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1. Exploring the compositional space of a metal–organic framework with ionic liquids to develop porous ionic conductors for enhanced signal and selectivity in VOC capacitive sensors.

Author

Gonçalves, Bruna F., Fernández, Eduardo, Valverde, Ainara, Gaboardi, Mattia, Salazar, Hugo, Petrenko, Viktor, Porro, José María, Cavalcanti, Leide P., Urtiaga, Karmele, Esperança, José M. S. S., Correia, Daniela M., Fernandez-Alonso, Felix, Lanceros-Mendez, Senentxu, and Fernández de Luis, Roberto

Abstract

The monitoring of atmospheric pollutants, especially non-methane-based volatile organic compounds (NMVOCs), is an important paradigm towards secure air quality surroundings. However, existing gas sensing technologies face challenges in selectively and sensitively detecting individual NMVOCs due to their low concentration in comparison to the main atmospheric components. In this research, the compositional space between a Metal–Organic Framework (MOF) and Ionic Liquids (ILs) is explored to fine tune the signal and selectivity of a capacitive gas sensing layer. Firstly, by tuning the weight ratio of the MOF : IL components, ionic conductive materials ranging from solid porous to partially porous inks are produced. Secondly, by combining the sensitivity arising from the IL's dielectric characteristics with the selectivity endowed by the MOF's porosity, varied capacitive responses are obtained. Finally, the sensing responses of thirteen sensors towards the detection of water vapor, ethanol, acetone and isopropanol demonstrate that the hybridization of the MOF/IL offers a suitable avenue to balance the porosity, magnitude of response, and partial selectivity. In addition, when the responses of multiple MOF/IL sensors are evaluated, cross-selectivity detection of individual NMVOCs is reached. This approach contributes to fine-tuning the MOF/IL sensor performance not just by expanding the MOF/IL combinations, but optimizing sensor processing by advanced printing and electronics design. [ABSTRACT FROM AUTHOR]

Published
2024
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3. one-step extraction and separation of betalains and chlorophylls using thermoreversible aqueous biphasic systems

Author

Rosa, Marguerita E., Ferreira, Ana M., Neves, Catarina M. S. S., Almeida, Mafalda R., Barros, Rafael, Cristovão, Ana C., Sousa, Ana C. A., Reis, Patrícia M., Rebelo, Luís Paulo N., Esperança, José M. S. S., Coutinho, João A. P., Freire, Mara G., LAQV@REQUIMTE, and DQ - Departamento de Química

Subjects
Environmental Chemistry, SDG 8 - Decent Work and Economic Growth, SDG 12 - Responsible Consumption and Production, Pollution
Abstract

This work was partly developed within the scope of the projects CICECO-Aveiro Institute of Materials, LA/P/0006/2020 and the Associate Laboratory for Green Chemistry-LA/P/0008/2020, financed by national funds through the FCT/MCTES (PIDDAC). Publisher Copyright: © 2023 The Royal Society of Chemistry. Globally, up to 50% of root crops, fruits and vegetables produced is wasted. Beetroot stems and leaves fit into this scenario, with only a small fraction being used in cattle food. One way of approaching this problem is through their valorisation, by extracting and recovering valuable compounds present in this type of waste that could be used in other applications, while contributing towards a circular economy. In this work, a new integrated process using thermoreversible aqueous biphasic systems (ABS) composed of quaternary ammonium-based ionic liquids (ILs) and polypropyleneglycol 400 g mol−1 (PPG) is shown to allow the one-step extraction and separation of two pigment classes—betalains and chlorophylls—from red beet stems and leaves. The pigment extraction was carried out with a monophasic aqueous solution of the IL and PPG, whose phase separation was then achieved by a temperature switch, resulting in the simultaneous separation of chlorophylls and betalains into opposite phases. A central composite design was used to optimise the extraction parameters (time, temperature, and solid : liquid (S/L) ratio) of both pigment extraction yields, reaching at 20 °C, 70 min and a S/L ratio of 0.12 a maximum extraction yield of 6.67 wt% for betalains and 1.82 wt% for chlorophylls (per weight of biomass). Moreover, it is shown that aqueous solutions of ILs better stabilise betalains than the gold standard solvent used for the extraction method. Among the studied systems, the ABS comprising the IL N-ethyl-N-methyl-N,N-bis(2-hydroxyethyl) bromide ([N21(2OH)(2OH)]Br) presented the best separation performance, with an extraction efficiency of 92% and 95% for chlorophylls and betalains, respectively, for opposite phases. The pigments were removed from the respective phases using affinity resins, with high recoveries: 96% for betalains and 98% for chlorophylls, further allowing the IL reuse. Finally, the cyto- and ecotoxicities of the quaternary ammonium-based ILs were determined. The obtained results disclosed low to negligible toxicity in the thousands of mg L−1 range, with [N21(2OH)(2OH)]Br being harmless from an ecotoxicological point of view. Overall, it is shown here that the developed process is an innovative approach for the one-step extraction and selective separation of pigments contributing to the valorisation of waste biomass. publishersversion published

