Repurposing Kraft black Liquor as Reductant for Enhanced Lithium-Ion Battery Leaching

The economic advantages of H2 SO4 make it the acid of choice for the hydrometallurgical treatment of waste lithium-ion batteries (LIBs). However, to facilitate the full dissolution of the higher valency metal oxides present in the cathode black mass, a suitable reducing agent is required. Herein, the application of industrial black liquor (BL) obtained from the Kraft pulping for papermaking is investigated as a renewable reducing agent for the enhanced leaching of transition metals from LIB powder with H2 SO4 . The addition of acidified BL to H2 SO4 significantly improved the leaching efficiency for a range of LIB cathode chemistries, with the strongest effect observed for manganese-rich active material. Focusing on NMC111 (LiMnx Coy Niz O2 ) material, a linear correlation between the BL concentration and the leaching yield of Mn was obtained, with the best overall leaching efficiencies being achieved for 2.0 mol L-1 H2 SO4 and 50 vol % of BL at 353 K. A quasi-total degradation of oxygenated and aromatic groups from the BL during NMC111 dissolution was observed after leaching, suggesting that these chemical groups are essential for LIB reduction. Finally, the leached transition metals could be easily recovered by pH adjustment and oxalic acid addition, closing the resource loop and fostering resource efficiency.

Evaluation of a battery of biotests to improve waste ecotoxicity assessment (HP 14), using incineration bottom ash as a case study

The assessment of waste ecotoxicity (hazardous property HP14 in the European Union) is fundamental for proper waste classification and safe application/disposal. Biotests are relevant for evaluating waste complex matrices, but their efficiency is crucial to encourage their adoption at the industrial level. This work aims at evaluating possibilities of improving the efficiency of a biotest battery previously suggested in the literature, regarding test selection, duration, and/or laboratory resources optimization. Fresh incineration bottom ash (IBA) was the case study. The test battery analysed included standard aquatic (bacteria, microalgae, macrophytes, daphnids, rotifers, fairy shrimp) and terrestrial (bacteria, plants, earthworms, collembolans) organisms. The assessment followed an Extended Limit Test design (three dilutions of eluate or solid IBA) and the Lowest Ineffective Dilution (LID-approach) for ecotoxicity classification. The results emphasize the importance of testing different species. It was also evidenced that tests with daphnids and earthworms may be shortened to 24 h; the miniaturization of tests is suitable as e.g. differential sensitivity of microalgae and macrophytes was captured with low variability; alternative testing kits can be used when methodological difficulties are found. Microalgae were more sensitive than macrophytes. Similar results were found for the Thamnotoxkit and daphnids test for eluates with natural pH, so the former may be used as an alternative. B. rapa was the most sensitive organism, suggesting that it may be tested as the only terrestrial plant species and that minimum test duration is appropriate. F. candida does not appear to add information to the battery. The differences in sensitivity of A. fischeri and E. fetida compared to the remaining species were not significant enough to exclude them from the battery. Thus, this work suggests a biotest battery to test IBA comprising aquatic tests - Aliivibrio fischeri, Raphidocelis subcapitata (miniaturised test), and Daphnia magna (24 h when clear deleterious effects are observed) or Thamnocephalus platyurus (toxkit) - and terrestrial tests - Arthrobacter globiformis, Brassica rapa (14 d), and Eisenia fetida (24 h). Testing waste with natural pH is also recommended. The Extended Limit Test design considering the LID-approach seems useful in waste testing, particularly for the industry, involving low effort, test material requirements, and few laboratory resources. The LID-approach allowed for differentiating ecotoxic from non-ecotoxic effects and captured different sensitivities between species. Ecotoxicological assessment of other waste may benefit from these recommendations, but caution should be taken given the properties of each waste type.

