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Deep eutectic solvents (DES), a new class of alternative solvents, have recently been used in the pre-treatment of lignocellulosic biomass. Due to the ability to dissolve phenolic compounds, they have been efficiently applied as delignification agents. However, to extend DES application to bioprocesses, such as Anaerobic Digestion (AD), their toxicity to microbial consortia must be evaluated. In this work, an effective delignifying DES, composed of choline chloride (ChCl) and oxalic acid (OA) (1:1) was prepared and its effect evaluated, for the first time, in biogas production. Results show that the presence of DES had both beneficial and detrimental effects on the anaerobic consortium, depending on its concentration. In the concentration range of 0.3–12.5 g/L, the presence of DES led to a lag-phase of 1 to 8 d as the DES concentration increased. However, after the lag-phase has been surpassed, DES up to a concentration of 12.5 g/L improved the biogas production, reaching an accumulated biogas volume three times higher than the control assay for the concentration of 12.5 g/L. For the highest DES concentrations (19.8–78.1 g/L), the biogas production was inhibited. The assays performed with DES components alone have indicated that OA at 3.2 g/L was the main responsible for the inhibition of biogas production (50% less biogas produced than the control). ChCl at 4.9 g/L has not presented a lag-phase and produced an accumulated biogas volume like the control assay (1200 mL for 30 d incubation). This work points out that ChCl:OA DES may be used in the delignification of biomass further submitted to AD, provided the inhibitory concentrations of OA are not achieved.

Aiming at providing a new solution for processing and recycling PET, the complete solubilization of PET from water bottles in natural eutectic solvents is demonstrated here as well as its full recovery, while retaining PET properties and recycling the eutectic solvent.

In recent times, deep eutectic solvents (DES) have received attention as an extractive media for separations. In this work, the water stability of eight menthol-based DESs and two tetrabutylammonium chloride (N

Owning to its unique properties of breaking down proteins into soluble small peptides, pepsin has been advantageously applied in many different industries, such as food, feed, or pharmaceuticals. H...

Femtosecond (fs) laser micromachining on polymeric materials is a single-step, and contactless manufacturing technology. Knowing the potential of poly(ionic liquid)s (PILs) and their derived composite materials incorporating ionic liquids (PIL–IL) to design membranes with improved CO2 separation, we here explore for the first time the creation of microchannels on the surface of PIL–IL materials by laser ablation using femtosecond laser radiation. PIL–IL membranes composed of pyrrolidinium-based PILs containing the [NTf2]– and [C(CN)3]– anions and different amounts of their corresponding ILs (40 and 60 wt%) were prepared and micromachined using fs laser pulses varying the pulse repetition rate, scanning speed, and pulse energy. The morphology of the fs laser modified PIL–IL samples was investigated through scanning electron microscopy (SEM), while the influence of the fs laser processing on the membranes structure was analyzed by solid-state nuclear magnetic resonance (ssNMR), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The CO2/N2 and CO2/H2 separation performances of the irradiated membranes were also evaluated and compared to those of the non-irradiated. Depending on the parameters used, fs laser processing was successful in modifying the surface of PIL–IL membranes through the formation of microchannels around 55–60 μm deep. Significant improvements in CO2, N2 and H2 permeabilities were achieved for the irradiated PIL–IL membranes, maintaining their CO2/N2 and CO2/H2 permselectivities.

This work aims to explore the gas permeation performance of two newly-designed ionic liquids, [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2], in supported ionic liquid membranes (SILM) configuration, as another effort to provide an overall insight on the gas permeation performance of functionalized-ionic liquids with the [C2mim]+ cation. [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] single gas separation performance towards CO2, N2, and CH4 at T = 293 K and T = 308 K were measured using the time-lag method. Assessing the CO2 permeation results, [C2mim][CF3BF3] showed an undermined value of 710 Barrer at 293.15 K and 1 bar of feed pressure when compared to [C2mim][BF4], whereas for the [C2mim][CF3SO2C(CN)2] IL an unexpected CO2 permeability of 1095 Barrer was attained at the same experimental conditions, overcoming the results for the remaining ILs used for comparison. The prepared membranes exhibited diverse permselectivities, varying from 16.9 to 22.2 for CO2/CH4 and 37.0 to 44.4 for CO2/N2 gas pairs. The thermophysical properties of the [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] ILs were also determined in the range of T = 293.15 K up to T = 353.15 K at atmospheric pressure and compared with those for other ILs with the same cation and anion’s with similar chemical moieties.

