The use of deep eutectic solvents (DESs) for the preparation of polymer membranes for environmental separation technologies is comprehensively reviewed. DESs have been divided into five categories based on the hydrogen bond donor (HBD) and acceptor (HBA) that are involved in the production of the DESs, and a wide range of DESs’ physicochemical characteristics, such as density, surface tension, viscosity, and melting temperature, are initially gathered. Furthermore, the most popular techniques for creating membranes have been demonstrated and discussed, with a focus on the non-solvent induced phase separation (NIPS) method. Additionally, a number of studies have been reported in which DESs were employed as pore formers, solvents, additives, or co-solvents, among other applications. The addition of DESs to the manufacturing process increased the presence of finger-like structures and macrovoids in the cross-section and, on numerous occasions, had a substantial impact on the overall porosity and pore size. Performance data were also gathered for membranes made for various separation technologies, such as ultrafiltration (UF) and nanofiltration (NF). Lastly, DESs provide various options for the functionalization of membranes, such as the creation of various liquid membrane types, with special focus on supported liquid membranes (SLMs) for decarbonization technologies, discussed in terms of permeability and selectivity of several gases, including CO₂, N₂, and CH₄.

Poly(ethylene terephthalate) (PET) waste accumulation poses significant environmental challenges due to its persistent nature and current management limitations. This study explores the effectiveness of imidazolium-based neoteric solvents [Emim][OAc] and [Bmim][OAc] as catalytic co-solvents in the glycolysis of PET with ethylene glycol (EG). Reaction thermal kinetics showed that both ionic liquids (ILs) significantly enhanced the depolymerization rate of PET compared to traditional methods. The use of [Emim][OAc] offered a lower activation energy of 88.69 kJ·mol⁻¹, thus making the process more energy-efficient. The contribution of key process parameters, including temperature (T), plastic-to-ionic liquid (P/IL) mass ratio, and plastic-to-solvent (P/S) mass ratio, were evaluated by means of a factorial analysis and optimized to achieve the maximum PET conversion for both neoteric solvents. The relevance sequence for both ionic liquids involved the linear factors T and P/S, followed by the interaction factors T×P/S and T×P/IL, with P/IL being the less significant parameter. The optimal conditions, with a predicted conversion of 100%, involved a temperature of 190 °C, with a P/IL of 1:1 and a P/S of 1:2.5, regardless of the IL used as the catalytic co-solvent.

The textile industry is positioned as one of the most significant contributors to waste generation but remains with low implementation of post-consumer recycling practices. In response to this challenge, this study focuses on the physicochemical recycling of cotton derived from textile waste aided by a protic ionic liquid, 1,5-diazabicyclo [4.3.0]non-5-ene acetate ([DBNH][OAc]), as a green alternative solvent for dissolving cotton and generating a dope, which is then transformed into a filament through the wet spinning technique. A dedicated setup was developed for the spinning process, and an experimental design based on a statistical factorial approach was applied to optimise the spinning conditions, as temperature, die diameter and velocity of extrusion. The mechanical properties of the filaments, including tenacity and elongation at break, were analysed to assess their performance. The statistical model facilitated the simultaneous optimisation of both responses—tenacity and elongation—resulting in the following optimal conditions: a temperature of 95 °C, a flow rate of 70 μL·min⁻¹, and an extrusion diameter of 0.4 mm. The results demonstrate that both the selected solvent and wet spinning are effective in producing filaments suitable for reuse in the textile industry. Remarkably, filaments derived from textile waste exhibited superior mechanical properties compared to those obtained from virgin white cotton.

Gas separation membranes enable technologies that use selective permeation to separate gas mixtures of interest, such as biogas or flue gas, thereby reducing greenhouse gas emissions