An integrated characterisation of incineration bottom ashes towards sustainable application: Physicochemical, ecotoxicological, and mechanical properties

Environmental protection is a central concern regarding municipal solid waste incineration bottom ash (IBA) management, but the assessment of waste Hazardous Property HP14 (ecotoxicity) is still under debate. Civil engineering applications may be a suitable management strategy. This work aimed at evaluating IBA regarding mechanical behaviour and environmental hazardous potential, including a biotest battery for ecotoxicity assessment (comprising miniaturised tests), to explore its potential for safe utilization. Physical, chemical, ecotoxicological (Aliivibrio fischeri, Raphidocelis subcapitata, Lemna minor, Daphnia magna, Lepidium sativum), and mechanical (one-dimensional compressibility, shear strength) analyses were performed. The low leaching for potentially toxic metals and ions complied with European Union (EU) limit values for non-hazardous waste landfills. No relevant ecotoxicological effects were found. The biotest battery seems suitable for ecotoxicological assessment in the aquatic ecosystem, providing wide information on waste impact on different trophic/functional levels and chemical uptake routes, simultaneously involving short-duration tests and reduced amounts of waste. IBA presented more compressibility than sand, but its mixture with sand (30%:70%) was closer to sand compressibility. IBA (lower stresses) and the mixture (higher stresses) showed slightly higher shear strength than sand. Overall, IBA presented the potential for valorisation as loose aggregates from an environmental and mechanical viewpoint in a circular economy framework.

The role of biomass elemental composition and ion-exchange in metal sorption by algae

The use of macroalgae, microalgae and cyanobacteria for metal sorption has been widely reported. Still, there are no studies allowing a direct comparison of the performance of these biomasses, especially while evaluating metal competition. The simultaneous sorption of Co²⁺, Cu²⁺, Ni²⁺ and Zn²⁺ present in a multi-elemental solution by six macroalgae, two microalgae and three cyanobacteria was evaluated. Brown macroalgae were shown to be the most promising biosorbent, with Undaria pinnatifida having a total metal sorption capacity of 0.6 mmol g^-1. Overall, macroalgae performed better than microalgae, followed by cyanobacteria. Carboxyl groups were identified as being the main functional groups involved in metal sorption, and all biomass samples were found to be selective to Cu²⁺. This was linked not only to its higher complexation constant value with relevant functional groups when compared to the remaining metals, but also the Irving-Williams series. The release of K⁺ and Ca²⁺ to the aqueous solution during the metal sorption was followed. The obtained results suggest they are readily exchanged with metals in the solution, indicating the occurrence of an ion-exchange mechanism in metal sorption by most biomass. Red macroalgae are an exception to the reported trends, suggesting that their metal sorption mechanism may differ from the other biomass types.

Cyanobacteria as Candidates to Support Mars Colonization: Growth and Biofertilization Potential Using Mars Regolith as a Resource

Cyanobacteria are indicated as organisms that can possibly support Mars colonization, contributing to the production of oxygen and other commodities therein. In this general context, the aim of this work was to evaluate the ability of three species of cyanobacteria (Anabaena cylindrica, Nostoc muscorum, and Arthrospira platensis) and a green microalga (Chlorella vulgaris) to grow using only the resources existing in Mars, i.e., water and Martian regolith stimulant (MGS-1), under an Earth-like atmosphere. A Martian regolith extract was produced and used as a culture medium to grow these species. Their growth was assessed during a period of 25 days, using optical density and fluorometric parameters. After this period, the possible contribution of end-of-life cyanobacteria/microalga as biofertilizing agents was also assessed, using the macrophyte Lemna minor as a vegetable model. Among the three species, N. muscorum showed the best growth performance when compared to the other species, while A. platensis and C. vulgaris were not able to thrive on Mars regolith extract. Therefore, N. muscorum should be the target of future studies not only due to their role in oxygen production but also due to their possible use as a food source, as many members of the Nostoc genus. Cyanobacteria and microalgae (A. platensis and C. vulgaris) showed good abilities as biofertilizing agents, i.e., they stimulated biomass (i.e., dry weight) production at levels comparable to the plants that grew on standard synthetic medium. The highest yield was reached with A. platensis, while the lowest was achieved using the media with N. muscorum. FTIR-ATR (Fourier transform infrared with attenuated total reflectance) spectroscopy showed that the differences between the plants grown on media with or without Martian regolith seem to be related mainly to polysaccharides.