Liquid–liquid phase behavior measurements were performed for binary mixtures of water and ionic liquids (ILs) containing the same 1-ethyl-3-methylimidazolium ([C2mim]+) cation and different imide-based anions, having symmetric (bis(fluorosulfonyl)imide ([FSI]−)) or asymmetric structures (2,2,2-trifluoromethylsulfonyl-N-cyanoamide ([TFSAM]−) and 2,2,2-trifluoro-N-(trifluoromethylsulfonyl)acetamide ([TSAC]−)). An inversion of phase behavior was observed: while below ∼298 K, the miscibility of water in the studied ILs increases according to the order [C2mim][TSAC] < [C2mim][FSI] < [C2mim][NTf2], for temperatures above ∼303 K, the reverse trend is observed [C2mim][NTf2] < [C2mim][FSI] < [C2mim][TSAC]. In turn, above ∼306 K the [C2mim][TFSAM] is completely miscible with H2O in all ranges of concentrations. The obtained results also revealed an unusual water solubility variation of 11% in [C2mim][FSI], and 20% in [C2mim][TSAC], when the system temperature was changed by less than 1 K, around 298 K and 301 K, respectively. Molecular Dynamics (MD) simulations were used to understand the IL–water interactions and rationalize the experimental observations. These results suggested that the miscibility trends are mainly related to the ability of the water molecules to form water–anion and water–water aggregates in solution.

Background: Eutectic solvents are a mixture of two compounds which possess a lower melting temperature than the parent compounds, using quaternary ammonium salts, such as choline chloride and betaine hydrochloride and organic acids, polyols and amides as hydrogen bond donors. These solvents can be an alternative as non-aqueous media for enzymatic reactions, mainly using lipases. Objective: The objective of this work is to evaluate enzymatic activity and stability of commercial lipases, immobilized or at free form (Thermomyces lanuginosus: Lipozyme TL IM, iTL and Lipolase 100 L, fTL; Candida antarctica: Novozym 435, iCALB; Novozym 735, iCALA and Novozym CALB L, fCALB); and a phospholipase (Lecitase Ultra), in the presence of eutectic solvents (choline chloride ChCl:urea, ChCl:glycerol, betaine hydrochloride (BeHCl):urea and BeHCl: glycerol. Methods: Initially, lipases were maintained for 2 hours in solutions of choline and betaine-based eutectic solvents (1 to 20% m/m) at 25ºC compared with water for relative enzymatic activity. Using the solvent that best promoted lipase activity, some parameters were evaluated such as the molar ratio between quaternary ammonium salts and urea, stocking temperature and kinetics. Results and Conclusion: These eutectic solvents enable, mainly with immobilized lipases, 25 to 125 times more activity than water at 25ºC and 2h, and even after 24h, lipase iTLL was still 40 times more active in the presence of ChCl:Urea 1:3. Lipase iCALB showed great thermostability 47 times higher at 55ºC, almost double relative activity at 25ºC in the presence of BetHCl:Urea 1:4.

Clean water became one of the major concerns of the 21st century. The occurrence of micropollutants in aquatic ecosystems poses serious public health and environmental problems, leading to true challenges in the development of sustainable and cost-effective alternative technologies for wastewater treatment processes. As a result, hydrophobic deep eutectic solvents (DESs) have been emerging as easy-to-prepare, inexpensive, and environmentally benign media showing a high potential for water applications. The main goal of this work is the development of hydrophobic DESs for the removal of ciprofloxacin, identified as one of the top 10 priority micropollutants, from water environments. In particular, DESs composed of natural neutral components, such as menthol and fatty acids, and also DESs based on the combination of quaternary ammonium salts and natural fatty acids were evaluated as potential extractants. The molar ratio of C12:C10 displays the second highest solubility value of ciprofloxacin and the lowest...

In the last couple of years, deep eutectic solvents (DESs) have been raising a lot of attention mainly due to their versatility and their easy and speedy preparation without the need of further purification. Moreover, the vast array of very different compounds that can be selected for their preparation has led to the full tailoring of their relevant properties as solvents. We herein leave our opinion on the current challenges and opportunities in this blossoming field, which are curiously aligned with the scope of today's major concerns, where DESs are called to make a valuable contribution to important areas such as clean water, clean energy, and biotechnology.

The concurrent removal of both nitrogen- and sulfur-containing compounds, from simulated fossil fuels, was studied in this work. Four different deep eutectic solvents (DES) were prepared and ranked...

Graphical abstract, Highlights • Hydrophobic deep eutectic solvents showed to be effective for carotenoids recovery. • Ultrasound assisted extraction has improved recovery of β-carotene. • At optima conditions UAE extract of high-quality extract was obtained. • Carotenoids content, β-carotene, in extract was preserved. • Solvent polarity switch enabled carotenoids separation from the solvent., The aim of the present research was to develop green and sustainable extraction procedure for β-carotene recovery from pumpkin. A series of hydrophobic natural deep eutectic solvents (NADESs) based on fatty acids were prepared to establish high extraction efficiency of β-carotene and to increase stability of extracted carotenoids from the pumpkin. To intensify extraction process, NADES composed of C8 and C10 fatty acids (3:1) was selected and coupled with ultrasound assisted extraction. Response surface methodology and artificial neural network model (ANN) model was adopted to analyze significance of extraction parameters demonstrating high prediction levels of the β-carotene yield, experimentally confirming the maximum β-carotene content of 151.41 µg/mL at the optimal process condition. Extracted carotenoids in the optimal NADES extract have shown high stability during the storing period of 180 days. A switchable-hydrophilicity eutectic solvent system has been introduced as a successful way to recover extracted carotenoids from the NADES solvent. It was capable of precipitating 90% of carotenoids present in the extract. The proposed procedure is simple, easily scalable and has minimal impact on operators and the environment.

in a Volatile, Uncertain, Complex and Ambiguous (VUCA) World, Higher Education (HE) has been described as Super-complex. New complexities lead to new solutions, such as the rising relevance of soft skills in HE offers worldwide. Psychological Theories, in particular Self-Regulated Learning (SRL) and motivational theories offer new pathways to support change and development and are integrated and briefly reviewed in this paper. An example of a Portuguese Engineering School in the process of changing its' pedagogical model is explored in order to highlight the potential of specific psychological concepts in order to promote and support change in HE.

