Emerging Ionic Soft Materials based on Deep Eutectic Solvents

PostprintIn the last five years, the use of deep eutectic solvents (DES) have been opening new perspectives towards the creation of novel ionic soft materials as alternatives to expensive ionic liquids. This Mini-Review highlights the progress and advances in soft ionic materials or gels, mostly composed by a DES immobilized within difference matrices, such as linear polymers, polymer networks, biopolymers, supramolecular compounds or organosilane networks. By taking advantage of the DES characteristics and properties in the solid state, this building system delivers a variety of tailor-made materials showing different functionalities (ionic conductivity, self-healing, stretchability and pH-responsiveness) and offers a way to circumvent drawbacks related to shaping and risk of leakage in many technological applications. In this context, we provide a judicious analysis of these emerging ionic soft materials, their properties and applications open in energy, (bio)electronics, drug delivery, analytical chemistry, and wastewater treatment. Perspectives and opportunities for future research directions on this blossoming field are also discussed.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 Marie Sklodowska-Curie Research and Innovation Staff Exchanges (RISE) project under the grant agreement No 823989 “IONBIKE”

Imidazolium-based co-poly(ionic liquid) membranes for CO2/N2 separation

Unformatted post printThe development of efficient carbon dioxide capture and separation technologies is at the fore front of the priorities in the climate change policies. Poly(ionic liquid)s (PILs) have been emerging as extremely promising materials for the fabrication of membranes for CO2 separation. This work is a step forward to evaluate the performance of PIL-based copolymers in the preparation of membranes for CO2/N2 separation. In particular, imidazolium-based homo and copolymers were synthesized by RAFT co-polymerization of different imidazolium salts and characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) analysis. The membrane forming ability of the synthesized PILs, as well as the influence of different side chain groups (ethyl, pentyl, benzyl and napthyl) at imidazolium ring, were evaluated using the solvent casting technique. In order to improve membrane forming ability and CO2 separation performance, different amounts of free ionic liquid (IL), [C2mim][NTf2], were added into the synthesized homo and copolymers, and PIL–IL composite membranes were prepared. The CO2 and N2 permeation properties of the obtained free standing PIL–IL membranes were measured at 20 ºC and 100 kPa and the results obtained compared through the Robeson plot.K. Vijayakrishna and N. Pothanagandhi thank “International Research Staff Exchange Scheme (IRSES) 7th Framework of European Union People-2012-IRSES” (Project No: 318873), for exchange programme. K. Vijayakrishna also thank DST-SERB, India (Project NO: SR/S1/OC-22/2012) for the financial support. L.C. Tomé is grateful to FCT (Fundação para a Ciência e a Tecnologia) for her Post-doctoral research grant (SFRH/BPD/101793/2014). This work was supported by FCT through the project PTDC/CTM-POL/2676/2014 and R&D units UID/Multi/04551/2013 (GreenIT) and UID/QUI/00100/2013 (CQE). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734

Impact of MOF-5 on pyrrolidinium-based poly(ionic liquid)/ionic liquid membranes for biogas upgrading