Synthesis of Purine-Based Ionic Liquids and Their Applications

Bio-based ionic liquids (ILs) are being increasingly sought after, as they are more sustainable and eco-friendly. Purines are the most widely distributed, naturally occurring N-heterocycles, but their low water-solubility limits their application. In this work, four purines (theobromine, theophylline, xanthine, and uric acid) were combined with the cation tetrabutylammonium to synthesize bio-based ILs. The physico-chemical properties of the purine-based ILs were characterized, including their melting and decomposition temperatures and water-solubility. The ecotoxicity against the microalgae Raphidocelis subcapitata was also determined. The ILs show good thermal stability (>457 K) and an aqueous solubility enhancement ranging from 53- to 870-fold, in comparison to their respective purine percursors, unlocking new prospects for their application where aqueous solutions are demanded. The ecotoxicity of these ILs seems to be dominated by the cation, and it is similar to chloride-based IL, emphasizing that the use of natural anions does not necessarily translate to more benign ILs. The application of the novel ILs in the formation of aqueous biphasic systems (ABS), and as solubility enhancers, was also evaluated. The ILs were able to form ABS with sodium sulfate and tripotassium citrate salts. The development of thermoresponsive ABS, using sodium sulfate as a salting-out agent, was accomplished, with the ILs having different thermosensitivities. In addition, the purine-based ILs acted as solubility enhancers of ferulic acid in aqueous solution.

A HNO3 -Responsive Aqueous Biphasic System for Metal Separation: Application towards CeIV Recovery

An acidic aqueous biphasic system (AcABS) presenting a desired and reversible phase transition with HNO₃ concentration and temperature was developed herein as an integrated platform for metal separation. The simple, economical, and fully incinerable (C,H,O,N) AcABS composed of tetrabutylammonium nitrate ([N₄₄₄₄ ][NO₃ ])+HNO₃ +H₂ O was characterized and presented an excellent selectivity towards Ce^IV against other rare earth elements and transition metals from both synthetic solutions and nickel metal hydride (NiMH) battery leachates. The acid-driven self-assembly of AcABS bridges the gap between traditional ABS and liquid-liquid extraction whilst retaining their advantageous qualities, including compatibility with highly acidic solutions, water as the primary system component, the avoidance of organic diluents, rapid mass transfer, and the potential integration of the leaching and separation steps.

Integrated Leaching and Separation of Metals Using Mixtures of Organic Acids and Ionic Liquids

In this work, the aqueous phase diagram for the mixture of the hydrophilic tributyltetradecyl phosphonium ([P44414]Cl) ionic liquid with acetic acid (CH3COOH) is determined, and the temperature dependency of the biphasic region established. Molecular dynamic simulations of the [P44414]Cl + CH3COOH + H2O system indicate that the occurrence of a closed "type 0" biphasic regime is due to a "washing-out" phenomenon upon addition of water, resulting in solvophobic segregation of the [P44414]Cl. The solubility of various metal oxides in the anhydrous [P44414]Cl + CH3COOH system was determined, with the system presenting a good selectivity for CoO. Integration of the separation step was demonstrated through the addition of water, yielding a biphasic regime. Finally, the [P44414]Cl + CH3COOH system was applied to the treatment of real waste, NiMH battery black mass, being shown that it allows an efficient separation of Co(II) from Ni(II), Fe(III) and the lanthanides in a single leaching and separation step.

Mechanisms of phase separation in temperature-responsive acidic aqueous biphasic systems

The thermal and acid responsive behaviour of bulky phosphonium-based ILs is elucidated using a mixed experimental and computational approach.

Hydrogen bond basicity of ionic liquids and molar entropy of hydration of salts as major descriptors in the formation of aqueous biphasic systems

Aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and conventional salts have been largely investigated and successfully used in separation processes, for which the determination of the corresponding ternary phase diagrams is a prerequisite. However, due the large number of ILs that can be prepared and their high structural versatility, it is impossible to experimentally cover and characterize all possible combinations of ILs and salts that may form ABS. The development of tools for the prediction and design of IL-based ABS is thus a crucial requirement. Based on a large compilation of experimental data, a correlation describing the formation of IL-based ABS is shown here, based on the hydrogen-bonding interaction energies of ILs (EHB) obtained by the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) and the molar entropy of hydration of the salt ions. The ability of the proposed model to predict the formation of novel IL-based ABS is further ascertained.

