Aleksandra Dimitrijević

Food colorants play an important role in the food industry; however, their accurate determination, separation, and control are essential to ensure food quality and safety. Brilliant Blue FCF (E133) is a synthetic dye widely used in food products due to itsintense color and high stability. In this study, ionic liquid-based aqueous biphasic systems (ABSs) composed of salicylate-based ionic liquids (ILs) and potassium carbonate (K2CO3) were investigated as alternative extraction platforms for the separation of E133. Initially, phase diagrams were constructed to evaluate the biphasic behavior of the investigated systems and to assess the influence of IL cation structure on phase formation. Subsequently, the extraction performance of selected IL-ABSs toward E133 was evaluated. The tested systems demonstrated excellent extraction efficiency, reaching 99.48% and 99.55%. These findings highlight the potential of salicylate-based IL-ABSs as efficient, tunable, and sustainable platforms for the extraction and separation of food-related compounds.

Resveratrol (RSV) is a naturally occurring polyphenolic compound that has attracted considerable attention in recent decades due to its pronounced antioxidant activity and therapeutic potential, including anti-inflammatory, cardioprotective, and anticancer effects. However, its broader application is significantly limited by poor aqueous solubility. In this study, aqueous solutions of cholinium salicylate ([Ch][Sal]) were investigated as a potential medium for improving RSV solubilization. The influence of ionic liquid concentration on RSV solubility was evaluated to gain insight into the interactions governing the dissolution process. Additionally, the antioxidant activity of RSV in [Ch][Sal] aqueous media was assessed to determine whether the ionic liquid environment affects its functional properties.

This work used activated carbon material obtained by chemical activation of abundantly available agricultural sunflower waste residues to remove metol (4-(methylamino) phenol sulfate, MTL) from aqueous solutions. The adsorbent structure was characterized using SEM-EDS and FT-IR spectroscopy. A modified screen-printed carbon electrode (SPCE) with gold nanoparticles synthesized using the Laser Ablation Synthesis in Solution (LASIS) method was used to detect MTL. The successful LASIS formation of gold nanoparticles was confirmed by the specific dark burgundy–red color. TEM measurements showed uniform pseudo-spherical particles with an average diameter of 7.9 ± 0.2 nm. The modified electrode showed improved electrochemical activity, which was confirmed by comparing it with an unmodified electrode using cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode was subsequently used to optimize the MTL detection conditions. UV–Vis spectroscopy was used to optimize the adsorption conditions, with the optimal values for pH and contact time found to be 8 and 120 min, respectively. The electrochemical detection of MTL was performed using differential pulse voltammetry, and the linear calibration range was established for concentrations ranging from 0.73–49.35 µM. The obtained limits of detection (LOD) and quantification (LOQ) were 0.06 µM and 0.2 µM, respectively. The efficiency of MTL removal was 100% after a contact time of 1 min and remained at 100% after 120 min.

The escalating production and use of lithium-ion batteries (LIBs) have led to a pressing need for efficient and sustainable methods for recycling valuable metals such as cobalt, nickel, manganese, and lithium from spent cathode materials. Traditional hydrometallurgical leaching approaches, based on mineral acids, face significant limitations, including high reagent consumption, secondary pollution, and poor selectivity. In recent years, deep eutectic solvents (DESs) and ionic liquids (ILs) have emerged as innovative, environmentally benign alternatives, offering tunable physicochemical properties, enhanced metal selectivity, and potential for reagent recycling. This review provides a comprehensive analysis of the current state and prospects of leaching LIB cathode materials using DES and ILs. We summarize the structural diversity and composition of common LIB cathodes, highlighting their implications for leaching strategies. The mechanisms, efficiency, and selectivity of metal dissolution in various DES- and IL-based systems are critically discussed, drawing on recent advances in both laboratory and real-sample studies. Special attention is given to the unique extraction mechanisms facilitated by complexation, acid–base, and redox interactions in DES and ILs, as well as to the effects of key operational parameters. A comparative analysis of DES- and IL-based leaching is presented, with discussion of their advantages, challenges, and industrial potential. While DES offers low toxicity, biodegradability, and cost-effectiveness, it may suffer from limited solubility or viscosity issues. Conversely, ILs provide remarkable tunability and metal selectivity but are often hampered by higher costs, viscosity, and environmental concerns. Finally, the review identifies critical bottlenecks in upscaling DES and IL leaching technologies, including long-term solvent stability, metal recovery purity, and economic viability. We also highlight research priorities that emphasize applying circular hydrometallurgy and life-cycle assessment to improve the sustainability of battery recycling.

The widespread use of activated carbon (AC) as an adsorbent in diverse applications generates substantial amounts of AC waste, posing environmental and disposal challenges. Therefore, effective AC regeneration is essential to enhance the sustainability of adsorption-based technologies. However, conventional regeneration methods often involve harsh chemicals or energy-intensive processes, limiting environmental and economic feasibility. In this study, the regeneration of commercial AC saturated with synthetic dyes Acid Blue 9 (AB9) and Acid Yellow 23 (AY23) is investigated using aqueous solutions of ionic liquids (ILs) as a green alternative. A set of ILs with varying cation–anion structures was synthesized and screened for regeneration performance, where [TBP][Sal] was identified as the most effective. Process parameters such as IL concentration, temperature, time, and solid-to-liquid ratio were optimized using response surface methodology, achieving regeneration efficiencies of up to 99% for AB9-AC and 80% for AY23. These efficiencies persisted over three cycles, while adsorption capacity remained unchanged for AY23 and decreased by ~40% for AB9. To improve sustainability, a preliminary study was conducted by implementing an aqueous biphasic system for IL and dye concentration from the post-regeneration solution. This integrated strategy presents a promising step toward the development of near-zero waste adsorption–regeneration cycles for AC adsorption applications.