PostprintBearing in mind that Metal Organic Frameworks (MOFs) have remarkable CO2 adsorption selectivity and Mixed Matrix Membranes (MMMs) have been identified as potential solution for advancing the current state of the art of membrane separation technology, this work investigates the effect of combining a MOF, with high adsorption properties towards CO2 when compared to CH4 (MOF-5), with a blend of poly(ionic liquid)/ionic liquid (PIL/IL) for biogas upgrading. The blend system consisted of a pyrrolidinium-based PIL, poly([Pyr11][Tf2N]), and a free imidazolium-based IL, [C2mim][BETI]. The MOF-5 was incorporated at different loadings (10, 20, 30 wt%), and MMMs were prepared by solvent evaporation technique and characterized by diverse techniques (FTIR, SEM, TGA, puncture tests, water contact angle and single gas transport). The results showed that the free IL is miscible with the PIL, while MOF-5 particles were uniformly dispersed into the PIL/IL matrix. The formed PIL/IL/MOF-5 membranes revealed suitable thermal stability (Tonset up to 656 K) for biogas upgrading processes, but a loss of mechanical stability was found after the incorporation of MOF-5, and thus more rigid and fragile membranes were obtained. Besides, increasing MOF-5 content in the MMMs resulted in improved CO2 permeability. At 30 wt% of MOF-5 loading the CO2 permeability increased 133% when compared to that of the pristine PIL/IL membrane, while the ideal selectivity CO2/CH4 decreases. It was possible to demonstrate the relevance of studying different components within the polymeric matrix in order to assess not only thermal, mechanical and chemical properties, but also gas transport response.This work was supported by FCT (Fundação para Ciência e a Tecnologia) through the project PTDC/CTM-POL/2676/2014 and the Associate Laboratory for Green Chemistry - LAQV (UID/QUI/50006/2019). Ana R. Nabais and Luísa A. Neves are grateful to FCT/MCTES for their PhD grant (SFRH/BD/136963/2018) and FCT Investigador Contract (IF/00505/2014), respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 745734

Poly(Ethylene glycol) diacrylate iongel membranes reinforced with nanoclays for co2 separation

Despite the fact that iongels are very attractive materials for gas separation membranes, they often show mechanical stability issues mainly due to the high ionic liquid (IL) content (≥60 wt%) needed to achieve high gas separation performances. This work investigates a strategy to improve the mechanical properties of iongel membranes, which consists in the incorporation of montmorillonite (MMT) nanoclay, from 0.2 to 7.5 wt%, into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) network containing 60 wt% of the IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][TFSI]). The iongels were prepared by a simple one-pot method using ultraviolet (UV) initiated polymerization of poly(ethylene glycol) diacrylate (PEGDA) and characterized by several techniques to assess their physico-chemical properties. The thermal stability of the iongels was influenced by the addition of higher MMT contents (>5 wt%). It was possible to improve both puncture strength and elongation at break with MMT contents up to 1 wt%. Furthermore, the highest ideal gas selectivities were achieved for iongels containing 0.5 wt% MMT, while the highest CO2 permeability was observed at 7.5 wt% MMT content, due to an increase in diffusivity. Remarkably, this strategy allowed for the preparation and gas permeation of self-standing iongel containing 80 wt% IL, which had not been possible up until now.publishersversionpublishe

Tailored CO2-philic Anionic Poly(ionic liquid) Composite Membranes: Synthesis, Characterization and Gas Transport Properties

Unformatted post printPolymeric membranes either containing, or built from, ionic liquids (ILs) are of great interest for enhanced CO2/light gas separation due to the stronger affinity of ILs toward quadrupolar CO2 molecules, and hence, high CO2 solubility selectivity. Herein, we report the development of a series of four novel anionic poly(IL)-IL composite membranes via a photopolymerization method for effective CO2 separation. Interestingly, these are the first examples of anionic poly(IL)-IL composite systems, in which the poly(IL) component has delocalized sulfonimide anions pendant from the polymer backbone with imidazolium cations as “free” counterions. Two types of photopolymerizable methacryloxy-based IL monomers (MILs) with highly delocalized anions (–SO2–N(-)–SO2–CF3 and –SO2–N(-)–SO2–C7H7) and mobile imidazolium ([C2mim]+) counter cations were successfully synthesized and photopolymerized with two distinct amounts of free IL containing the same structural cation ([C2mim][Tf2N]) and 20 wt% PEGDA crosslinker, to serve as a composite matrix. The structure-property relationships of the four newly developed anionic poly(IL)-IL composite membranes were extensively characterized by TGA, DSC, and XRD analysis. All of the newly developed anionic poly(IL)-IL composite membranes exhibited superior CO2/CH4 and CO2/N2 selectivities together with moderate CO2/H2 selectivity and reasonable CO2 permeabilities. The membrane with an optimal composition and polymer architecture (MIL-C7H7/PEGDA(20%)/IL(1eq.)) reaches the 2008 Robeson upper bound limit of CO2/CH4, due to the simultaneous improvement in permeability and selectivity (CO2 permeability ~ 20 barrer and αCO2/CH4 ~119). This study provides a promising strategy to explore the benefits of anionic poly(IL)-IL composites to separate CO2 from flue gas, natural gas, and syngas streams and open up new possibilities in the polymer membrane design with strong candidate materials for practical applications.Partial support for this work provided by the United States Department of Energy (DE-SC0020282) and NASA Marshall Space Flight Center (80NSSC19K1314), is gratefully acknowledged. 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

Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins

<p>Abstract</p> <p>Background</p> <p>In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in <it>meso</it>-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (<it>Enterococcus faecalis</it>) and of a Gram (-) bacterium (<it>Escherichia coli</it>). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.</p> <p>Results</p> <p>Bacterial suspension (10⁷CFU mL^-1) treated with different photosensitizers concentrations (0.5, 1.0 and 5.0 μM) were exposed to white light (40 W m^-2) for a total light dose of 64.8 J cm^-2. The most effective photosensitizers against both bacterial strains were the Tri-Py⁺-Me-PF and Tri-Py⁺-Me-CO₂Me at 5.0 μM with a light fluence of 64.8 J cm^-2, leading to > 7.0 log (> 99,999%) of photoinactivation. The tetracationic porphyrin also proved to be a good photosensitizer against both bacterial strains. Both di-cationic and the monocationic porphyrins were the least effective ones.</p> <p>Conclusion</p> <p>The number of positive charges, the charge distribution in the porphyrins' structure and the <it>meso</it>-substituent groups seem to have different effects on the photoinactivation of both bacteria. As the Tri-Py⁺-Me-PF porphyrin provides the highest log reduction using lower light doses, this photosensitizer can efficiently photoinactivate a large spectrum of environmental bacteria. The complete inactivation of both bacterial strains with low light fluence (40 W m^-2) means that the photodynamic approach can be applied to wastewater treatment under natural light conditions which makes this technology cheap and feasible in terms of the light source.</p

Poly(ionic liquid)–ionic liquid membranes with fluorosulfonyl derived anions: characterization and biohydrogen separation

Unformatted postprintClean 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

Expanding the Applicability of Poly(Ionic Liquids) in Solid Phase Microextraction: Pyrrolidinium Coatings

Crosslinked pyrrolidinium-based poly(ionic liquids) (Pyrr-PILs) were synthesized through a fast, simple, and solventless photopolymerization scheme, and tested as solid phase microextraction (SPME) sorbents. A series of Pyrr-PILs bearing three different alkyl side chain lengths with two, eight, and fourteen carbons was prepared, characterized, and homogeneously coated on a steel wire by using a very simple procedure. The resulting coatings showed a high thermal stability, with decomposition temperatures above 350 degrees C, excellent film stability, and lifetime of over 100 injections. The performance of these PIL-based SPME fibers was evaluated using a mixture of eleven organic compounds with different molar volumes and chemical functionalities (alcohols, ketones, and monoterpenes). The Pyrr-PIL fibers were obtained as dense film coatings, with 67 mu m thickness, with an overall sorption increase of 90% and 55% as compared to commercial fibers of Polyacrylate (85 mu m) (PA85) and Polydimethylsiloxane (7 mu m) (PDMS7) coatings, respectively. A urine sample doped with the sample mixture was used to study the matrix effect and establish relative recoveries, which ranged from 60.2% to 104.1%.David J. S. Patinha, and Liliana C. Tome are grateful to FCT (Fundacao para a Ciencia e a Tecnologia) for the PhD research grant SFRH/BD/97042/2013 and the Post-Doctoral research grant (SFRH/BPD/101793/2014), respectively. David J. S. Patinha also thanks the financial support from COST-Exil Project 1206. The NMR data was acquired at CERMAX (Centro de Ressonncia Magnetica Antnio Xavier) which is a member of the National NMR network. This work was partially supported by FCT through Research Unit GREEN-it " Bioresources for Sustainability" (UID/Multi/04551/2013) and the Associate Laboratory CICECO Aveiro Institute of materials (UID/CTM/50011/2013)