Mechanisms ruling the partition of solutes in ionic-liquid-based aqueous biphasic systems - the multiple effects of ionic liquids

In the past decade, the remarkable potential of ionic-liquid-based aqueous biphasic systems (IL-based ABSs) to extract and purify a large range of valued-added biocompounds has been demonstrated. However, the translation of lab-scale experiments to an industrial scale has been precluded by a poor understanding of the molecular-level mechanisms ruling the separation or partition of target compounds between the coexisting phases. To overcome this limitation, we carried out a systematic evaluation of specific interactions, induced by ILs and several salts used as phase-forming components, and their impact on the partition of several solutes in IL-based ABSs. To this end, the physicochemical characterization of ABSs composed of imidazolium-based ILs, three salts (Na2SO4, K2CO3 and K3C6H5O7) and water was performed. The ability of the coexisting phases to participate in different solute-solvent interactions (where "solvent" corresponds to each ABS phase) was estimated based on the Gibbs free energy of transfer of a methylene group between the phases in equilibrium, ΔG(CH2), and on the Kamlet-Taft parameters - dipolarity/polarizability (π*), hydrogen-bonding donor acidity (α) and hydrogen-bonding acceptor basicity (β) - of the coexisting phases. Relationships between the partition coefficients, the phase properties expressed as Kamlet-Taft parameters and COSMO-RS descriptors were established, highlighting the ability of ILs to establish specific interactions with given solutes. The assembled results clearly support the idea that the partition of solutes in IL-based ABSs is due to multiple effects resulting from both global solute-solvent and specific solute-IL interactions. Solute-IL specific interactions are often dominant in IL-based ABSs, explaining the higher partition coefficients, extraction efficiencies and selectivities observed with these systems when compared to more traditional ones majorly composed of polymers.

An integrated process for enzymatic catalysis allowing product recovery and enzyme reuse by applying thermoreversible aqueous biphasic systems

Thermoreversible aqueous biphasic systems (ABS) composed of ammonium-based zwitterions (ZIs) and polymers are here disclosed to act as integrated bioreaction-separation processes. The biocatalytic reaction involving laccase occurs in homogeneous media, after which small changes in temperature induce the formation of two phases and the complete separation of the enzyme from the products in a single-step. These systems also allow the recover and reuse of the enzyme, along with the ZI-rich phase, contributing towards the development of sustainable biocatalytic processes.

Alternative probe for the determination of the hydrogen-bond acidity of ionic liquids and their aqueous solutions

Although highly relevant to a priori select adequate solvents for a given application, the determination of the hydrogen-bond acidity or proton donor ability of aqueous solutions of ionic liquids is a difficult task due to the poor solubility of the commonly used probes in aqueous media. In this work, we demonstrate the applicability of the pyridine-N-oxide probe to determine the hydrogen-bond acidity of both neat ionic liquids and their aqueous solutions, based on ¹³C NMR chemical shifts, and the suitability of these values to appraise the ability of ionic liquids to form aqueous two-phase systems.

Mechanism of ionic-liquid-based acidic aqueous biphasic system formation

This work represents a major contribution to the understanding of ionic liquid-based acidic aqueous biphasic system formation and application.

Understanding the fundamentals of acid-induced ionic liquid-based aqueous biphasic system

This work describes the fundamentals of acid-induced ionic liquid-based ABS system and focuses on understanding the properties of such distinctive system.

A Triple Salting-Out Effect is Required for the Formation of Ionic-Liquid-Based Aqueous Multiphase Systems

Novel aqueous multiphase systems (MuPSs) formed by quaternary mixtures composed of cholinium-based ionic liquids (ILs), polymers, inorganic salts, and water are reported herein. The influence of several ILs, polymers, and salts was studied, demonstrating that a triple salting-out is a required phenomenon to prepare MuPSs. The respective phase diagrams and "tie-surfaces" were determined, followed by the evaluation of the effect of temperature. Finally, the remarkable ability of IL-based MuPSs to selectively separate mixtures of textile dyes is shown.