This paper summarizes the work of CAMEPP, the IST Commission that was charged in 2018 with the analysis of pedagogical practice at IST, as well as of the curricula of its first and second cycle degrees. As a consequence of this work, IST changed significantly the curricular structure of its degrees and pedagogical methods, with a new design that will begin its implementation in 2021/22.

M13 bacteriophage is a key instrument in phage display applications, as well as a possible antibacterial therapeutic agent due to its highly restrictive bacterial pathogenesis, and other applications. The traditional phage purification process is usually achieved by gradient ultracentrifugation or a combination of precipitation, centrifugation and microfiltration. These approaches easily lead to long process times, high operational costs, phage aggregation and consequent product loss (approximately 60%). This work is thus focused on an alternative potential large-scale process to achieve high yield and purity while minimizing the operational costs. Electrostatic-based separation processes are also common biomolecules purification techniques. Although anion exchange chromatography has been used before to purify several viral particles, this technique has been poorly reported for the purification of M13 phage. In a recent work, our group has demonstrated the use of a predominant anion exchange process, where a polymeric ionic liquid (PIL) was used as an alternative separation matrix for M13 bacteriophage. In this work, a variety of system parameters was studied, including chemical structure of the cation and the anion, the crosslinker nature and its concentration, either in batch adsorption/elution or chromatographic operation mode. The PIL-based chromatographic operation mode revealed to be a suitable separation process for M13 from directly filtered E. coli supernatant, reaching over 70% M13 recovery and 4.6 purification factor in a single step. To our knowledge, this is the first time that PILs have been reported as separation agents for bioproducts from complex mixtures.

The majority of antibiotics display low oral bioavailability due to reduced solubility in water and/or inefficient permeability across biological membranes. Their efficiency is further limited by the frequent presence of polymorphic structures with different pharmaceutical activities. In this communication, we present our latest results on the development of organic salts and ionic liquids from fluoroquinolones (FQ-OSILs) as highly efficient ionic formulations of this family of antimicrobials. Ciprofloxacin and norfloxacin were used as anions and as cations, by combination with biocompatible organic counter-ions. In vitro bioavailability studies showed that all prepared FQ-OSILs presented higher solubility in water than the original drugs. All compounds were found to be isomorphic and with tailorable antimicrobial activity according to the cation–anion combination against Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae strains.

The aim of this work is to develop an optimized enzymatic assisted extraction methodology to extract carotenoids and phenolic compounds from sunflower wastes (petals and florets) using natural hydrophobic green solvents. Several natural green hydrophobic solvents were used as well as natural hydrophobic eutectic solvents composed of d,l-menthol and different acids, with different hydrophobicity. The multi-enzyme complex Viscozyme(®) was used to disrupt the cell wall of petals and disc florets. The extracted carotenoids content into the hydrophobic phase was quantified using UV–Vis spectrophotometry and the carotenoids profile was studied using high-performance liquid and thin layer chromatography. The amount of total sugars in the aqueous phase was also analyzed using the dinitrosalicylic acid (DNS) method to infer about the enzymatic action in cell wall. Phenolic compounds also in the aqueous phase were analyzed by Folin Denis method. The eutectic solvent d,l-menthol:d,l-lactic acid (M:HLac) (1:2) was the best solvent for extraction of carotenoids from sunflower wastes, with 147 ppm of carotenoids extracted, in comparison to 115 ppm obtained with the standard solvent, n-hexane. In what concerns phenolic compounds, M:HLac was again better than the standard solvent. The use of the multi-enzyme complex Viscozyme(®) had different responses, depending on the solvent tested. For the green solvent M:HLac, the enzyme improved the carotenoids extraction, achieving 335 ppm of carotenoids in the extract. The role of enzyme, solvent, water and sunflower quantity in the carotenoid extraction was evaluated and optimized through a central composite rotatable design (CCRD), using the M:HLac as solvent. According to the analysis of CCRD, the most efficient extractions were carried out using more solvent and less raw material, whose best result reached 1449 mg carotenoids/100 g biomass ppm of carotenoids. This work emphasizes the possibility of developing more sustainable enzyme-assisted separation processes, through the substitution of toxic solvents with natural, environmentally friendly, solvents.

In this contribution, thin poly(ionic liquid) (PIL) coatings with a well-defined pore structure built up from interpolyelectrolyte complexation between a PIL and poly(acrylic acid) (PAA) were successfully used for enhanced solid phase microextraction (SPME). The introduction of porosity with tunable polarity through the highly versatile PIL chemistry clearly boosts the potential of SPME in the detection of compounds at rather low concentrations. This work will inspire researchers to further explore the potential of porous poly(ionic liquid) materials in sensing and separation applications.

The introduction of ionic liquids (ILs), either as phase forming components or as adjuvants, in the implementation of aqueous biphasic systems (ABS) enabled to finely tune the properties of the two aqueous phases in equilibrium thus providing the opportunity to increase extraction efficiencies and selectivities of biomolecules. Nevertheless, the effect of ILs addition on the phase diagram behavior and partitioning of biomolecules changes depending on the polymer, salt, ILs and biomolecules used and is still not fully understood. In this context, the influence of the addition of 7 different ILs based on imidazolium, pyrrolidinium or pyrydinium cation on PEG 3350 + ammonium sulfate ((NH4)2SO4) ABS at 25 °C is studied in this work. In terms of phase equilibrium, it was observed that the chemical nature of the IL leads to either a decrease or increase of two-phase region, therefore in the latter affording a decrease in concentrations of phase forming compounds needed for the liquid-liquid demixing. It is shown, that the IL anion affinity for water or the anion’s hydrogen-bond basicity controls the phase splitting behavior and thus [C4mim][N(CN)2] is able to greatly enhance two-phase region. Moreover, these PEG 3350 + (NH4)2SO4 + IL ABS were tested in the extraction/concentration of myoglobin from aqueous solutions. The obtained results indicate that the myoglobin partition is strongly influenced by its hydrophilicity and pH of the phases in equilibrium. Consequently, it preferentially partitions to the salt-rich phase. However, partitioning studies in presence of ILs as adjuvants show that these compounds can tune the polarity of the PEG-rich phase thus offering a tunable platform for the purification of myoglobin. This ability greatly depends on the chemical structure of the IL used and closely follows the IL hydrogen-bond basicity (β), enabling the most hydrophilic IL – [C4mim][CH3CO2] – to change the myoglobin partitioning behavior from salt-rich to the PEG-rich phase.

Simple mixtures of ionic liquids (IL-IL mixtures) can become a promising approach for the substitution of task-specific ILs. Such a concept was explored in this article by comparison of the thermophysical properties of neat 1-ethyl-3-methylimidazolium 2,2,2-trifluoromethylsulfonyl-N-cyanoamide, [C2mim][TFSAM], and equimolar mixtures of two structurally similar ILs having more common ions. Molecular dynamics (MD) simulations were additionally used to further highlight structural aspects of these systems at a molecular level.

Unformatted postprint Clean and sustainable energy production has become a key global issue concerning the world’s energy shortage and environmental problematic. Despite the recognized potential of biohydrogen (bioH2) for sustainable development, there are still issues regarding its production and purification, such as the elimination of CO2, N2, and other impurities (H2O and H2S), so that an enriched H2 stream can be obtained for efficient energy generation. The use of poly(ionic liquid)s (PILs) and their derived composite materials incorporating ionic liquids (PIL–IL) has been considered as a highly promising strategy to design membranes with improved CO2 separation. In this study, membranes of pyrrolidinium-based PILs containing symmetric or asymmetric fluorosulfonyl derived anions, namely bis(fluorosulfonyl)amide ([FSI]–), (trifluoromethyl)sulfonyl-N-cyanoamide ([TFSAM]–) and (trifluoromethyl)sulfonyl-N-trifluoroacetamide ([TSAC]–), were prepared by the incorporation of different amounts of structurally similar ILs. The PIL–IL membranes were characterized by different techniques (TGA, DSC, FT-IR and Raman) and their CO2/H2 and H2/N2 separation performances were investigated. Higher CO2/H2 selectivities were obtained for PIL FSI–40 [C2mim][FSI] (αCO2/H2 = 9.0) and PIL TFSAM–40 [C2mim][TFSAM] (αCO2/H2 = 7.1) compared to those of PIL–IL membranes containing the conventional [TFSI]– anion at similar or even higher amounts of IL’s incorporation. Andreia S. L. Gouveia is grateful to FCT (Fundação para a Ciência e a Tecnologia) for her Doctoral (SFRH/BD/116600/2016) research grant. Liliana C. Tomé has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734. This work was supported by FCT through the project PTDC/CTM-POL/2676/2014. Centro de Química Estrutural acknowledges the financial support of Fundação para a Ciência e Tecnologia (UIDB/00100/2020). Elemental analysis and Raman spectroscopy were performed with the financial support from Ministry of Science and Higher Education of the Russian Federation using the equipment of Center for molecular composition studies of INEOS RAS.

Proteins display an essential role in numerous natural systems due to their structural and biological properties. Given their unique properties, proteins have been thoroughly investigated in the last few decades, offering a myriad of solutions for the development of innovative biomaterials, including films, foams, composites and gels, in particular for biomedical applications such as drug delivery systems, biosensors and scaffolds for tissue regeneration. In this context, this review intends to give a general overview of the potential of protein based materials within the sustainable polymers context, covering aspects ranging from protein types, selection/isolation to properties of protein based (nano) materials and biomedical applications, passing through preparation methodologies of materials.

In this work, extractive desulfurization of model fuel containing dibenzothiophene (DBT) and thiophene (Th) as sulfur compounds was carried out using 16 different Deep Eutectic Solvents (DES) based on polyethylene glycol (PEG) and its precursors. The aim of this study is the reduction of the sulfur content of fuels below the environmental regulation (10 ppm), using PEG-based DES as low-cost extraction media under mild conditions and to compare their extractive performance with that of PEG alone, which by itself is a green solvent. For that purpose, 7 different quaternary ammonium and phosphonium salts were combined with four different molecular weight grades of PEG and PEG precursors such as ethylene glycol and triethylene glycol. The best results were obtained for the DES composed of tetrabutylammonium chloride (TBAC) and PEG400, which showed that it is possible to achieve, in single extraction step, 85% and 68% of extraction efficiency, and deep desulfurization in 2 and 3 cycles, for DBT and Th, respectively. In addition, this DES is not soluble in the model fuel and its extraction capacity is independent on the starting sulfur concentration. Finally, after being reused six times, TBAC:PEG400 DES still maintained 53% and 17% of its capacity, for DBT and Th removal, respectively, and after a regeneration step the performance of the DES was fully recovered.

In this work, poly(ionic liquid)–ionic liquid (PIL–IL) composite membranes were prepared using the solvent casting technique. The studied PILs have pyrrolidinium polycation backbone ([Pyr11]+), while the five ILs display either an imidazolium ([C2mim]+) or a pyrrolidinium ([Pyr14]+) based cation. Both the PIL and IL components comprised cyano-functionalized anions ([N(CN)2]–, [C(CN)3]– or [B(CN)4]–), being the anion for each component different from one another. The use of the [NTf2]– anion was also tested for comparison. Several experimental conditions for the solvent casting procedure were tested in order to prepare homogenous and free standing PIL–IL composite membranes. The CO2 and N2 permeation properties (permeability, diffusivity and solubility) were evaluated at a fixed temperature (293 K) and constant trans-membrane pressure differential (100 kPa) using a time-lag apparatus, so that trends regarding the different anions either on the PIL or IL could be obtained and evaluated. From all 42 PIL–IL combinations tested, 21 were suitable membranes (homogeneous and free standing) for gas permeation experiments and 4 of them were on top or surpassed the 2008 Robeson upper bound for CO2/N2 separation. The best performance membranes contain the [C(CN)3]– and [B(CN)4]– anions, enlightening therefore the promise these anions entail for future high performance membranes for post-combustion CO2 separation.

Homogeneous, glossy and transparent nanocomposite films composed of pullulan (PL) and lysozyme nanofibers (LNFs) were developed by simple solvent casting from aqueous suspensions. The incorporation of LNFs into the PL matrix maintained the filmogenic ability of PL and endowed the nanocomposite films with good mechanical properties (Young's modulus = 1.91–2.50 GPa) and several functionalities, confirming the potential of LNFs as bioactive reinforcing elements for nanocomposites. The set of pliable films exhibits thermal stability up to 225 °C and maximum antioxidant activity around 77% (DPPH scavenging activity) for the film with the highest LNFs content (15.0 wt%). The antibacterial activity of the ensuing nanocomposite films towards Staphylococcus aureus, viz. lysozyme-resistant bacteria, was assessed, and the data show augmented antibacterial effectiveness with increasing content of nanofibers. These promising results show the potential of PL/LNFs nanocomposites as eco-friendly edible films for active packaging.

M13 is a filamentous, non-lytic bacteriophage that infects Escherichia coli via the F pilus. Currently, phage M13 is widely used in phage display technology and bio-nanotechnology, and is considered a possible antibacterial therapeutic agent, among other applications. Conventional phage purification involves 5-7 operational steps, with high operational costs and significant product loss (approximately 60%). In this work, we propose a scalable purification process for M13 bacteriophage using a novel stationary phase based on a polymeric ionic liquid (PIL) with a positively charged backbone structure. Poly (1-vinyl-3-ethyl imidazolium bis(trifluoromethylsulfonyl) imide) - poly(VEIM-TFSI) predominantly acted as an anion exchanger under binding-elution mode. This revealed to be a rapid and simple method for the recovery of phage M13 with an overall separation yield of over 70% after a single downstream step. To the best of our knowledge, PILs have never been used as separation matrices for biological products and the results obtained, together with the large number of cations and anions available to prepare PILs, illustrate well the large potential of the proposed methodology.

