chain length was studied. The results suggest that quaternary ammonium (cation) and sulfate (anion) have better extraction ability for ibuprofen than the other combinations tested. An ionic liquid-based green emulsion liquid membrane (ILGELM) was developed using the selected ionic liquid as the extractant, sunflower oil as the diluent, Span 80 as the surfactant, and NaOH as the stripping agent. Experimental verification was carried out using the ILGELM. The experimental results indicated that the predicted COSMO-RS and the experimental results were in good agreement. The proposed IL-based GELM is highly effective for the removal and recovery of ibuprofen.

CO2 Separation Using Supported Deep Eutectic Liquid Membranes Based on 1,2-propanediol

In this work, deep eutectic solvents (DESs) composed of choline chloride, acetylcholine chloride or tetrabutylammonium chloride, and 1,2-propanediol were used as a liquid phase for polypropylene-based supported liquid membranes (SLMs) and evaluated for the separation of carbon dioxide from CO2/N2 mixtures. Fourier transform infrared spectra were obtained to confirm DES formation, and the thermal stability of solvents was investigated using thermogravimetric analysis. The physicochemical properties of DESs and carbon dioxide solubility were determined in a temperature range of 293.15–313.15 K. The effects of the hydrogen bond acceptor structure and the acceptor/donor molar ratio in regard to properties and CO2 separation potential were discussed. The permeability of CO2 and N2 in DES-based SLMs was determined, and the ideal CO2/N2 selectivity was calculated. The gas permeation results of the 1,2-propanediol-based DES-based supported liquid membranes showed that the permeability of CO2 varied from 86 to 152 barrers in 293.15 K. Similarly, the ideal CO2/N2 selectivity varied from 21 to 30. The performance of DES–SLMs was compared with the competing imidazolium-based supported ionic liquid membranes and proved DES–SLMs as a promising alternative considering their green potential and comparable gas separation performance.

Efficient CO2/CH4 separation using [Bmim][Ac]/Pebax-1657 supported ionic liquid membranes and its prediction by density functional theory

The world's daily increase in population has become ravenous for natural resources for energy and potentially helps to become the main reason for causing global climate change. Carbon dioxide (CO2) is one of the critical elements of the greenhouse gas effect, as we all know. Last few decades, researchers have been much interested in CO2 capture and storage technologies. From such technologies, membrane separation has some good results in CO2 capture compared to others. In this investigation, ionic Liquid (IL) supported membranes were used to separate CO2 and methane (CH4) gas mixtures. The Pebax-1657 with 1-Butyl-3-methylimidazolium acetate concentrations 5%, 10%, 20% (wt.%, based on polymer) were prepared for gas separation study. Density functional theory (DFT) computations were also used to estimate CO2 and CH4 interactions with the IL. These membranes are examined for analytical and morphological research using various characterization methods such as FTIR and scanning electron microscopy. As expected, the gas separation results show that mixed gas selectivity (CO2/CH4) increases at high-pressure values due to the addition of IL. Membrane with 20 wt.% concentration (based on polymer) IL shows higher permeability and CO2/CH4 selectivity.

Biocompatible cellulose acetate supported ammonium based ionic liquid membranes; way forward to remediate water pollution

Dyes contaminated water has caused various environmental and health impacts in developing countries especially Pakistan due to different industrial activities. This issue has been addressed in present study by fabricating biocompatible ionic liquid (IL) membranes for the remediation of Crystal violet (CV) dye from contaminated water. Novel ammonium-based IL such as Triethyl dimethyl ammonium sulfate ([C3A][C2H6]SO4); (A2) was synthesized and further functionalized with hydroxyapatite (HAp; extracted from refused fish scales) resulting in the formation of HA2. Furthermore, A2 and HA2 were then used to fabricate the cellulose acetate (CA) based membranes with different volume ratios. The physicochemical properties of membranes-based composite materials were investigated using FTIR, XRD, and TGA and used for the adsorption of CV in the closed batch study. In results, CA-HA2 (1:2) showed higher efficiency of 98% for CV reduction, after the contact time of 90 min. Kinetic studies showed that the adsorption of CV followed the pseudo-second-order kinetic model for all adsorbents. The antibacterial properties of the synthesized membrane were investigated against gram-positive strain, S. aureus and CA-A2 (1:1) showed better antibacterial properties against S. aureus. The developed membrane is sustainable to be used for the adsorption of CV and against bacteria.

Ion transfer voltammetric and LC/MS investigations of the oxidative degradation process of fentanyl and some of its structural analogs

Ion transfer voltammetry at a polarized ionic liquid membrane and LC/MS technique were used to investigate the oxidative time-resolved degradation of the frequently (mis)used opioid fentanyl and some of its structural analogs.The degradation is based on the reaction of opioids with hydroxyl radicals produced by the catalytic decomposition of hydrogen peroxide. Using the voltammetric technique, it was confirmed that the presence of Fe2+ions and hydrogen peroxide is essential in the degradation process of fentanyl(s). An increasing concentration of ferrous ions accelerates the described reactions, while the reaction rate is much less affected by the concentration of fentanyl.In an excess of ferrous ions, the course of the reaction can be approximated by a pseudo-first-order reaction with a half-time of 3.85 min. The generation of HO• radicals was proved to be the rate-determining step. Oxidative degradation processes of all investigated fentanyl-related drugs exhibit similar kinetics. A wide variety of fentanyl degradation products were detected and characterized using LC/MS analysis. Mono-, di- and trihydroxylated derivatives in several isomeric forms were observed most abundantly in a relatively short reaction time (5–30 min). The formation of norfentanyl has also been demonstrated.