Designing the thermal behaviour of aqueous biphasic systems composed of ammonium-based zwitterions

The ability of water-soluble ammonium-based zwitterions (ZIs) to form aqueous biphasic systems (ABS) in presence of salts aqueous solutions is here disclosed for the first time. These systems are thermoreversible at temperatures close to room temperature and further allow the design of their thermal behavior, from an upper critical solution temperature (UCST) to a lower critical solution temperature (LCST), by increasing the ZIs alkyl chains length. The investigated thermoreversible ABS are more versatile than typical liquid-liquid systems, and can be applied in a wide range of temperatures and compositions envisaging a target separation process.

Simultaneous extraction and concentration of water pollution tracers using ionic-liquid-based systems

Human activities are responsible for the release of innumerous substances into the aquatic environment. Some of these substances can be used as pollution tracers to identify contamination sources and to prioritize monitoring and remediation actions. Thus, their identification and quantification are of high priority. However, due to their presence in complex matrices and at significantly low concentrations, a pre-treatment/concentration step is always required. As an alternative to the currently used pre-treatment methods, mainly based on solid-phase extractions, aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and K₃C₆H₅O₇ are here proposed for the simultaneous extraction and concentration of mixtures of two important pollution tracers, caffeine (CAF) and carbamazepine (CBZ). An initial screening of the IL chemical structure was carried out, with extraction efficiencies of both tracers to the IL-rich phase ranging between 95 and 100%, obtained in a single-step. These systems were then optimized in order to simultaneously concentrate CAF and CBZ from water samples followed by HPLC-UV analysis, for which no interferences of the ABS phase-forming components and other interferents present in a wastewater effluent sample have been found. Based on the saturation solubility data of both pollution tracers in the IL-rich phase, the maximum estimated concentration factors of CAF and CBZ are 28595- and 8259-fold. IL-based ABS can be thus envisioned as effective pre-treatment techniques of environmentally-related aqueous samples for a more accurate monitoring of mixtures of pollution tracers.

Ionic liquids in chromatographic and electrophoretic techniques: toward additional improvements in the separation of natural compounds

Due to their unique properties, in recent years, ionic liquids (ILs) have been largely investigated in the field of analytical chemistry. Particularly during the last sixteen years, they have been successfully applied in the chromatographic and electrophoretic analysis of value-added compounds extracted from biomass. Considering the growing interest in the use of ILs in this field, this critical review provides a comprehensive overview on the improvements achieved using ILs as constituents of mobile or stationary phases in analytical techniques, namely in capillary electrophoresis and its different modes, in high performance liquid chromatography, and in gas chromatography, for the separation and analysis of natural compounds. The impact of the IL chemical structure and the influence of secondary parameters, such as the IL concentration, temperature, pH, voltage and analysis time (when applied), are also critically addressed regarding the achieved separation improvements. Major conclusions on the role of ILs in the separation mechanisms and the performance of these techniques in terms of efficiency, resolution and selectivity are provided. Based on a critical analysis of all published results, some target-oriented ILs are suggested. Finally, current drawbacks and future challenges in the field are highlighted. In particular, the design and use of more benign and effective ILs as well as the development of integrated (and thus more sustainable) extraction-separation processes using IL aqueous solutions are suggested within a green chemistry perspective.

Why are some cyano-based ionic liquids better glucose solvents than water?

Among different classes of ionic liquids (ILs), those with cyano-based anions have been of special interest due to their low viscosity and enhanced solvation ability for a large variety of compounds. Experimental results from this work reveal that the solubility of glucose in some of these ionic liquids may be higher than in water - a well-known solvent with enhanced capacity to dissolve mono- and disaccharides. This raises questions on the ability of cyano groups to establish strong hydrogen bonds with carbohydrates and on the optimal number of cyano groups at the IL anion that maximizes the solubility of glucose. In addition to experimental solubility data, these questions are addressed in this study using a combination of density functional theory (DFT) and molecular dynamics (MD) simulations. Through the calculation of the number of hydrogen bonds, coordination numbers, energies of interaction and radial and spatial distribution functions, it was possible to explain the experimental results and to show that the ability to favorably interact with glucose is driven by the polarity of each IL anion, with the optimal anion being dicyanamide.