The increasing demand for lithium-ion batteries (LIBs) and their limited lifespan emphasize the urgent need for sustainable recycling strategies. This study investigates the application of tetrabutylphosphonium-based ionic liquids (ILs) as alternative leaching agents for recovering critical metals, Li(I), Co(II), Ni(II), and Mn(II), from spent NMC cathode materials. Initial screening experiments evaluated the leaching efficiencies of nine tetrabutylphosphonium-based ILs for Co(II), Ni(II), Mn(II), and Li(I), revealing distinct metal dissolution behaviors. Three ILs containing HSO₄⁻, EDTA²⁻, and DTPA³⁻ anions exhibited the highest leaching performance and were selected for further optimization. Key leaching parameters, including IL and acid concentrations, temperature, time, and solid-to-liquid ratio, were systematically adjusted, achieving leaching efficiencies exceeding 90%. Among the tested systems, [TBP][HSO₄] enabled near-complete metal dissolution (~100%) even at room temperature. Furthermore, an aqueous biphasic system (ABS) was investigated utilizing [TBP][HSO₄] in combination with ammonium sulfate, enabling the complete extraction of all metals into the salt-rich phase while leaving the IL phase metal-free and potentially suitable for reuse, indicating the feasibility of integrating leaching and extraction into a continuous, interconnected process. This approach represents a promising step forward in LIB recycling, highlighting the potential for sustainable and efficient integration of leaching and extraction within established hydrometallurgical frameworks.

Pesticides used in agriculture can contaminate foods like fruits and vegetables, posing health risks to consumers and highlighting the need for effective residue monitoring. This study explores aqueous two-phase systems (ATPSs) comprising phosphonium or ammonium ionic liquids (ILs) combined with ammonium sulfate as an alternative pre-treatment method for extracting and concentrating the pesticides clomazone, pyraclostrobin, and deltamethrin from strawberry samples. Liquid–liquid equilibrium measurements for each ATPS were conducted, followed by extraction experiments to determine the most efficient systems for pesticide extraction. Results showed that all three pesticides migrated effectively to the IL-rich phase across the tested ATPSs. For the most promising system, tetrabutylphosphonium salicylate ([TBP][Sal]) with ammonium sulfate, extraction efficiencies for each pesticide exceeded 98% under optimized conditions for parameters such as pH, temperature, and ATPS composition. Application of this ATPS to strawberries resulted in significant pesticide preconcentration, reaching mg/L levels suitable for detection by liquid chromatography. The method’s sustainability was supported by green chemistry metrics, with AGREEprep and AGREE scores of 0.68 and 0.55, respectively, underscoring its alignment with eco-friendly practices.

This study investigates the impact of changing parameters on the photocatalytic degradation of carbofuran (CBF) using laser-treated TiO₂ nanotube arrays on a Ti mesh under simulated sunlight irradiation and assessing toxicity during photocatalytic degradation. Various parameters, including the stirring effect, light intensity, initial CBF concentration, and variation in the active surface area of laser-treated TiO₂ photocatalysts, were examined to determine their impact on degradation efficiency. The photodegradation kinetics were monitored using ultra-performance liquid chromatography with a PDA detector (UPLC-PDA) and UV-Vis spectrophotometry, while mineralization was assessed by a total organic carbon (TOC) analyzer. The photocatalytic degradation of CBF is enhanced by an increase in the active surface area of the TiO₂ photocatalyst, light intensity, and the introduction of stirring, but it decreases with an increase in the initial concentration of CBF. The toxicity assessments revealed that the cytotoxicity of CBF initially increased during the degradation process but decreased after further treatment, indicating the formation and subsequent breakdown of toxic intermediates. The phytotoxicity test showed that longer degradation times resulted in higher toxicity to plant growth. This study provides new insights into the photocatalytic degradation of CBF with TiO₂, the importance of parameter optimization for more efficient treatment, and the use of toxicity tests to confirm the success of the photocatalytic process.

Polyphenols are natural compounds with enhanced antioxidant properties. They are present in relatively high concentrations in fruit/vegetable by-products. Therefore, there is a need for the development of efficient and cost-effective methods for the separation and purification of these valuable compounds. Traditional extraction with organic solvents needs to be switched to novel methods that are more efficient, with reduced extraction times and low consumption of organic solvents. Aiming at developing sustainable processes for the separation and purification of phenolic compounds, we used three model compounds, namely resveratrol, quercetin, and gallic acid, to investigate ionic liquid-based aqueous biphasic systems (IL-ABSs) formed by cholinium-based IL in combination with polypropylene glycol with a molecular mass of 400 g/mol (PPG400). The ABS composition in the two-phase region was selected according to a previously determined phase diagram. Extraction studies indicated the preferential partition of resveratrol and quercetin toward the hydrophobic PPG-rich phase that is mainly dominated by its hydrophobic nature and the strong salting-out effect of ILs. On the other hand, due to its considerably hydrophilic nature, gallic acid preferentially migrates toward the IL phase. The achieved results from grape stem extract demonstrated high extraction efficiencies of cholinium dihydrogen phosphate (~99% for resveratrol for the PPG phase and 78% for gallic acid for the IL phase), with considerable selectivity, demonstrating promising outcomes for potential applications.