On the use of ionic liquids as adjuvants in PEG-(NH4)2SO4 aqueous biphasic systems: Phase diagrams behavior and the effect of IL concentration on myoglobin partition

Recycling of metals from LiFePO4 battery cathode material by using ionic liquid based-aqueous biphasic systems

Lithium-ion batteries are essential for electric vehicles and energy storage devices. With the increasing demand for their production and the concomitant surge in waste generation, the need for an efficient and environmentally friendly recycling process has become imperative. This work presents a new approach for recycling of metals from the LiFePO4 (LFP) cathode material. The cathode material was first leached by a HCl solution without an oxidizing agent. Subsequently, an ionic-liquid-based aqueous biphasic system (IL-based ABS) was used for the separation of lithium and iron from leachate solutions, followed by a precipitation process. The influence of the acid concentration, solid-to-liquid ratio and leaching time on the leaching yield was investigated. UV-vis absorption spectra revealed the presence of mixed-valent iron in the leachate, with 83 ± 1% Fe(ii) and 17 ± 1% Fe(iii). The ABS systems comprised tributyltetradecylphosphonium chloride [P44414]Cl and a salting-out agent (HCl or NaCl). The extraction percentage of iron reached 90% and less than 1% of lithium was extracted under the studied optimal conditions. Further enhancement of iron extraction, reaching 98%, was achieved via a two-stage cross-current extraction process. Iron was precipitated from the loaded IL phase with an efficiency of 97% as Fe(OH)2 and Fe(OH)3, using an aqueous ammonia solution. Lithium was precipitated as Li3PO4 with a lithium purity of 99.5% by adding K3PO4 solution. The ionic liquid used in the process was efficiently regenerated and used in four extraction cycles with no activity decline, with an extraction percentage of 90% of iron in each cycle.

Aqueous Two-Phase Systems Based on Ionic Liquids and Deep Eutectic Solvents as a Tool for the Recovery of Non-Protein Bioactive Compounds—A Review

Aqueous two-phase systems (ATPS) based on ionic liquids (IL) and deep eutectic solvents (DES) are ecofriendly choices and can be used to selectively separate compounds of interest, such as bioactive compounds. Bioactive compounds are nutrients and nonnutrients of animal, plant, and microbial origin that benefit the human body in addition to their classic nutritional properties. They can also be used for technical purposes in food and as active components in the chemical and pharmaceutical industries. Because they are usually present in complex matrices and low concentrations, it is necessary to separate them in order to increase their availability and stability, and ATPS is a highlighted technique for this purpose. This review demonstrates the application of ATPS based on IL and DES as a tool for recovering nonprotein bioactive compounds, considering critical factors, results and the most recent advances in this field. In addition, the review emphasizes the perspectives for expanding the use of nonconventional ATPS in purification systems, which consider the use of molecular modelling to predict experimental conditions, the investigation of diverse compounds in phase-forming systems, the establishment of optimal operational parameters, and the verification of bioactivities after the purification process.

Extraction and Purification of Capsaicin from Capsicum Oleoresin Using a Combination of Tunable Aqueous Polymer-Phase Impregnated Resin (TAPPIR) Extraction and Chromatography Technology

Capsaicin, which mainly comes from pepper, exhibits anticancer, antioxidant, and anti-obesity properties. This work aims to construct a comprehensive technology for the extraction and purification of capsaicin from capsicum oleoresin. The tunable aqueous polymer phase impregnated HZ816 resins were selected in extraction step. In the extraction process, 3 g of impregnated HZ816 macroporous resin was employed per system. The results showed that a higher molecular weight of Polyethylene glycol (PEG) and 1-ethyl-3-methyl imidazolium acetate ([Emim] [OAc]) are more beneficial to the improvement of the yield of capsaicin. Screening experiment using fractional factorial designs indicated that the amount of sample loading, pH, and concentration of [Emim] [OAc] and PEG 6000 significantly affect the yield of capsaicin. Mathematical models of capsaicin yield in tunable aqueous polymer-phase impregnated resins were established and optimum condition was obtained using response surface methodology. The optimum impregnated phase was the polymer phase of an aqueous two-phase system which contained 18.5% (w/w) PEG6000, 15% (w/w) sodium citrate, and 10% (w/w) [Emim] [OAc] at pH 6.5. Under the optimal conditions, the yield of capsaicin reached 95.82% when the extraction system contains 0.25 g capsicum oleoresin. Ultimately, capsaicinoids extract was purified by reverse-phase resin (SKP-10-4300) chromatographic column. The capsaicin recovery and purity achieved 85% and 92%, respectively.