ITQB: MT - PhD Theses
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- A sustainable path towards water purification an insight based on hydrophobic Deep Eutectic SolventsPublication . Florindo, Catarina; Marrucho, Isabel; Branco, Luís"One of the main concerns of modern society is to provide clean water for everyone. The occurrence of a wide diversity of micropollutants in aquatic ecosystems leads to serious public health and environmental problems. Thus, the development of sustainable and cost-effective alternatives for water purification technologies is nowadays an important challenge. Deep eutectic solvents (DESs) have been proposed as new alternatives to conventional solvents and even ionic liquids. The choice of low cost, naturally occurring compounds and the straightforward preparation are among the key features of these solvents.(...)"
- Synthetic approach towards biomass derived pyridinium saltsPublication . Sowmiah, Subbiah; Rebelo, Luís Paulo; Afonso, Carlos; Esperança, José"This thesis entitled “Synthetic approach towards the biomass derived pyridinium salts” was developed with an aim to develop a sustainable methodology for the synthesis of pyridinium salts that possesses high synthetic value and exhibit potential biological activity along with various industrial applications and were discussed in each chapter wherever necessary.(...)"
- Development of new membranes based on ionic liquid materials for gas separationPublication . Tomé, Liliana Sofia Carvalho; Marrucho, IsabelIn the field of energy, natural gas is an essential bridge to a clean, low carbon, renewable energy era. However, natural gas processing and transportation regulation require the removal of contaminant compounds such as carbon dioxide (CO2). Regarding clean air, the increasing atmospheric concentrations of greenhouse gases, specifically CO2, is of particular concern. Therefore, new costeffective, high performance technologies for carbon capture have been researched and the design of materials with the ability to efficiently separate CO2 from other gases is of vital importance.(...)
- Creating greater value for biomass residuesPublication . Ferreira, Rui Manuel Cordeiro; Rebelo, Luís Paulo; Pereira, Cristina SilvaRenewable resources have been the focus of both the scientific and industrial communities as substitutes for fossil fuels. Numerous studies have addressed the conversion of biomass to value-added chemicals, to materials, to fuels and into power and/or heat, i.e. biorefinery. The main goal of this thesis is to develop alternative extraction processes to isolate value-added constituents from biomass residues. Cork and birch outer bark were selected since the corresponding processing industries generate significant amounts of residues with high contents of value-added compounds, namely suberin (structural component) and triterpenes (extractable components).(...)
- Revealing fungal activity in the presence of ionic liquidsPublication . Petković, Marija; Rebelo, Luís Paulo N.; Pereira, Cristina SilvaIonic liquids constitute a vast and heterogeneous group of chemicals, generally non-volatile and of high solvent quality. They are already used in industrial processes; future applications depend heavily on conscious design of ionic liquids. Given especially the global demand for sustainable chemicals, understanding environmental risks is a priority, necessitating a multidisciplinary research approach, covering a broad range of disciplines from biology to chemistry. Ascomycota fungi are highly suitable model organisms, especially due to their environmental ubiquity and important role in the biotic decay of pollutants. This thesis reports the first ever use of Ascomycota fungi to investigate ionic liquids ecotoxicity and environmental persistence. Fungal strains of Penicillium and Aspergillus were in general found to be more tolerant to ionic liquids containing imidazolium, pyridinium, pyrrolidinium, cholinium or phosphonium cations, than any other microorganism tested to date (Chapters II, III and IV). The capacity of the strains to tolerate the ionic liquids tested was apparently correlated to their phylogeny. Ionic liquid toxicity was evaluated using common parameters, such as growth inhibition and death. Less frequently evaluated parameters were also analysed, including monitoring of the integrity of the cellular boundaries of fungal conidia by microscopy (Chapter IV) and determining the diffusible fungal metabolome by ESI-MS and LC (Chapter II and V). Overall, these data significantly contribute to current understanding of structure-activity relationships in ionic liquids. For example toxicity is apparently a function of alkyl chain length of both anion and cation (Chapters III and IV, respectively). A critical review of current understanding of toxicity and environmental impact of the principal ionic liquid groups made it clear that the common generalisation of ionic liquids being either “green” or “toxic”(...)
- Phase behaviour of alternative solventsPublication . Blešić, Marijana; Rebelo, Luís PauloThis Thesis is mainly focused on phase behaviour in macro and nano domains and thermodynamic properties of mixtures containing ionic liquids and water, fluorinated or organic solvents. A broad list of commercially available ionic liquids or specific and functionalised, synthesised and characterised by the author of the Thesis is included in this study. The used ionic liquids contained the following cations: 1-alkyl-3-methylimidazolium [Cnmim]+, 1-alkyl-3-methylpyridinium [Cnmpyr]+, 1- alkyl-1-methylpyrrolidinium [Cnmpyrr]+, 1-alkyl-1-methylpiperidinium [Cnmpip]+, and tetraalkylphosphonium [CxCyCzCwP]+ and some of the anions: chloride Cl-, Br-, hexafluorophosphate [PF6]-, bis{(trifluoromethyl)sulfonyl}amide [NTf2]-, alkylsulfonate [CmSO3]-, trifluoromethanesulfonate [OTf]-, dicyanamide [dca]- and acetate [Ac]-.(...)