Good's buffers as novel phase-forming components of ionic-liquid-based aqueous biphasic systems

Aiming at the development of self-buffering and benign extraction/separation processes, this work reports a novel class of aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and organic biological buffers (Good's buffers, GBs). A large array of ILs and GBs was investigated, revealing than only the more hydrophobic and fluorinated ILs are able to form ABS. For these systems, the phase diagrams, tie-lines, tie-line lengths, and critical points were determined at 25 °C. The ABS were then evaluated as alternative liquid-liquid extraction strategies for two amino acids (L-phenylalanine and L-tryptophan). The single-step extraction efficiencies for the GB-rich phase range between 22.4 and 100.0 % (complete extraction). Contrarily to the most conventional IL-salt ABS, in most of the systems investigated, the amino acids preferentially migrate for the most biocompatible and hydrophilic GB-rich phase. Remarkably, in two of the studied ABS, L-phenylalanine completely partitions to the GB-rich phase while L-tryptophan shows a preferential affinity for the opposite phase. These results show that the extraction efficiencies of similar amino acids can be tailored by the design of the chemical structures of the phase-forming components, creating thus new possibilities for the use of IL-based ABS in biotechnological separations.

Aqueous biphasic systems composed of ionic liquids and acetate-based salts: phase diagrams, densities and viscosities

Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have been largely investigated as promising extraction and purification routes. In this context, the determination of their phase diagrams and the physical properties of the coexisting phases are of high relevance when envisaging their large-scale applications. Low viscosities improve the mass transfer and reduce energy consumptions, while the knowledge on their densities is important for the equipment design. In this work, novel phase diagrams for aqueous solutions of imidazolium-based ILs combined with acetate-based salts, namely KCH₃CO₂ or NaCH₃CO₂, are reported and discussed. The ability of the acetate-based salts to induce the phase separation not only depends on the ions hydration energy, but also on the concentration of "free" ions in solution. The tie-lines, tie-line lengths and critical points are also addressed. Experimental measurements of density and viscosity of the coexisting phases, for the different systems and at several compositions and temperatures, are additionally presented. The Othmer-Tobias and Bancroft equations are also applied to ascertain on the tie-lines coherence. It is here shown that low-viscous IL-based ABS, with a high difference in the densities of the coexisting phases, can be formed with organic and biodegradable salts thus offering enhanced features over conventional polymer-based systems.

One-step extraction and concentration of estrogens for an adequate monitoring of wastewater using ionic-liquid-based aqueous biphasic systems

Ethinylestradiol (EE2) is a synthetic hormone that has been recognized as one of the most prominent endocrine disruptors found in the aqueous environment. Nevertheless, the low content of EE2 in wastewater makes its identification/quantification unfeasible - a major drawback for the evaluation of its persistence and environmental impact. In this context, a novel extraction/concentration method for EE2 from wastewater is proposed here based on aqueous biphasic systems composed of ionic liquids (ILs). Aqueous biphasic systems formed by several hydrophilic ILs and KNaC4H4O6 were initially screened and optimized, with extraction efficiencies of EE2 for the IL-rich phase ranging between 92 and 100%. Remarkable results were obtained with systems that allow the complete extraction of EE2 in a single-step, and without loss of EE2 or the saturation of the extractive phase. Further, the concentration factors of EE2 attainable with these systems were investigated by a suitable manipulation of the composition of the phase-forming components and the corresponding volumes of the coexisting phases. An outstanding concentration of EE2 up to 1000-fold (from ng L-1 to μg L-1) in a single extraction and concentration step was achieved for the first time with IL-based aqueous biphasic systems. These systems are straightforwardly envisaged for the monitoring of wastewater as one-step extraction and concentration routes for a wide array of endocrine disrupting chemicals while allowing an adequate evaluation of their environmental impact.

Ionic liquid solutions as extractive solvents for value-added compounds from biomass

In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid-liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass-solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed.