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Volume 13
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Separations, Volume 13, Issue 4 (April 2026) – 26 articles

Cover Story (view full-size image): Spent coffee grounds are more than a residue: they are a rich matrix of phenolic compounds and proteins with strong potential for biorefinery applications. This study explores hydrophilic and hydrophobic eutectic solvents, alone or combined with enzyme-assisted extraction, as alternative media for recovering these value-added fractions. Among 31 hydrophobic eutectic solvents and nine hydrophilic deep eutectic solvents, extraction performance was highly dependent on solvent composition. Camphor:oleic acid showed the highest phenolic recovery, while its combination with Cellic® CTec2 markedly enhanced protein extraction. The results highlight eutectic solvents as tunable platforms for converting coffee waste into functional ingredients through more sustainable extraction strategies. View this paper
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25 pages, 9970 KB  
Article
A Novel Fixed-Bed Process Integrated with Additional Disproportionation Reactors for Silane Production
by Qiang Geng, Tianshi Lan and Guoqiang Huang
Separations 2026, 13(4), 127; https://doi.org/10.3390/separations13040127 - 21 Apr 2026
Viewed by 739
Abstract
With the increase in the demand for electronic-grade high-purity silane in the semiconductor chip industry, it is of great significance to develop a green and economical method for silane production. Therefore, a novel energy-saving fixed-bed process was proposed innovatively. In this paper, the [...] Read more.
With the increase in the demand for electronic-grade high-purity silane in the semiconductor chip industry, it is of great significance to develop a green and economical method for silane production. Therefore, a novel energy-saving fixed-bed process was proposed innovatively. In this paper, the thermodynamics and kinetics of the trichlorosilane disproportionation system were studied, and the optimal reaction conditions for the resin catalyst were determined, which were used for the subsequent simulation. Based on the conventional DR1 + DR2 process (which includes one trichlorosilane disproportionation reactor (DR1) and one dichlorosilane disproportionation reactor (DR2)), by adding an additional disproportionation reactor to the TCS recycle loop and/or DCS recycle loop, three improved process configurations were designed, including 2DR1 + DR2, DR1 + 2DR2, and 2DR1 + 2DR2 processes. Then, combined with four-column heat integration, the HI + 2DR1 + 2DR2 process was proposed to solve the bottleneck problems of high energy consumption and large circulation flow rate. The results show that the HI + 2DR1 + 2DR2 process achieved the best energy-saving effect. The TCS recycle loop flow rate reduced by 36.87%, the DCS recycle loop flow rate reduced by 12.41%, total energy consumption decreased by 62.8%, and CO2 emissions decreased by 56.72%. The unit energy consumption is 13.8 kg steam/kg SiH4, and the silane purity is greater than 99.9999%. This design can be easily applied to the existing production process of the silane plant, achieving energy-saving and low-cost production of silane. Full article
(This article belongs to the Section Separation Engineering)
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16 pages, 6627 KB  
Article
Optimization of Process Conditions for the Separation and Purification of Erythromycin Thiocyanate Using Response Surface Methodology
by Yining Wang, Yinghua Sun, Wuying Li and Shuqian Xia
Separations 2026, 13(4), 126; https://doi.org/10.3390/separations13040126 - 21 Apr 2026
Viewed by 815
Abstract
A water acetone biphasic extraction system was developed for the separation and purification of erythromycin thiocyanate. Response surface methodology based on a Box-Behnken design was used to evaluate the effects of pH, liquid-to-solid ratio, extraction temperature, and acetone-to-water volume ratio on mass yield. [...] Read more.
A water acetone biphasic extraction system was developed for the separation and purification of erythromycin thiocyanate. Response surface methodology based on a Box-Behnken design was used to evaluate the effects of pH, liquid-to-solid ratio, extraction temperature, and acetone-to-water volume ratio on mass yield. All four variables influenced the extraction performance, and acetone-to-water volume ratio and liquid-to-solid ratio were the most significant factors. Under the optimized conditions of 50.5 °C, pH 9.2, a liquid-to-solid ratio of 3.0 mL/g, and an acetone-to-water volume ratio of 2.5 mL/mL, the mass yield reached 81.58 percent. The predicted and experimental values were in good agreement, confirming the adequacy of the model. The product obtained under the optimized conditions met the relevant requirements of the Chinese Pharmacopoeia. The proposed process is simple and effective, and provides a basis for the purification and scale up of erythromycin thiocyanate and related derivatives. Full article
(This article belongs to the Special Issue Design and Optimization of Extraction/Separation Processes for Natural Products)
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14 pages, 3637 KB  
Article
Effect of Sintering Temperature on Phase Evolution and Oil-Repellent Performance of TiO2–Carbon-Coated Stainless-Steel Mesh
by Kayla Laguana, Sonia Egenberger, Jack Tobin, Claudia Wong, Logan Lu, Jack G. Webster and Mingheng Li
Separations 2026, 13(4), 125; https://doi.org/10.3390/separations13040125 - 20 Apr 2026
Viewed by 1174
Abstract
This study investigates how sintering temperature affects phase evolution, titanium carbide (TiC) formation, and oil-repellent performance in TiO2–carbon-coated 304 stainless-steel mesh for oil–water separation applications. Coated meshes sintered at 400, 500, 600, 700, and 800 °C were evaluated using gravity-driven oil [...] Read more.
This study investigates how sintering temperature affects phase evolution, titanium carbide (TiC) formation, and oil-repellent performance in TiO2–carbon-coated 304 stainless-steel mesh for oil–water separation applications. Coated meshes sintered at 400, 500, 600, 700, and 800 °C were evaluated using gravity-driven oil permeation tests with 5W-20 motor oil and oil contact-angle measurements, while coating morphology, composition, and phase evolution were characterized by SEM, EDS, and XRD. Sintering temperature strongly influenced coating structure and wettability. Among the tested conditions, the mesh sintered at 600 °C showed the highest oil contact angle (105°) and the highest initial oil retention efficiency (80%), indicating the most favorable balance between oleophobicity and coating stability within the tested range. XRD analysis showed that 600 °C corresponded to the onset of the anatase-to-rutile transition and the initial formation of TiC. These results suggest that intermediate sintering temperatures can provide a favorable balance between retention of beneficial anatase content and enhanced interfacial interaction within the TiO2–carbon coating. Within the tested conditions, 600 °C was the best-performing sintering condition among the temperatures examined for this coating system. Full article
(This article belongs to the Section Separation Science in Energies)
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20 pages, 1205 KB  
Article
Moisture Reduction and Particle Charging Promotion for Enhanced Electrostatic Separation of Coal Gasification Fine Slag by Molecular Sieve
by Chaoyong Li, Hui Zhou, Haisheng Li, Yinghua Chen, Ziyin Xu, Jie Li, Qiqiang Gao and Qiang Zhao
Separations 2026, 13(4), 124; https://doi.org/10.3390/separations13040124 - 20 Apr 2026
Cited by 1 | Viewed by 708
Abstract
As an efficient dry separation technology, electrostatic separation exhibits significant potential for application in the sorting and recovery of carbon-rich resources from coal gasification fine slag (CGFS). The small particle size and high moisture content of CGFS particles are the main factors affecting [...] Read more.
As an efficient dry separation technology, electrostatic separation exhibits significant potential for application in the sorting and recovery of carbon-rich resources from coal gasification fine slag (CGFS). The small particle size and high moisture content of CGFS particles are the main factors affecting the efficiency of separation. This study proposes a method integrating particle moisture reduction and charging promotion based on molecular sieves, with the aim of investigating its feasibility in improving the electrostatic separation efficiency of CGFS particles. The results indicate that molecular sieves can effectively adsorb moisture from the ambient humid air and the surface of particles, allowing for rapid drying of wet particles. The reduction in moisture content on the particle surfaces significantly promotes their charging capability, creating favorable conditions for electrostatic separation. After molecular-sieve-assisted charging enhancement, the carbon content in the ash-enriched positive plate product decreased by 4.96%, while the carbon content in the carbon-enriched negative plate product increased by 12.15%, indicating a significant improvement in carbon–ash separation efficiency. Correspondingly, the decarbonization efficiency of the positive plate and carbon recovery efficiency of the negative plate were increased by 21.30% and 52.17%, respectively. Furthermore, when the moisture content exceeds 10%, the phenomenon of inter-particle agglomeration can adversely affect the separation of carbon and ash particles. The most suitable operating conditions are a moisture content no higher than 10%, an electric field density of 30 kV/m, a filling molecular sieve of 400 g, and a gas velocity of 12 m/s (volumetric flow rate 84.78 m3/h). In practical industrial applications, it is advisable to consider pre-treating the particles for drying or employing secondary separation to enhance sorting accuracy. Full article
(This article belongs to the Special Issue The Latest Progress in the Coal-Based Solid Waste Particle Separation)
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17 pages, 2664 KB  
Article
Deep Purification of Manganese Sulfate Electrolyte by Sodium Dimethyldithiocarbamate Chelation Precipitation: Process and Selective Coordination Mechanism
by Tong Liu, Fei Zhu, Xijun Tian, Zhenping Cai, Kai Huang and Song Chen
Separations 2026, 13(4), 123; https://doi.org/10.3390/separations13040123 - 18 Apr 2026
Viewed by 711
Abstract
This study addresses the issue of insufficient product purity caused by the co-deposition of three major impurity ions—zinc, nickel, and lead—during the electrodeposition process of high-purity manganese. A targeted deep purification method for manganese sulfate electrolyte was developed using dithiocarbamate chelating agents (sodium [...] Read more.
This study addresses the issue of insufficient product purity caused by the co-deposition of three major impurity ions—zinc, nickel, and lead—during the electrodeposition process of high-purity manganese. A targeted deep purification method for manganese sulfate electrolyte was developed using dithiocarbamate chelating agents (sodium dimethyldithiocarbamate, SDD). By optimizing key process parameters such as precipitant concentration, reaction temperature, reaction time, and solution pH, combined with density functional theory (DFT) calculations, to elucidate the selective impurity removal mechanism at the molecular level, a novel process for the efficient synergistic removal of Zn2+, Ni2+, and Pb2+ was established. The results showed that under the conditions of precipitant concentration of 1 g/L, solution pH of 6.5, reaction temperature of 55 °C, and reaction time of 2 h, the residual concentrations of Zn, Ni, and Pb in the electrolyte were all below 0.2 mg/L. DFT calculations revealed that SDD coordinates with metal ions through four sulfur atoms, and the absolute values of binding energies follow the order Ni2+ > Pb2+ > Zn2+ > Mn2+, indicating thermodynamically preferential capture of impurity ions. After purification, the manganese metal obtained by electrodeposition from the manganese sulfate solution achieved a purity exceeding 99.999%, with Zn, Ni, and Pb contents of 0.11 mg/kg, 0.038 mg/kg, and 0.05 mg/kg, respectively, meeting the raw material requirements for semiconductor-grade copper–manganese alloy targets. Full article
(This article belongs to the Section Separation Engineering)
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13 pages, 1321 KB  
Article
Extractive Purification of Sulfur and Nitrogen Fuel Contaminants Using p-Toluenesulfonic Acid-Based Deep Eutectic Solvents
by Salim Mokraoui, Lahssen El Blidi, Irfan Wazeer, Attiyah A. Al-Zahrani and Mohamed K. Hadj-Kali
Separations 2026, 13(4), 122; https://doi.org/10.3390/separations13040122 - 18 Apr 2026
Viewed by 583
Abstract
This study demonstrates the high efficiency and selectivity of p-toluenesulfonic acid-based deep eutectic solvents (DESs) for simultaneous extractive denitrogenation (EDN) and desulfurization (EDS) of model fuel. Three DESs—TBPB:PTSA, TBAB:PTSA, and ChCl:PTSA (1:1 molar ratio)—were synthesized and evaluated for their effectiveness against representative heteroaromatic [...] Read more.
This study demonstrates the high efficiency and selectivity of p-toluenesulfonic acid-based deep eutectic solvents (DESs) for simultaneous extractive denitrogenation (EDN) and desulfurization (EDS) of model fuel. Three DESs—TBPB:PTSA, TBAB:PTSA, and ChCl:PTSA (1:1 molar ratio)—were synthesized and evaluated for their effectiveness against representative heteroaromatic pollutants: thiophene, dibenzothiophene, pyridine, and carbazole. The phosphonium-based TBPB:PTSA exhibited the highest extraction performance, achieving over 96% removal of nitrogen species and up to 85% removal of sulfur species at 40 °C. Increasing the temperature enhanced desulfurization by reducing viscosity, thereby improving mass transfer kinetics. Additionally, a 3:1 ratio of DES to fuel provided an optimal balance between solvent economy and operational efficiency. Denitrogenation was driven by strong acid–base protonation facilitated by PTSA, while desulfurization was governed by π–π and dispersion interactions, modulated by the hydrophobicity of the cations. The DES achieved nearly quantitative nitrogen removal and satisfactory sulfur extraction after three reuse cycles, while multistage operation enabled complete purification within four extraction steps. 1H NMR analysis confirmed that no DES components were found in the raffinate phase, verifying the immiscibility and stability of the solvent. These results indicate that TBPB:PTSA is a robust, regenerable, and environmentally benign solvent, effectively enabling simultaneous EDN–EDS of hydrocarbon fuels and positioning it as a promising green alternative to traditional hydrogen-based refining methods. Full article
(This article belongs to the Special Issue The Application of Ionic Liquids and Deep Eutectic Solvents in Separation and Extraction Processes)
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22 pages, 3745 KB  
Article
Molecularly Imprinted Polymer with Photocatalytic Activity for the Adsorption and Degradation of Naproxen and Its Application in Real Water Samples
by Diana Samantha Villarreal-Lucio, Karla Ximena Vargas-Berrones, Brenda V. Loera-García, Vanessa Sarahí Galván-Romero, Carolina López-Saldaña, Raúl Ocampo-Pérez, Héctor Hernández-Mendoza and Rogelio Flores-Ramírez
Separations 2026, 13(4), 121; https://doi.org/10.3390/separations13040121 - 17 Apr 2026
Viewed by 1146
Abstract
This research focused on the development and characterisation of molecularly imprinted polymers (MIPs) modified with titanium dioxide (TiO2) for the adsorption and photocatalytic degradation of sodium naproxen (NPX). Different percentages of TiO2 (5% and 25%) were tested and compared to [...] Read more.
This research focused on the development and characterisation of molecularly imprinted polymers (MIPs) modified with titanium dioxide (TiO2) for the adsorption and photocatalytic degradation of sodium naproxen (NPX). Different percentages of TiO2 (5% and 25%) were tested and compared to non-imprinted polymers (NIPs). FT-IR analysis confirmed the interaction between methacrylic acid and TiO2, promoting the formation of specific binding sites and presenting a good imprinting factor. The results showed that the MIP with 5% TiO2 had the highest adsorption and retention capacity, attributed to the imprinting effect and the reduced interference from TiO2. The surface of the MIPs is heterogeneous, as it was indicated by the Freundlich isotherm model. The KF for the MIP with 25% of TiO2 was higher than for the materials with 5%; values for the MIP/TiO2 5% and the NIP/TiO2 5% KF were 4.808 and 4.163 (mg/g)(L/mg)1/n respectively, while for the MIP/TiO2 25% was 6.542 (mg/g)(L/mg)1/n and for the NIP/TiO2 25% it was 2.736 (mg/g)(L/mg)1/n. Kinetic studies followed the pseudo-second-order model, suggesting more active binding sites in MIPs. Photocatalytic experiments achieved 60% degradation, demonstrating the degradation performance of MIPs; however, this behavior is restricted by the slow degradation of NPX. The materials were evaluated using a water sample (Querétaro River, México); the sample was preconcentrated and analyzed, detecting a concentration of 0.332 mg/L of NPX. This finding highlights the MIPs’ potential application in environmental monitoring and treatment; nevertheless, due to the recalcitrant nature of NPX, MIPs should be used along with other advanced treatment methods to achieve effective removal. Full article
(This article belongs to the Special Issue Molecularly Imprinting Polymers for Separation and Detection)
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17 pages, 3619 KB  
Article
Fabrication of Hollow Fiber Loose Nanofiltration Membrane via Metal-Organic Bonding and PA-PEI Dual Coating for Superior Dye/Salt Separation
by Mengmeng Jia, Mengchen Shi, Yi Wang and Xiaofeng Fang
Separations 2026, 13(4), 120; https://doi.org/10.3390/separations13040120 - 16 Apr 2026
Cited by 1 | Viewed by 903
Abstract
The efficient removal of dyes and separation from dissolved salts are crucial for the recovery of valuable resources from saline textile wastewater. In this study, hollow fiber membranes were fabricated using the non-solvent-induced phase separation (NIPS) method and then improved with a dual-coating [...] Read more.
The efficient removal of dyes and separation from dissolved salts are crucial for the recovery of valuable resources from saline textile wastewater. In this study, hollow fiber membranes were fabricated using the non-solvent-induced phase separation (NIPS) method and then improved with a dual-coating process to create effective nanofiltration (NF) membranes. First, hollow fiber substrates with Fe3+ were fabricated using NIPS. Subsequently, the inner surface of the membrane was coated with phytic acid (PA) and polyethyleneimine (PEI), which increased the thickness of the separation layer and reduced the size of the surface pores, thereby improving the separation efficiency. The loose NF membrane exhibited superior water permeance (pure water permeability of 280 L·m−2·h−1·bar−1) and, with dye rejection rates consistently exceeding 95%, also remarkable dye/salt selectivity (with separation factors of CR/NaCl: 64.08, CR/Na2SO4: 21.21, CBB/NaCl: 14.75, and CBB/Na2SO4: 10.74). The flux recovery of the membrane was over 80% for humic acid, and the membrane exhibited favorable stability under acidic and alkaline conditions, confirming its excellent antifouling and stability performance. In conclusion, this study presents a straightforward and effective approach for fabricating hollow fiber loose NF membranes, underscoring their potential for treating hypersaline wastewater and resource recovery. Full article
(This article belongs to the Special Issue Membrane Separation Process for Water Treatment)
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16 pages, 8369 KB  
Article
Separation and Extraction of Rhenium from Waste Acid via Selective Precipitation and Atmospheric Pressure Leaching
by Hancheng Mao, Shengdong Wang, Muyao Lu, Haibei Wang and Denggao Zhang
Separations 2026, 13(4), 119; https://doi.org/10.3390/separations13040119 - 15 Apr 2026
Viewed by 1051
Abstract
This study presents a combined process of sulfide precipitation followed by hydrogen peroxide leaching for rhenium recovery from copper smelting waste acid under ambient temperature and pressure. The process first removed copper through selective sulfide precipitation, then achieved co-precipitation of rhenium and arsenic [...] Read more.
This study presents a combined process of sulfide precipitation followed by hydrogen peroxide leaching for rhenium recovery from copper smelting waste acid under ambient temperature and pressure. The process first removed copper through selective sulfide precipitation, then achieved co-precipitation of rhenium and arsenic to obtain a rhenium-rich precipitate. Subsequently, exploration of rhenium-containing precipitate leaching using H2O2 solution was conducted under isothermal conditions at 20 °C. The effects of H2O2 concentration, liquid-to-solid ratio, acidity, and leaching time rhenium extraction efficiency were examined systematically. The optimal leaching conditions were determined as: H2O2 concentration of 150 g/L, liquid-to-solid ratio of 5:1 mL/g, stirring speed of 350 r/min, and leaching time of 30 min. Under these conditions, the leaching conversions of rhenium and arsenic reached 96.0% and 93.8%, respectively. Through characterization of precipitate and leaching residue using ICP, SEM-EDS, XRD, and XPS analyses, the process and related reactions were elucidated. Results demonstrated that low-valence rhenium oxides and sulfides serve as the main reactive species during H2O2 leaching, whereas organic sulfur, high-valence oxides, and copper sulfide remained stable and resistant to leaching. Selective precipitation of copper effectively eliminated insoluble metal sulfides from rhenium-containing precipitates, thereby enabling efficient separation of rhenium under mild conditions. Full article
(This article belongs to the Special Issue Research on Metal Resource Recycling and Efficient Extraction Technologies)
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22 pages, 14111 KB  
Article
Study on the Dewatering Mechanism of Fine Phosphate Tailings Slurrys Based on the Particle-Agent Interaction and Sedimentation Property
by Fang Li, Yuping Fan, Yuanpeng Fu, Xiaomin Ma, Xianshu Dong, Yangge Zhu, Wei Xiao and Wenjie Fang
Separations 2026, 13(4), 118; https://doi.org/10.3390/separations13040118 - 15 Apr 2026
Viewed by 1008
Abstract
Fluorapatite is a typical phosphate rock resource. Fluorapatite tends to generate fine mud agglomeration, which induces dehydration challenges owing to its inherently fine particle size and negative surface charge. In this paper, phosphate tailings slurries from a phosphate mine in Hubei Province, China, [...] Read more.