Deep eutectic solvents (DESs) constitute a new class of ionic solvents that has been developing at a fast pace in recent years. Since these solvents are commonly suggested as green alternatives to organic solvents, it is important to understand their physical properties. In particular, polarity plays an important role in solvation phenomena. In this work, the polarity of different families of DESs was studied through solvatochromic responses of UV-vis absorption probes. Kamlet-Taft α, β, π* and ETN parameters were evaluated using different solvatochromic probes, as 2,6-dichloro-4-(2,4,6-triphenyl-N-pyridino)-phenolate (Reichardt's betaine dye 33), 4-nitroaniline, and N,N-diethyl-4-nitroaniline for several families of DESs based on cholinium chloride, dl-menthol and a quaternary ammonium salt ([N4444]Cl). In addition, a study to understand the difference in polarity properties between DESs and the corresponding ILs, namely ILs based on cholinium cation and carboxylic acids as anions ([Ch][Lev], [Ch][Gly] and [Ch][Mal]), was carried out. The chemical structure of the hydrogen bond acceptor (HBA) in a DES clearly controls the dipolarity/polarizability afforded by the DES. Moreover, Kamlet-Taft parameters do not vary much within the family, but they differ among families based on different HBA, either for DESs containing salts ([Ch]Cl or [N4444]Cl) or neutral compounds (dl-menthol). A substitution of the HBD was also found to play an important role in solvatochromic probe behaviour for all the studied systems.

A supramolecular hydrogel based on a metal-containing deep eutectic solvent (DES) is presented here for the first time. The phase diagram of the DES-based hydrogel was drawn and its rheological properties were determined.

This work explores the preparation of ionic liquid (IL)-based semi-interpenetrating polymer network (sIPN) membranes composed of poly(ethylene oxide) (PEO) network and linear nitrile butadiene rubber (NBR), incorporating up to 66 wt% of three ILs with a common cation ([C2mim]+) and different anions ([C(CN)3]–, [NTf2]– and [FSI]–). All sIPN/IL membranes were characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and puncture tests. Ideal CO2/N2 and CO2/H2 separation performances of the prepared sIPN/IL membranes were investigated at T = 20 ◦C and 35 ◦C, respectively, and 1 bar of feed pressure. The incorporation of both [C2mim][NTf2] and [C2mim][FSI] ILs allowed to obtain sIPN/IL membranes with higher IL contents (66 wt%) compared to previously reported PIL–IL membranes with similar IL structures (40 wt %). The membranes containing [NTf2]– and [C(CN)3]– anions showed improved thermal stability compared to the neat PEO/NBR sIPN, being thermally stable up to 300 ◦C. Although sIPN/IL membrane mechanical properties were affected by the incorporation of IL, all membranes revealed high elongation properties (elongation upon puncture = 68–170%), mainly due to the presence of NBR component in the sIPN structure. The highest CO2/N2 permselectivity was obtained for the sIPN/66 wt% [C2mim][C(CN)3] membrane, while the sIPN/66 wt% [C2mim][FSI] membrane revealed the highest CO2 and N2 permeabilities. The incorporation of 66 wt% of [C2mim][FSI] into the sIPN also showed superior CO2/H2 separation performance, with a CO2 permeability of 727 Barrer and a CO2/H2 permselectivity of 10.9 info:eu-repo/semantics/publishedVersion

Deep Eutectic Solvents (DESs) have recently emerged as green alternatives to ionic liquids (ILs). Encouraged by the sustainability of this novel class of solvents, the aim of this work is to prepare DESs using three different hydrogen bond acceptors (HBA), such as cholinium chloride, acetylcholinium chloride and benzyldimethyl(2-hydroxyethyl)ammonium chloride and five naturally occurring carbohydrates, namely d -(+)-Xylose, d -(+)-Mannose, d -(−)-Fructose, d -(+)-Glucose and d -(−)-Ribose, which will act as hydrogen bond donors (HBD). NMR and FTIR were used to ascertain about the chemical structures and purities of these carbohydrates-based DESs, while their thermal properties were evaluated through DSC and TGA analysis. Due to the high viscosity of the carbohydrate-based DESs, and its high hydrophilic and hygroscopic nature, 10 wt% of water was added to mimic its use under normal atmosphere conditions and enable their use as solvents. Densities and viscosities at atmospheric pressure and in the temperature range between 293.15 K and 353.15 K were measured for the prepared DES aqueous solutions. Finally, the suitability of these carbohydrates-based DESs as solvents for the dissolution of rice straw was investigated.

Wastewater treatment plants do not properly address the removal of emerging micropollutants, such as pesticides, and thus these compounds contaminate water sources of public drinking water systems. In this context, this work focuses on the development of hydrophobic deep eutectic solvents (DESs), as cheap extractants for the removal of four neonicotinoids, Imidacloprid, Acetamiprid, Nitenpyram and Thiamethoxam, from diluted aqueous solutions. In particular, two different families of DESs, one based on natural neutral ingredients (DL-Menthol and natural organic acids) and the other based on quaternary ammonium salts and organic acids were prepared and their water stability carefully studied through 1H NMR. Only the chemically stable DESs were selected to be used as solvents in the extraction of the four neonicotinoids so that no contamination of the water cycle is attained, while reuse of the DES is possible. The final results were compared with those obtained for liquid-liquid extraction using hydrophobic imidazolium-based ionic liquids as solvents.