Poly(ionic liquid)-based engineered mixed matrix membranes for CO2/H2 separation

Unformatted preprintPoly(ionic liquid)s (PIL) have emerged as a class of versatile polyelectrolites, that can be used to prepare new materials able to achieve superior performances compared to conventional polymers. The combination of PILs with ionic liquids (ILs) may serve as a suitable matrix for the preparation of membranes for gas separation. In this work, mixed matrix membranes (MMMs) combining a pyrrolidinium-based PIL, an IL and three highly CO2-selective metal organic frameworks (MOFs) were prepared. The different MOFs (MIL-53, Cu3(BTC)2 and ZIF-8) were used as fillers, aiming to maximize the membranes performance towards the purification of syngas. The influence of different MOFs and loadings (0, 10, 20 and 30 wt.%) on the thermal and mechanical stabilities of the membranes and their performance in terms of CO2 permeability and CO2/H2 ideal selectivity was assessed. The compatibility between the materials was confirmed by SEM-EDS and FTIR spectroscopy. The prepared MMMs revealed to be thermally stable within the temperature range of the syngas stream, with a loss of mechanical stability upon the MOF incorporation. The increasing MOF content in the MMMs, resulted in an improvement of both CO2 permeability and CO2/H2 ideal selectivity. Among the three MOFs studied, membranes based on ZIF-8 showed the highest permeabilities (up to 97.2 barrer), while membranes based on MIL-53 showed the highest improvement in selectivity (up to 13.3). Remarkably, all permeation results surpass the upper bound limit for the CO2/H2 separation, showing the membranes potential for the desired gas separation.This work was partially supported by R&D Units UID/Multi/04551/2013 (Green-it), UID/QUI/00100/2013 (CQE), and the Associated Laboratory Research Unit for Green Chemistry, Technologies and Clean Processes, LAQV which is financed by national funds from FCT/MCTES(UID/QUI/50006/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). Ana R. Nabais, Luísa A. Neves and Liliana C. Tomé acknowledge FCT/MCTES for financial support through project PTDC/CTM-POL/2676/2014, FCT Investigator Contract IF/00505/2014 and Post-doctoral research grant SFRH/BDP/101793/2014, respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 745734

Overview of Membrane Science and Technology in Portugal

Funding Information: Acknowledgments: The authors acknowledge Tiago Araújo for his valuable contribution in writing—original draft preparation—the carbon molecular sieve membranes content. LCT is grateful to Fundação para a Ciência e a Tecnologia (FCT/MCTES) for her assistant researcher contract under Scientific Employment Stimulus (2020.01555.CEECIND). DMFS thanks FCT/MCTES for a research contract in the scope of programmatic funding UIDP/04540/2020. Funding Information: Funding: This work was supported by Associate Laboratory for Green Chemistry—LAQV, which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020), Research project PTDC/EQU-EPQ/29579/2017 funded by FCT/MCTES “Programa Operacional Regional de Lisboa, FEDER”, project Nanoart PTDC/CTM-BIO/6178/2014 and CeFEMA with grant number 325UID/CTM/04540/2013 funded by FCT/MCTES. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Membrane research in Portugal is aligned with global concerns and expectations for sustainable social development, thus progressively focusing on the use of natural resources and renewable energy. This review begins by addressing the pioneer work on membrane science and technology in Portugal by the research groups of Instituto Superior Técnico—Universidade de Lisboa (IST), NOVA School of Science and Technology—Universidade Nova de Lisboa (FCT NOVA) and Faculdade de Engenharia—Universidade do Porto (FEUP) aiming to provide an historical perspective on the topic. Then, an overview of the trends and challenges in membrane processes and materials, mostly in the last five years, involving Portuguese researchers, is presented as a contribution to a more sustainable water–energy–material–food nexus.publishersversionpublishe