Published
2023

5. Valorisation of red beet waste: one-step extraction and separation of betalains and chlorophylls using thermoreversible aqueous biphasic systems

Author

Rosa, Marguerita E., primary, Ferreira, Ana M., additional, Neves, Catarina M. S. S., additional, Almeida, Mafalda R., additional, Barros, Rafael, additional, Cristovão, Ana C., additional, Sousa, Ana C. A., additional, Reis, Patrícia M., additional, Rebelo, Luís Paulo N., additional, Esperança, José M. S. S., additional, Coutinho, João A. P., additional, and Freire, Mara G., additional

Published
2023
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9. A Mini Review

Author

Altamash, Tausif, Esperança, José M. S. S., Tariq, Mohammad, DQ - Departamento de Química, and LAQV@REQUIMTE

Subjects
gas hydrates, hydrate adhesion, wettability, coatings, flow assurance, hydrate-phobic surfaces
Abstract

LA/P/0008/2020 Gas hydrates (GHs) are known to pose serious flow assurance challenges for the oil and gas industry. Neverthless, over the last few decades, gas hydrates-based technology has been explored for various energy- and environmentally related applications. For both applications, a controlled formation of GHs is desired. Management of hydrate formation by allowing them to form within the pipelines in a controlled form over their complete mitigation is preferred. Moreover, environmental, benign, non-chemical methods to accelerate the rate of hydrate formation are in demand. This review focused on the progress made in the last decade on the use of various surface coatings and treatments to control the hydrate formation at atmospheric pressure and in realistic conditions of high pressure. It can be inferred that both surface chemistry (hydrophobicity/hydrophilicity) and surface morphology play a significant role in deciding the hydrate adhesion on a given surface. publishersversion published

Published
2021

14. A Database of Selectivity at Infinite Dilution for Liquid-Liquid Extraction

Author

Klimenko, Kyrylo, Inês, João Miguel, Esperança, José M. S. S., Aires-De-Sousa, João, Carrera, Gonçalo V. S. M., LAQV@REQUIMTE, and DQ - Departamento de Química

Subjects
ionic liquids, Chemistry(all), green chemistry, liquid-liquid equilibrium, Chemical Engineering(all), azeotrope separation, Industrial and Manufacturing Engineering
Abstract

Funding Information: We thank Portuguese Foundation for Science and Technology Project: PTDC/EQU-EQU/30060/2017. This work was supported by the Associate Laboratory for Green Chemistry – LAQV which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020). One of the most acute health and environmental concerns nowadays is 3Rs (Reduce, Reuse, and Recycle) of organic solvents. The existing technology used for solvent separation is either expensive or inefficient, particularly in the case of azeotrope separation. Ionic liquids (ILs) have already shown potential in liquid-liquid extraction of organic solvents due to their high structural variability. However, which IL will be efficient in a particular separation task is not always known, and experimental screening for selective ILs can be expensive and time-consuming. The preferable alternative is to use selectivity at infinite dilution (S∞). In this study, the database for S∞ was developed by computationally processing activity coefficients at infinite dilution from free available sources. S∞ was compared to experimental values of selectivity where possible, and the results show that there is an ≈80% chance that a "selective"IL, according to S∞, will be selective in liquid-liquid extraction. The results were analyzed with respect to the chemical classes of azeotrope components, showing quite a difference in S∞ to selectivity translation. An example of structure-property analysis was given to illustrate the usefulness of the database for understanding the effects of the structure on S∞ and design of new ILs for breaking particular two-component systems. The SQL database is freely available online and can be used for the intelligent search for better liquid-liquid extractants. authorsversion published

Published
2021

16. Odd-even effect on the formation of aqueous biphasic systems formed by 1-alkyl-3-methylimidazolium chloride ionic liquids and salts.

Author

Belchior, Diana C. V., Sintra, Tânia E., Carvalho, Pedro J., Soromenho, Mário R. C., Esperança, José M. S. S., Ventura, Sónia P. M., Rogers, Robin D., Coutinho, João A. P., and Freire, Mara G.