Immobilization of ionic liquids (ILs) into 3D metal–organic frameworks (MOFs) is reported. The incorporation of these composites in a polyimide-based matrix (Matrimid® 5218) to yield [IL@MOF]@Matrimid® 5218 is an efficient strategy to improve the permeability and selectivity toward CO2/N2 mixtures, presenting also a remarkable improvement in membrane flexibility and mechanical resistance. Using MOF-5, a crystalline phase different to its original phase is obtained after the incorporation of hydrated IL without loss of adsorptive properties.

The present study explores the preparation of dual nanofibrillar-based bio-sorbent films composed of cellulose nanofibrils (CNFs) and lysozyme nanofibrils (LNFs) for application in the removal of Hg(II) from aqueous solutions. The free-standing films were fabricated via simple vacuum filtration of water suspensions of CNFs and LNFs and disclose good mechanical and thermal properties. The Hg(II) removal efficiency was evaluated by atomic fluorescence spectroscopy in ultra-pure and natural spring waters contaminated with environmental realistic levels of mercury (50 μg L−1). The removal efficiency is pH-dependent reaching a maximum of 99 % after 24 h at a pH value close to the isoelectric point of the protein. Under the experimental conditions, the sorption kinetics are well described by the pseudo-second-order and Elovich models, suggesting a chemisorption mechanism. These results demonstrate the ability of the dual nanofibrillar-based films to remove Hg(II) from water samples reaching a residual concentration lower than the guideline value for water intended for human consumption (1 μg L−1). Therefore, the CNFs/LNFs bio-sorbents might be a solution to treat low-concentrated mercury-contaminated waters.

During the last years, poly(ionic liquids) (PILs) have been gaining increased attention as materials for analytical chemistry. This success is due to the fact that PILs synthesis is generally based on the polymerization of ionic liquid monomers (ILMs), and thus some of their remarkable properties are shared with their polymeric form. Consequently, the facile design of task-specific ILMs led to an important platform to design new materials for solid phase microextraction (SPME). In this review, a critical evaluation of the main breakthroughs on the use of PILs as extraction phases for SPME. In particular, this critical review covers from ILMs/PILs synthesis, fiber coating processes, surface modifications (silica and metallic supports), to extraction modes, analytes categories, type of equipment ending with a discussion on limitations and future perspectives. PILs are undoubtedly competing in the frontline as inspiring materials for SPME.

Non-steroidal anti-inflammatory drugs (NSAIDs) are largely consumed worldwide. As a result, NSAIDs were already found in a variety of environmental aqueous samples, in concentrations ranging from ng/L to µg/L. This is due to the inability of the currently used technologies in sewage treatment plants (STPs) and wastewater treatment plants (WWTPs) to completely remove such pollutants/contaminants, thus leading to serious environmental and public health concerns. This work addresses the preparation and application of materials based on silica chemically modified with ionic liquids (SILs) as alternative adsorbents to remove NSAIDs from aqueous media. Modified silica-based materials comprising the 1-methyl-3-propylimidazolium cation combined with six anions were prepared, and chemically and morphologically characterized. Adsorption kinetics, diffusion models and isotherms of sodium diclofenac – as one of the most worldwide consumed NSAIDs – were determined at 298 K. The Boyd’s film diffusion and Webber’s pore diffusion models were used to disclose the rate controlling step affecting the adsorption process. A maximum equilibrium concentration of sodium diclofenac of 0.74 mmol (0.235 g) per g of adsorbent was obtained. Several solvents were tested to remove diclofenac and to regenerate SILs, being the mixture composed of 1-butanol and water (85:15, v:v) identified as the most promising and eco-friendly. After 3 regeneration steps, the material is able to keep up to 75% of its initial adsorption efficiency. Considering the maximum values reported for sodium diclofenac in effluents from WWTPs/STPs, 1 g of the most efficient material is “ideally” able to treat ca. 50,000 L of water. These materials can thus be envisioned as efficient filters to be implemented at domestic environment in countries where the levels of pharmaceuticals are particularly high in drinking water.

The impact of fossil fuels impurities on outdoor air pollution is today a matter of great concern, with the transportation sector playing a major role. Given global efforts to reduce sulfur oxides emissions, and the increasingly tighter legislations, removal of sulfur contaminants liquid highway fuels is a pressing issue worldwide. The purpose of this review is to provide a detailed state of the art review concerning the use of deep eutectic solvents (DES) in the removal of sulfur pollutants from transportation fuels. Furthermore, a comparative evaluation regarding the use of these solvents versus Ionic Liquids (ILs) is also provided, taking into account several aspects, such as, evolution of technologies, solvents composition, extraction efficiencies and environmental and economic considerations. The large gap in terms of efficiency of the reported technologies, either using ILs or DES, between simulated matrices and real fuels is also discussed, highlighting the importance of academia and industry hand in hand work.

Aqueous biphasic systems based on ionic liquids (ILs) have been researched as promising extraction and purification routes for a huge diversity of compounds. The inherent tunability offered by ILs combined with the large variety of salts available underlines the reliable phase equilibrium data. In this vein, this work presents novel aqueous biphasic systems based on the 1-butyl-1-methylpyrrolidinium cation combined with anions derived from organic acids, such as acetate, trifluoroacetate, hexanoate, adipate, and one halogenated anion, bromide, in the presence of a powerful salting out species, the inorganic salt K3PO4. The capacity of these ILs to undergo phase separation is discussed in regard to the chemical structure of the IL anion. The results here obtained were compared with those determined for poly(ionic liquid) analogues, and it was observed that while in ILs the hydrophobicity of the anion has the major role in phase splitting, in poly(ionic liquid)s that role is played by the polymer molecular ...

This work explores ionic liquid-based membranes with siloxane functionalized cations using two different approaches: supported ionic liquid membranes (SILMs) and poly(ionic liquid)–ionic liquid (PIL–IL) composite membranes. Their CO2, CH4, and N2 permeation properties were measured at T = 293 K with a trans-membrane pressure differential of 100 kPa. The thermophysical properties of the synthesized siloxane-functionalized ILs, namely viscosity and density (data in the Supporting Information), were also determined. Contrary to what was expected, the gas permeation results show that the SILMs containing siloxane-functionalized cations have CO2 permeabilities that are lower than those of their analogues without the siloxane functionality. The addition of siloxane-based ILs into PILs increases both CO2 permeability and CO2/N2 permselectivity, although it does not significantly change the CO2/CH4 permselectivity. The prepared membranes present very diverse CO2 permeabilities, between 57 and 568 Barrer, while they show permselectivities varying from 16.8 to 36.8 for CO2/N2 and from 9.8 to 11.5 for CO2/CH4. As observed for other ILs, superior CO2 separation performances were obtained when the IL containing [C(CN)3]− is used compared to that having the [NTf2]− anion.

Fundacao para a Ciencia e a Tecnologia through project (PEst-C/LA0006/2013). The authors also thank Prof. Madalena Dionisio and Dr Natalia Correia for their support with the DSC analyses. Herein a straightforward approach for the enhancement of the water solubility of common antibiotic and NSAID active pharmaceutical ingredients (APIs) is presented. The APIs are converted into ionic liquids (API-ILs) and molten salts by combination with the organic superbases TMG, DBU and DBN. The prepared superionic liquids were characterized by 1H and 13C NMR as well as FTIR spectroscopy and elemental analysis. Most products are amorphous non-polymorphic room temperature ionic liquids with very high solubility in water, which may enhance the bioavailability of the API-ILs in comparison with the parent drugs. authorsversion published

The CO2 and N2 permeation properties of ionic liquids (ILs) based on the 1-ethyl-3-methylimidazolium cation ([C2mim]+) and different fluorinated anions, namely 2,2,2-trifluoromethylsulfonyl-N-cyanoamide ([TFSAM]-), bis(fluorosulfonyl) imide ([FSI]-), nonafluorobutanesulfonate ([C4F9SO3]-), tris(pentafluoroethyl)trifluorophosphate ([FAP]-), and bis(pentafluoroethylsulfonyl)imide ([BETI]-) anions, were measured using supported ionic liquid membranes (SILMs). The results show that pure ILs containing [TFSAM]- and [FSI]- anions present the highest CO2 permeabilities, 753 and 843 Barrer, as well as the greatest CO2/N2 permselectivities of 43.9 and 46.1, respectively, with CO2/N2 separation performances on top of or above the Robeson 2008 upper bound. The re-design of the [TFSAM]- anion by structural unfolding was investigated through the use of IL mixtures. The gas transport and CO2/N2 separation properties through a pure [C2mim][TFSAM] SILM are compared to those of two different binary IL mixtures containing fluorinated and cyano-functionalized groups in the anions. Although the use of IL mixtures is a promising strategy to tailor gas permeation through SILMs, the pure [C2mim][TFSAM] SILM displays higher CO2 permeability, diffusivity and solubility than the selected IL mixtures. Nevertheless, both the prepared mixtures present CO2 separation performances that are on top of or above the Robeson plot.

To advance the ionic liquid (IL) platform to tailor fluorinated surfactant properties, the aim of this work is to evaluate the surfactant properties of cholinium-based salts bearing perfluoroalkanoate anions. Novel surfactant ILs containing the cholinium cation [Ch]+ combined with different perfluoroalkanoate anions, namely perfluoropentanoate [PFPent]−, perfluorohexanoate [PFHex]−, perfluoroheptanoate [PFHept]−, and perfluorooctanoate [PFOct]−, were synthesized. The critical micelle concentrations (CMCs) were determined using an ionic conductivity method, at different temperatures. Thermodynamic parameters of micellization were also evaluated. The results indicate that the CMC value decreases in a linear manner with the increment of the fluoroalkyl chain length in the anion. The evaluation of the thermodynamic parameters shows that the micellization is spontaneous and entropically driven and that the enthalpy of micellization is very small. It was also observed that the introduction of the cholinium cati...