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Separations

Separations - formerly Chromatography - is an international, peer-reviewed, open access journal on separation and purification science and technology in all areas of chemical, biological, physical science, and separation performance, published monthly online by MDPI.
The Central European Group of Separation Sciences (CEGSS) is affiliated with Separations and its members receive discounts on the article processing charges.

All Articles (2,380)

With the rapid expansion of the global lithium battery industry, the demand for lithium as a critical raw material continues to grow. Lithium precipitation mother liquor still contains considerable concentrations of lithium ions (Li+), but they generally exhibit a high sodium-to-lithium ratio, which makes the separation of lithium from sodium particularly challenging. Solvent extraction is recognized as a viable approach for challenging Li+/Na+ separation due to its high selectivity, operational flexibility, and scalability. A comprehensive assessment and comparison of various extraction systems are therefore essential to facilitate the sustainable recovery of lithium from precipitation mother liquor. This review summarizes the commonly used extraction systems, including organophosphorus extractants, ketone-based extractants, macrocyclic compounds, ionic liquids, and deep eutectic solvents. A systematic analysis is provided regarding their extraction mechanisms, applicable conditions, and respective advantages and disadvantages. Finally, perspectives and suggestions are offered on future research directions and improvement strategies for different extraction systems, along with an outlook on the potential of combined enhancement technologies.

5 February 2026

Generation of lithium precipitation mother liquor.

Primula vulgaris Huds., one of the 33 Primula L. species native to Europe, occurs across diverse habitats, including the biodiversity hotspot of the Prespa Lake region (NW Greece). Building on previous phytochemical studies, the present work provides the first detailed characterization of flavonoids from the aerial parts of the species growing wild in the area. Using classical chromatographic separation methods combined with spectrometric techniques, seven metabolites were isolated and structurally elucidated from the dichloromethane and methanol extracts. These included flavone (1), 2′-methoxyflavone (2), 3′-methoxyflavone (3), 3′-hydroxy-4′,5′-dimethoxyflavone (4), kaempferol-3-O-β-glucopyranosyl-(1→2)-β-glucopyranosyl-(1→6)-β-glucopyranoside (6), 3′-hydroxyflavone-4′-O-β-glucopyranoside (7) and 5,6,2′,3′,6′-pentamethoxyflavone (5), which was reported for the first time in this species. Additionally, the total phenolic content (TPC) of the methanol extract was determined using the Folin–Ciocalteu method, demonstrating 46.46 ± 2.48 mg GAE/g extract, while through the DPPH radical scavenging assay, it expressed moderate activity. Overall, these results provide novel insights into the flavonoid composition of Greek P. vulgaris and support its potential for further pharmacological investigations and herbal applications.

2 February 2026

Chemical structures of the isolated flavonoids. Flavone aglycones from dichloromethane extract (PvulP-DCM): flavone (1), 2′-methoxyflavone (2), 3′-methoxyflavone (3), 3′-hydroxy-4′,5′-dimethoxyflavone (4), 5,6,2′,3′,6′-pentamethoxyflavone (5). Flavonoid glycosides from methanol extract (PvulP-MeOH): kaempferol 3-O-β-glucopyranosyl-(1-2)-β-glucopyranosyl-(1-6)-β-glucopyranoside (6), 3′-hydroxyflavone- 4′-O-β-glucopyranoside (7).

Adsorption of Nystatin from Aqueous Solutions Using Nanoclay: Performance, Mechanisms, and Sustainability Aspects

  • Anna Karoline Freires de Sousa,
  • Anna Katharina Medeiros de Brito and
  • Meiry Gláucia Freire Rodrigues
  • + 6 authors

The continuous release of pharmaceutical compounds into aquatic environments poses significant challenges to environmental sustainability, as conventional wastewater treatment plants are often ineffective in removing recalcitrant and bioactive molecules. In this study, the adsorption performance of nanoclay was systematically evaluated for the removal of nystatin, a polyene antifungal of emerging environmental concern, from aqueous solutions. The effects of solution pH, adsorption kinetics, equilibrium isotherms, and adsorption mechanisms were investigated under environmentally relevant conditions. Nanoclay exhibited outstanding removal efficiency, exceeding 98% across a wide pH range (3–11), thereby demonstrating strong operational robustness and minimal sensitivity to pH variations. Structural and spectroscopic analyses (XRD and FTIR) confirmed that adsorption occurred predominantly on the external surface of the nanoclay, without significant disruption of its lamellar structure, and was governed mainly by hydrophobic interactions and hydrogen bonding. Kinetic data were best described by the pseudo-second-order model, with rapid equilibrium achieved within approximately 20 min, indicating high affinity between nystatin and the adsorbent surface. Equilibrium data were best fitted by the Sips isotherm model, reflecting surface heterogeneity and a favorable adsorption process, with a high maximum adsorption capacity of approximately 911 mg/g. A preliminary cost analysis revealed low raw material costs, while energy consumption, particularly during drying, was identified as the main economic limitation. Overall, the results highlight Nanoclay as an efficient, robust, and promising adsorbent for the sustainable removal of hydrophobic pharmaceutical contaminants from water and wastewater.

2 February 2026

XRD pattern of nanoclay before (a) and after Nystatin adsorption (b).

The genus Isaria is a group of abundant and widely distributed entomopathogenic fungi that plays an important role in the history of traditional Chinese medicine. Entomopathogenic fungi with medicinal value were collected from the field, and optimal temperature and growth media compositions were investigated to establish a theoretical foundation for the future development of these strains. A strain of Isaria cateniobliqua, designated ICF, was isolated from soil in the Hualongshan National Nature Reserve in southern Shaanxi. The optimal cultivation temperature and nutrient solution were screened, and the effects of subcultivation on mycelium production, metabolite production, and hydroxyl radical scavenging activity of strain ICF were investigated. The optimal growth temperature for strain ICF was determined to be 21 °C, with the ideal culture medium consisting of glucose and tussah silkworm pupa powder supplemented with KH2PO4 and MgSO4. Mycelium production and cordycepin content peaked in the fourth generation (G4), whereas peak metabolite production and cordycepic acid production occurred in the fifth generation (G5). Polysaccharide content was highest in the first generation (G1), and hydroxyl radical scavenging activity was optimal in G4. Exploring the optimal culture conditions of the strain provides a theoretical basis for its development, utilization, and industrial production for medicinal applications.

2 February 2026

Morphological characteristics of strain ICF. (a,b): The obverse and reverse of the strain ICF cultured for 30 d; (c–h): The microscopic features of the strain ICF. Bar = 10 μm.

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Separations - ISSN 2297-8739