Fluorapatite is a typical phosphate rock resource. Fluorapatite tends to generate fine mud agglomeration, which induces dehydration challenges owing to its inherently fine particle size and negative surface charge. In this paper, phosphate tailings slurries from a phosphate mine in Hubei Province, China, were selected as the research object, and flocculation–dehydration experiments were conducted using anionic, cationic, and nonionic polyacrylamide (PAM) flocculants. The results show that the maximum settling velocity is 51 mm/s and the moisture content of filter cake is 41.54%, which were obtained when the unit consumption of cationic flocculant with molecular weight 12 million was 1000 g/t. The mechanism of sedimentation and dehydration was studied by infrared spectroscopy and a particle size analyzer. The results showed that polyacrylamide was effectively adsorbed on the mineral surface, and the size of flocs increased significantly. Finally, the mechanism of sedimentation and dehydration was proposed. It has important guiding significance for the efficient solid–liquid separation and water circulation of fluorapatite mineral processing wastewater. Full article
(This article belongs to the Special Issue Separation Technology in Mineral Processing)
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14 pages, 3118 KB  
Article
Dehydration Characteristics of Viscous Fine Coal in Compound Force-Field with Vibration and Airflow
by Jun Zhang, Ming Shao, Minghan Zhou, Lin Zhang, Yingguang Zuo, Lijun Wang and Yadong Zhang
Separations 2026, 13(4), 117; https://doi.org/10.3390/separations13040117 - 15 Apr 2026
Cited by 1 | Viewed by 1806
Abstract
The paper utilizes the synergy of vibration and hot air flow to form a composite force field, and low-quality fine coal with viscous moisture is subjected to ash removal. The vibration signals of the bed surface at different positions are collected online using [...] Read more.
The paper utilizes the synergy of vibration and hot air flow to form a composite force field, and low-quality fine coal with viscous moisture is subjected to ash removal. The vibration signals of the bed surface at different positions are collected online using an accelerometer, and the dominant force affecting the vibration behavior of the bed is analyzed using signal time-domain analysis. By examining the impact of the synergy between vibration and airflow on the ash removal effect of low-quality, viscous moisture coal, the response of the drying and sorting behavior of low-quality fine coal to this synergy is elucidated. Based on the study of the experimental results of dehydration and ash removal of −6 + 1 mm fine coal, under the synergy of temperature and load force field, when the air flow temperature is 90 °C, v = 0.65 m/s, and f = 20 Hz, the collision force range between particles is 120 nN–370 N, which is different from that between particles. The liquid bridge force is large, which can achieve the fracture of liquid bridges between particles and strengthen the loose fluidization of particles. In addition, based on the study of the vibration characteristics of the bed surface at different positions, the vibration along the y-axis direction plays a dominant role in the density segregation behavior of the bed particles. With the increase in gas velocity and vibration frequency, the ash content of the selected clean coal exhibits a trend of first decreasing and then increasing. At the same time, the ash segregation degree initially increases and then decreases. Moreover, under the conditions of v = 0.65 m/s and f = 20 Hz, the separation effect of fine coal is the best. The separation accuracy E values of 1–6 mm without fine particles are 0.06 g/cm3, and the ash content of the clean coal is 12.55%. Full article
(This article belongs to the Special Issue Research Progress of Gas–Solid Fluidized Dry Separation)
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16 pages, 2301 KB  
Article
Surface-Modified Waste Scallop Shell as a Flocculant and an Optical Method for Evaluating Flocculation Performance
by Hideo Maruyama
Separations 2026, 13(4), 116; https://doi.org/10.3390/separations13040116 - 14 Apr 2026
Viewed by 590
Abstract
Surface-modified waste scallop shells were investigated as a solid flocculant for removing suspended particles, and a light transmission method was examined as a simple approach for evaluating flocculation behavior. Kaolin suspensions (3, 5, 10 g/L, pH 6.95–7.05) were used as model wastewater. Temporal [...] Read more.
Surface-modified waste scallop shells were investigated as a solid flocculant for removing suspended particles, and a light transmission method was examined as a simple approach for evaluating flocculation behavior. Kaolin suspensions (3, 5, 10 g/L, pH 6.95–7.05) were used as model wastewater. Temporal changes in transmitted light intensity were monitored using a white LED–sensor optical system after agitation of the suspension was stopped. The transmitted light intensity, I, was normalized by the intensity measured for particle-free water (I0), and an optical extinction index, A = −log10(I/I0), was used to describe the attenuation of light in the suspension. An apparent clarification rate (rate of change in optical extinction), v, was defined from the initial decrease in the optical extinction index and used as an operational kinetic parameter for comparing flocculation behavior under identical conditions. The results showed that the surface-modified scallop shell particles exhibited measurable flocculation activity toward kaolin suspensions, although the performance was lower than that of commercial polymer flocculants. The optical transmission method enabled continuous monitoring of the flocculation process and provided a practical index for comparing the flocculation performance of different materials. Full article
(This article belongs to the Section Separation Engineering)
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22 pages, 3350 KB  
Article
Toward Mechanism-Driven Control: A Soft-Sensor for Zeta Potential and Settling-Decisive Parameters in Coal Slime Water Treatment
by Jing Chang, Bianbian Guo, Guoyu Bai, Xinyuan Zhang, Hang Zhang, Wei Zhao and Zhen Li
Separations 2026, 13(4), 115; https://doi.org/10.3390/separations13040115 - 13 Apr 2026
Viewed by 525
Abstract
Intelligent dosing in coal slime water treatment remains a challenge due to the lack of real-time and solid hardware-based measurement of key microscopic parameters governing the settling process, particularly zeta potential. This study proposes a soft-sensor method using Sparrow Search Algorithm-optimized Extreme Learning [...] Read more.