Subjects
IONIC liquids, AQUEOUS solutions, ANALYTICAL chemistry, LIQUID-liquid interfaces, TERNARY system, METHYLENE group, IONIC conductivity measurement
Abstract

This work provides a comprehensive evaluation of the effect of the cation alkyl side chain length of the 1-alkyl-3-methylimidazolium chloride series ([CnC1im]Cl, n = 2-14) of ionic liquids (ILs) on their capability to form aqueous biphasic systems (ABSs) with salts and self-aggregation derived properties. The liquid-liquid phase behavior of ternary systems composed of [CnC1im]Cl, water, and K3PO4 or K2CO3 and the respective Setschenow salting-out coefficients (ks), a quantitative measure of the two-phase formation ability, were determined. An odd-even effect in the ks values along the number of methylene groups of the longest IL cation alkyl side chain was identified for the ABS formed by K2CO3, a weaker salting-out agent where the phenomenon is clearly identified. In general, cations with even alkyl side chains, being likely to display higher molar volumes, are more easily salted-out and thus more prone to undergo phase separation. The odd-even effect in the ks values is, however, more significant in ILs up to n = 6, where the nanostructuration/nanosegregation of ILs plays a less relevant role. Still, with the [CnC1im]Cl (n = 7-14) series of ILs, an odd-even effect was also identified in the ILs’ ionization degree, molar conductivity, and conductivity at infinite dilution. In summary, it is shown here that the ILs’ odd-even effect occurs in IL aqueous solutions and not just in neat ILs, an already well-established phenomenon occurring in a series of ILs’ properties described as a result of the orientation of the terminal methyl groups to the imidazolium ring cation and consequent effect in the ILs’ cohesive energy. [ABSTRACT FROM AUTHOR]

Published
2018
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18. New luminescent tetracoordinate boron complexes: an in-depth experimental and theoretical characterisation and their application in OLEDs

Author

Paramasivam, Krishnamoorthy, primary, Fialho, Carina B., additional, Cruz, Tiago F. C., additional, Rodrigues, Ana I., additional, Ferreira, Bruno, additional, Gomes, Clara S. B., additional, Vila-Viçosa, Diogo, additional, Charas, Ana, additional, Esperança, José M. S. S., additional, Vieira Ferreira, Luís F., additional, Calhorda, Maria José, additional, Maçanita, António L., additional, Morgado, Jorge, additional, and Gomes, Pedro T., additional

Published
2021
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19. Effect of Thiouronium-Based Ionic Liquids on the Formation and Growth of CO 2 (sI) and THF (sII) Hydrates.

Author

Soromenho, Mário R. C., Keba, Anastasiia, Esperança, José M. S. S., and Tariq, Mohammad

Subjects
IONIC liquids, CARBON dioxide, HYDRATES, ATMOSPHERIC pressure, CRYSTAL growth, PHASE equilibrium
Abstract

In this manuscript, two thiouronium-based ionic liquids (ILs), namely 2-ethylthiouronium bromide [C2th][Br] and 2-(hydroxyethyl)thiouronium bromide [C2OHth][Br], were tested at different concentrations (1 and 10 wt%) for their ability to affect CO2 (sI) and tetrahydrofuran (THF) (sII) hydrate formation and growth. Two different methods were selected to perform a thermodynamic and kinetic screening of the CO2 hydrates using a rocking cell apparatus: (i) an isochoric pressure search method to map the hydrate phase behavior and (ii) a constant ramping method to obtain the hydrate formation and dissociation onset temperatures. A THF hydrate crystal growth method was also used to determine the effectiveness of the ILs in altering the growth of type sII hydrates at atmospheric pressure. Hydrate–liquid–vapor equilibrium measurements revealed that both ILs act as thermodynamic inhibitors at 10 wt% and suppress the CO2 hydrate equilibria ~1.2 °C. The constant ramping methodology provides interesting results and reveals that [C2OHth][Br] suppresses the nucleation onset temperature and delays the decomposition onset temperatures of CO2 hydrates at 1 wt%, whereas suppression by [C2th][Br] was not statistically significant. Normalized pressure plots indicate that the presence of the ILs slowed down the growth as well as the decomposition rates of CO2 hydrates due to the lower quantity of hydrate formed in the presence of 1 wt% ILs. The ILs were also found to be effective in inhibiting the growth of type sII THF hydrates without affecting their morphology. Therefore, the studied thiouronium ILs can be used as potential dual-function hydrate inhibitors. This work also emphasizes the importance of the methods and conditions used to screen an additive for altering hydrate formation and growth. [ABSTRACT FROM AUTHOR]

Published
2022
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26. Simultaneous Separation of Antioxidants and Carbohydrates From Food Wastes Using Aqueous Biphasic Systems Formed by Cholinium-Derived Ionic Liquids

Author

Neves, Catarina M. S. S., primary, Figueiredo, Marcos, additional, Reis, Patrícia M., additional, Sousa, Ana C. A., additional, Cristóvão, Ana C., additional, Fiadeiro, Mariana B., additional, Rebelo, Luís Paulo N., additional, Coutinho, João A. P., additional, Esperança, José M. S. S., additional, and Freire, Mara G., additional

Published
2019
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