Intelligent dosing in coal slime water treatment remains a challenge due to the lack of real-time and solid hardware-based measurement of key microscopic parameters governing the settling process, particularly zeta potential. This study proposes a soft-sensor method using Sparrow Search Algorithm-optimized Extreme Learning Machine (SSA-ELM) to simultaneously predict four critical settling process parameters: settling velocity, supernatant turbidity, sediment layer height, and zeta potential. Key variables influencing the coal slime water settling process, including coal slime water concentration, fines content, water hardness, pH, and chemical dosage, were investigated, and the experimental data were used as inputs for the development of the prediction model. The prediction performance of the proposed SSA-ELM model was evaluated against standard ELM and SSA-optimized Back Propagation (BP) models. The results demonstrate that the SSA-ELM model achieved superior prediction accuracy for all parameters, with R2 values ranging from 0.95 to 0.98, while maintaining favorable computational efficiency. This study establishes a method for virtual measurement of zeta potential, providing a crucial data foundation for developing mechanism-driven, intelligent dosing systems aimed at precise intelligent control and reduced chemical consumption for coal preparation plants. Full article
(This article belongs to the Special Issue Separation Techniques for Wastewater Treatment)
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19 pages, 3188 KB  
Article
Optimisation, Component Analysis, and Bioactivity Evaluation of Sunflower Calathide Flavonoids Obtained Using Ultra-High-Pressure Extraction
by Haoqian Yan, Guifeng Zhang and Li Ma
Separations 2026, 13(4), 114; https://doi.org/10.3390/separations13040114 - 9 Apr 2026
Viewed by 574
Abstract
This study aims to achieve the efficient preparation of sunflower calathide flavonoids (SCF) through optimized processes and to elucidate their composition and bioactivity. Total flavonoids were prepared by optimizing the ultra-high-pressure extraction (UHPE) process using a combination of single-factor experiments and response surface [...] Read more.
This study aims to achieve the efficient preparation of sunflower calathide flavonoids (SCF) through optimized processes and to elucidate their composition and bioactivity. Total flavonoids were prepared by optimizing the ultra-high-pressure extraction (UHPE) process using a combination of single-factor experiments and response surface methodology, followed by purification and enrichment via macroporous resin. The components were identified with UPLC-QTOF-MS/MS technology, and their antioxidant activity and inhibitory capacity against xanthine oxidase (XOD) were systematically evaluated. The optimal extraction conditions were determined as follows: an extraction pressure of 290 MPa, a holding time of 8 min, an ethanol concentration of 67%, and a solid-to-liquid ratio of 1:14 g/mL. Under these conditions, the total flavonoid extraction yield reached 13.52 mg/g, which was further enriched to 16.74 mg/g after purification by macroporous resin. A total of 32 flavonoid compounds were identified, and the purified extract exhibited stronger free radical scavenging ability, total reducing power, ferric ion reducing activity, and XOD inhibitory effect compared to the unpurified extract. The combination of UHPE with macroporous resin separation technology effectively enriches SCF, and the resulting extract possesses both antioxidant and xanthine oxidase inhibitory activities, providing a theoretical basis and technical support for its industrial production and application. Full article
(This article belongs to the Special Issue Extraction, Purification and Functional Substances of Natural Products and Plants)
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14 pages, 4038 KB  
Article
Mechanical Model and Kinematic Characteristics of the Particle Impacting Screen Plate During Flip-Flow Screening Process
by Weinan Wang, Xu Hou, Jiahao Pan, Wei Shi and Xiaolu Ye
Separations 2026, 13(4), 113; https://doi.org/10.3390/separations13040113 - 5 Apr 2026
Viewed by 447
Abstract
Flip-flow screens are widely used for the efficient separations of wet fine materials. To explore the separation characteristics of the particle and screen plate in the flip-flow screening process, a flip-flow plate impact experimental system was built. The experimental system was based on [...] Read more.
Flip-flow screens are widely used for the efficient separations of wet fine materials. To explore the separation characteristics of the particle and screen plate in the flip-flow screening process, a flip-flow plate impact experimental system was built. The experimental system was based on a spherical inertial measurement device and a semi-industrial flip-flow screen system. In this study, we first derive the impact mechanics equation of the flip-flow screen plate on the particle and analyze the influence of the main parameters on the maximum impact force. Subsequently, we investigated the kinematic characteristics of the particle impacted by the screen plate at different moving positions, the variation of the centerline acceleration mechanism, and determined the angular velocity in the collision process. Additionally, we further clarified the alteration in the rules of translational and rotational kinetic energy of the particles in the collision process. This study addresses a research gap in the phenomenological modelling of particulate screening process. At the same time, it provides theoretical support for the accurate control of the flip-flow screening process. Full article
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19 pages, 7326 KB  
Article
Upcycling Coal Gangue and Phosphate Tailings into Layered Double Hydroxides for Simultaneous Remediation of Cr (VI), Cd (II) and Ni (II) in Contaminated Soils
by Qinhan Ye, Pei Zhao, Xuan Xia, Yang Xiao and Xinhong Qiu
Separations 2026, 13(4), 112; https://doi.org/10.3390/separations13040112 - 4 Apr 2026
Viewed by 566
Abstract
Two mineral-based solid residues, namely coal gangue (CG) and phosphorus tailings (PT), two of the largest solid waste streams in the mining industry, were used as the sole metal feedstocks to fabricate a novel MgCaFeAl layered double hydroxide (LDH-GT) via a 700 °C [...] Read more.
Two mineral-based solid residues, namely coal gangue (CG) and phosphorus tailings (PT), two of the largest solid waste streams in the mining industry, were used as the sole metal feedstocks to fabricate a novel MgCaFeAl layered double hydroxide (LDH-GT) via a 700 °C calcination, acid leaching and hydrothermal coprecipitation route, with simultaneous synthesis of white carbon black from the reaction byproducts. Under optimized conditions (total metal load is 150 mg kg−1, LDH-GT dose is 0.09 g, pH from 6 to 7), the synthesized material achieved concurrent immobilization efficiencies of 76.28%, 99.96%, and 99.95% for Cr (VI), Cd (II) and Ni (II), respectively, within a 24 h reaction period. TCLP leachability decreased by 82 to 91% relative to the untreated soil. After three wetting, drying and freeze–thaw cycles, the leached concentrations of all three metals remained below 0.3 mg L−1, confirming excellent long-term stability. Mechanistic analyses revealed that Cr (VI) was mainly sequestered through interlayer anion exchange and surface complexation, whereas Cd (II) and Ni (II) were immobilized via isomorphic substitution into the LDH lattice, precipitation as carbonates, and incorporation into Fe/Mn oxides. A 7-day mung bean bioassay showed that LDH-GT amendment increased seed germination from 50% to 73%, enhanced root and shoot biomass by 1.1- to 1.6-fold, and decreased plant Cr, Cd, and Ni contents by over 80%. The 16S rRNA sequencing further demonstrated that LDH-GT reversed the decline in microbial α diversity induced by heavy metal stress, restored aerobic chemoheterotrophic and sulfur cycling functional guilds, and reduced pathogenic signatures. This study provides the demonstration of a waste-to-resource LDH that achieves efficient, durable remediation of multi-metal-contaminated soils, offering a scalable route for coupling solid waste valorization with in situ site restoration. Full article
(This article belongs to the Special Issue Separation Technology for Metal Extraction and Removal)
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26 pages, 4520 KB  
Article
Effects of Cone Segment Configuration on the Classification Performance of Hydrocyclones
by Xiaoxiao Cai and Hao Lu
Separations 2026, 13(4), 111; https://doi.org/10.3390/separations13040111 - 3 Apr 2026
Viewed by 658
Abstract
As an efficient solid–liquid separation device, the hydrocyclone is widely applied in various industrial fields such as coal preparation and oil impurity removal, and its classification performance directly determines the efficiency of industrial separation operations., As the core separation zone of the hydrocyclone, [...] Read more.
As an efficient solid–liquid separation device, the hydrocyclone is widely applied in various industrial fields such as coal preparation and oil impurity removal, and its classification performance directly determines the efficiency of industrial separation operations., As the core separation zone of the hydrocyclone, the cone segment, its structure and the number of cone angles directly affect the flow field distribution characteristics and particle classification performance of the hydrocyclone. To reveal the regulation mechanism of the combined cone angles on the classification performance of hydrocyclones, numerical analysis and experimental verification methods were adopted to investigate the internal flow field and classification performance of hydrocyclones under different cone angle combinations. The evolution laws of velocity field, pressure field, turbulence characteristics, and particle classification effect under different configurations were systematically explored. The results show that the basic characteristics of the core flow field of the hydrocyclone do not change essentially with the increase in the number of cone segments, but the amplitude, distribution, and stability of flow field parameters are significantly regulated. The three-cone configuration achieves the optimal flow field synergy effect: the amplitude of the high turbulence intensity zone is lower and concentrated near the central axis; the zero-velocity envelope surface is stably maintained at approximately 8 mm in the core separation zone; and the full axial fluctuation of the air core is gentle, which effectively inhibits random particle diffusion and flow pattern mixing. In terms of separation performance, the three-cone configuration exhibits the highest classification efficiency in the core range of sub-coarse particles (10~30 μm), with the cut size (approximately 17.5 μm) in a reasonable range, the steepness index reaching a peak value (approximately 0.55), and the pressure drop (approximately 1.8 × 105 Pa) and split ratio (2.8%) achieving synergistic optimization, balancing separation accuracy and energy consumption control. The single-cone configuration causes flow field disturbance due to the one-time contraction of the flow channel, while the four-cone configuration falls into the dilemma of “high pressure drop–marginal performance gain”, and neither achieves optimal performance. The regulation law of the number of cone segments revealed in this study provides a scientific basis for the structural optimization and engineering application of multi-cone hydrocyclones, and is of great significance for improving the particle classification efficiency in fields such as wastewater treatment and mineral processing. Full article
(This article belongs to the Section Separation Engineering)
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20 pages, 8410 KB  
Article
Comprehensive Discovery and Characterization of Chemical Constituents in Huangqintang Decoction Using Off-Line Two-Dimensional Liquid Chromatography and High-Resolution Mass Spectrometry
by Yan Fang, Yi Nan, Xijie Tian, Junyu Zhang, Xiaojuan Chen, Juan Song, Haizhen Liang and Baiping Ma
Separations 2026, 13(4), 110; https://doi.org/10.3390/separations13040110 - 1 Apr 2026
Viewed by 547
Abstract
Traditional Chinese prescriptions are characterized by complex chemical constituents and wide variations in constituent content, which pose a substantial challenge to their comprehensive characterization. As a classic traditional Chinese prescription known for its heat-clearing and detoxifying properties, Huangqintang Decoction (HQD) is composed of [...] Read more.
Traditional Chinese prescriptions are characterized by complex chemical constituents and wide variations in constituent content, which pose a substantial challenge to their comprehensive characterization. As a classic traditional Chinese prescription known for its heat-clearing and detoxifying properties, Huangqintang Decoction (HQD) is composed of Scutellariae Radix, Paeoniae Radix Rubra, Glycyrrhizae Radix et Rhizoma, and Jujubae Fructus. In this study, we developed an off-line two-dimensional liquid chromatography that addressed the limitations of traditional analysis of unfractionated extracts, such as restricted peak capacity, which often obscured trace components. By coupling with ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS), this study successfully performed rapid identification or characterization of the complete chemical profile of HQD. Notably, beyond high-throughput identification, this approach leveraged characteristic fragment ions and reversed-phase chromatographic behaviors to differentiate some isomers of flavonoid glycosides and triterpenoid saponins, demonstrating its depth in structural identification. Flavonoid glycoside isomers were distinguished by diagnostic neutral losses, while flavanones and chalcones were characterized by retro-Diels–Alder (RDA) and β-rearrangement, respectively. Isomers of triterpenoid saponins were inferred from aglycone-specific pathways alongside RDA cleavages. Ultimately, a total of 192 compounds were identified, including 88 flavonoids, 80 triterpenoids, 7 monoterpene glycosides, 3 fatty acid amides, 3 phenylethanoid glycosides, 4 coumarins, 3 saccharides, 1 organic acid, and 3 others. This study demonstrated that the off-line two-dimensional liquid chromatography analysis strategy significantly enhanced chromatographic resolution and expanded the coverage of trace components. It presented an effective strategy for comprehensive compound identification in complex traditional Chinese medicine prescriptions. Full article
(This article belongs to the Topic Application of Chromatography-Mass Spectrometry and Related Techniques, 2nd Edition)
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14 pages, 2151 KB  
Article
Selective HCl Separation from HCl/SiF4 Mixtures via Glycerol-Based Absorption and Staged Vacuum Desorption
by Panpan Chu, Qihan Wang, Fan Yang, Guangpeng Chen, Wangzhiyuan He, Hao Pan, Liting Fan, Xiaojian Yang, Jinpeng Shi and Shaolong Wan
Separations 2026, 13(4), 109; https://doi.org/10.3390/separations13040109 - 31 Mar 2026
Viewed by 824
Abstract
The selective removal of HCl from industrial HCl/SiF4 mixtures was investigated using a series of alcohol-based and deep eutectic solvents (DESs). Among them, glycerol (GL) exhibited superior selectivity for HCl despite a moderate total capacity. Absorption at 60 °C ensured stable operation [...] Read more.
The selective removal of HCl from industrial HCl/SiF4 mixtures was investigated using a series of alcohol-based and deep eutectic solvents (DESs). Among them, glycerol (GL) exhibited superior selectivity for HCl despite a moderate total capacity. Absorption at 60 °C ensured stable operation with minimal foaming. Desorption analysis revealed that both HCl and SiF4 underwent partial irreversible absorption under N2 stripping, while staged vacuum desorption enabled efficient and selective recovery—SiF4 was fully removed at 70 °C and 6 kPa, followed by nearly complete HCl desorption at 90 °C. Cyclic tests confirmed excellent solvent stability and rapid regeneration, with complete desorption achieved within 10–15 min. A conceptual process was proposed based on these findings, demonstrating a practical and energy-efficient route for selective HCl recovery from acid–gas mixtures. Full article
(This article belongs to the Section Separation Engineering)
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13 pages, 3330 KB  
Article
Integrated High-Purity Sialic Acid Production Process Using Multi-Stage Membrane Filtration Coupled with Resin Adsorption
by Xue Yu, Zihan Zhai, Qiangcheng Zeng, Jiajia Chen, Jiayi Wang, Wei Zhao, Jinling Liang and Guoxiu Han
Separations 2026, 13(4), 108; https://doi.org/10.3390/separations13040108 - 31 Mar 2026
Viewed by 589
Abstract
This study presents a novel, integrated membrane–resin hybrid platform for the high-efficiency purification of N-acetylneuraminic acid (sialic acid, NANA) from complex microbial fermentation broths. By synergistically combining four sequential stages—ceramic microfiltration (50 nm), ultrafiltration (3 kDa), nanofiltration (150 Da), and dual-resin purification (macroporous [...] Read more.
This study presents a novel, integrated membrane–resin hybrid platform for the high-efficiency purification of N-acetylneuraminic acid (sialic acid, NANA) from complex microbial fermentation broths. By synergistically combining four sequential stages—ceramic microfiltration (50 nm), ultrafiltration (3 kDa), nanofiltration (150 Da), and dual-resin purification (macroporous adsorption + cation-exchange)—the process achieves stepwise removal of cells, proteins, pigments, monovalent salts, and divalent metal ions without using organic solvents or high-salt buffers. Critically, each stage demonstrates high target recovery: 76.2% (CM), 67.3% (UF), and 77.5% (NF), with near-quantitative retention (>95%) during resin treatment due to NANA’s low hydrophobicity and electrostatic repulsion at pH 6.8. Following optimised acidification crystallisation (acetic acid dosage = 3 × concentrate volume; sialic acid concentrate concentration = 333.49 g/L), the final product reaches 97.9% purity with a crystalline yield of 78.6%. This scalable, green purification strategy eliminates major bottlenecks in downstream processing and enables industrial-scale production of pharmaceutical-grade sialic acid, with broad applicability to other high-value acidic biomolecules. Full article
(This article belongs to the Special Issue Recognition Materials and Separation Applications)
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29 pages, 1582 KB  
Review
A Review of Research Progress on Intelligent Cyclone–Filtration-Integrated Equipment for High-Suspended-Solids Mine Water Treatment
by Shengbing Xiao and Lixin Li
Separations 2026, 13(4), 107; https://doi.org/10.3390/separations13040107 - 30 Mar 2026
Cited by 1 | Viewed by 1269
Abstract
Mine water treatment remains a long-term challenge due to high suspended solids, wide particle size distributions, and inflow variability, all of which stress solid–liquid separation systems. Hydrocyclones and filtration often fail not from insufficient capacity, but from the inability to handle dynamic influent [...] Read more.
Mine water treatment remains a long-term challenge due to high suspended solids, wide particle size distributions, and inflow variability, all of which stress solid–liquid separation systems. Hydrocyclones and filtration often fail not from insufficient capacity, but from the inability to handle dynamic influent behavior. This review integrates existing studies and reinterprets mine water treatment as a system performance issue, focusing on maintaining operability under fluctuating conditions. Evidence shows that high-solids mine water behaves as a concentrated multiphase flow, where particle interactions and flow changes lead to gradual shifts in separation behavior. For example, hydrocyclone efficiency ranges from 85 to 95%, and pressure drop increases by 0.5–5 kPa/h under continuous operation. Wear, clogging, and flow redistribution develop together, impacting the operational window of integrated treatment units. Key gaps remain in system performance under fluctuating loads and reliable performance under high-solids loading. The complexity of these interactions often leads to significant operational risk and performance variability in real-world conditions. Future research should focus on dynamic control strategies, multi-stage pre-separation, and advanced filtration designs to enhance system performance, long-term stability, and adaptability in real mining environments. Emerging technologies and new system configurations may further improve efficiency and reduce operational failure risks under extreme conditions. Full article
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22 pages, 877 KB  
Article
Recovery of Phenolic Compounds and Proteins from Spent Coffee Grounds Using Eutectic Solvents
by Cristiane Nunes da Silva, Camilla Ribeiro Ferreira, Bernardo Dias Ribeiro and Filipe Smith Buarque
Separations 2026, 13(4), 106; https://doi.org/10.3390/separations13040106 - 28 Mar 2026
Cited by 2 | Viewed by 1341
Abstract
Spent coffee grounds (SCGs) are an abundant agro-industrial residue with high potential as a source of phenolic compounds and proteins. This study evaluated the extraction of these value-added fractions using hydrophilic and hydrophobic eutectic solvents, applied either alone or combined with enzyme-assisted extraction. [...] Read more.
Spent coffee grounds (SCGs) are an abundant agro-industrial residue with high potential as a source of phenolic compounds and proteins. This study evaluated the extraction of these value-added fractions using hydrophilic and hydrophobic eutectic solvents, applied either alone or combined with enzyme-assisted extraction. A total of 31 hydrophobic eutectic solvents (HESs), nine hydrophilic deep eutectic solvents (DESs), and five conventional solvents were screened for phenolic recovery. Extraction performance was strongly formulation-dependent, with hydrophobic systems showing the highest phenolic yields. HES 4 (camphor:oleic acid) was the best-performing solvent, reaching 1279.49 ± 2.31 mg GAE L−1, followed by borneol:oleic acid (1133.92 ± 5.29 mg GAE L−1). Enzyme addition did not enhance phenolic extraction; the highest values under enzymatic conditions were 896.12 ± 4.80 mg GAE L−1 for HES 4 + Cellic® CTec2 and 819.84 ± 2.66 mg GAE L−1 for HES 4 + Viscozyme®. In contrast, protein extraction increased remarkably with enzyme supplementation, particularly with Cellic® CTec2. The highest protein recovery was obtained with HES 4 + Cellic® CTec2 (1608.74 ± 3.32 mg·L−1), compared with 506.37 ± 5.20 mg·L−1 for neat HES 4. In general, neat HESs were more suitable for phenolic recovery, whereas HESs combined with Cellic® CTec2 were more effective for protein extraction. Full article
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13 pages, 788 KB  
Article
Four New Terpenoids from Fufang Yinhua Jiedu Granules and Their Anti-Influenza A Virus Activity
by Xiu Wang, Xiao-Juan Chen, Qing Sun, Juan Song, Hai-Zhen Liang and Bai-Ping Ma
Separations 2026, 13(4), 105; https://doi.org/10.3390/separations13040105 - 26 Mar 2026
Viewed by 713
Abstract
Fufang Yinhua Jiedu Granules (FFYHG) is usually applied to treat influenza and the common cold. However, there is no available report concerning the effects of chemical constituents in FFYHG on antiviral activity. In our study, four new terpenoid derivatives (1–4 [...] Read more.
Fufang Yinhua Jiedu Granules (FFYHG) is usually applied to treat influenza and the common cold. However, there is no available report concerning the effects of chemical constituents in FFYHG on antiviral activity. In our study, four new terpenoid derivatives (1–4) and seventeen known compounds were isolated from FFYHG. Their structures and absolute configurations were determined by various techniques, including high-resolution mass spectrometry analysis, 1/2-dimensional (1D/2D) nuclear magnetic resonance (NMR) analysis, comparative electronic circular dichroism (ECD) studies (experiment vs. calculation), and acid hydrolysis. In addition, the inhibitory effects of twenty-one isolated compounds against influenza A viruses (H1N1) including A/California/07/2009 (CA07) and A/WSN/1933 (WSN) strains were evaluated in vitro, and compound 4 exhibited a moderate inhibitory effect on CA07 strain, with a half maximal inhibitory concentration (IC50) value of 37.10 ± 1.35 μM. This study enhanced the understanding of the active ingredients in FFYHG against influenza virus, providing a foundation for further research on the material basis and quality control of FFYHG. Full article
(This article belongs to the Special Issue Extraction, Purification and Functional Substances of Natural Products and Plants)
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24 pages, 3153 KB  
Article
Removal Performance and Mechanism of Iron–Phosphorus-Based Composite Biochar for Pb(II) and Sb(III) from Water
by Tingting Ren, Hongxiang Zhu, Zongqiang Zhu, Jian Tan and Qiqi Qin
Separations 2026, 13(4), 104; https://doi.org/10.3390/separations13040104 - 25 Mar 2026
Cited by 1 | Viewed by 874
Abstract
In this work, iron–phosphorus-based composite biochar (FPBC) was prepared by modification with the leachate of spent LiFePO4 batteries. The effects of solution pH, dosage, adsorption time, initial concentration, and temperature on the adsorption performance of FPBC were investigated by batch adsorption experiments [...] Read more.
In this work, iron–phosphorus-based composite biochar (FPBC) was prepared by modification with the leachate of spent LiFePO4 batteries. The effects of solution pH, dosage, adsorption time, initial concentration, and temperature on the adsorption performance of FPBC were investigated by batch adsorption experiments with Pb(II) and Sb(III) as the target pollutants, and the adsorption mechanism was explored using SEM, BET, XPS, FTIR and XRD characterization. The results indicated that as the initial pH of the solution increased, the removal efficiency of FPBC for Pb(II) gradually increased, while the removal efficiency for Sb(III) remained largely unchanged. The removal of Pb(II) and Sb(III) by FPBC fitted the pseudo-second-order kinetic model and the three-step intraparticle diffusion model, indicating that their removal was primarily controlled by chemical adsorption. Isothermal adsorption studies revealed that FPBC adsorption of Pb(II) better fitted the Langmuir and D-R models, suggesting a monolayer-dominated adsorption process. In contrast, adsorption of Sb(III) fitted the Langmuir, Freundlich, and Temkin models, suggesting a combination of monolayer and multilayer adsorption characteristics. The maximum adsorption capacities of FPBC for Pb(II) and Sb(III) were 312.54 mg·g−1 and 219.20 mg·g−1 at 30 °C, which were approximately 12.85 and 3.37 times those of commercial corn stalk biochar (BC). Thermodynamic analysis confirmed that the removal of Pb(II) and Sb(III) by FPBC was a spontaneous and endothermic process. In addition, FPBC demonstrated strong selective adsorption of Pb(II) in the binary co-adsorption system of Pb(II) and Sb(III). Mechanism studies indicated that Pb(II) removal primarily occurred through co-precipitation, complexation, ion exchange, and electrostatic adsorption, while Sb(III) was mainly adsorbed by FPBC via redox reactions and complexation. Therefore, this work not only provides a low-cost, high-performance adsorbent for the remediation of water contaminated with Pb(II) and Sb(III), but also opens up new avenues for the resource recovery of the leachate of spent LiFePO4 batteries. Full article
(This article belongs to the Special Issue Environmental Functional Materials for Pollutant Separation and Remediation)
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12 pages, 515 KB  
Article
Schinus terebinthifolia Raddi: Compounds Isolated by Countercurrent Chromatography and Biological Activities
by Mara Junqueira Carneiro, Alexandre Augusto Borghi, Guilherme Perez Pinheiro, Ana Lucia Tasca Gois Ruiz, Daniela Mizobutti, Elaine Minatel, Lisieux Santana Juliao, Svetlana Ignatova, Peter Hewitson and Alexandra Christine Helena Frankland Sawaya
Separations 2026, 13(4), 103; https://doi.org/10.3390/separations13040103 - 25 Mar 2026
Viewed by 1115
Abstract
The chemical composition of natural products is complex and the investigation of bioactivities of compounds of interest demands their isolation. S. terebinthifolia Raddi is a tree belonging to the Anacardiaceae family and is used in Brazilian folk medicine; its fruit (pink peppers) are [...] Read more.
The chemical composition of natural products is complex and the investigation of bioactivities of compounds of interest demands their isolation. S. terebinthifolia Raddi is a tree belonging to the Anacardiaceae family and is used in Brazilian folk medicine; its fruit (pink peppers) are used in cooking and its bark in phytomedicine. Extracts of other parts of this plant contain a plethora of components and merit further studies. Countercurrent chromatography (CCC) is frequently employed with natural products due to the high sample recovery rate. The objective of this work was to determine the best solvent system (SS) to fraction the ethanol extracts of leaves, flowers and fruit of Schinus terebinthifolia by CCC and isolate compounds of interest and elucidate their structures through nuclear magnetic resonance (NMR) and mass spectrometry (MS). In addition, antiproliferative, potential cell regeneration and antioxidant activities of the fractions of interest were evaluated. In the present work, three compounds were isolated; two were identified as anacardic acids [(6-(8′, 11′-heptadecadienyl)-salicylic acid and 6-(8′-heptadecenyl)-salicylic acid], as well as (Z)-masticadienoic acid. These compounds showed antiproliferative and potential cell regeneration activities as well as varying degrees of antioxidant capacity. Although these compounds present potential therapeutic activity, more studies are necessary to confirm their safety. Full article
(This article belongs to the Special Issue Extraction, Purification and Functional Substances of Natural Products and Plants)
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12 pages, 827 KB  
Article
Experimental Analysis of PEGs Separation at Mono–Channel Ceramic Membranes in DEMO Plasma Exhaust Processing
by Luca Farina, Gessica Cortese, Daniela Pietrogiacomi, Maria Cristina Campa and Silvano Tosti
Separations 2026, 13(4), 102; https://doi.org/10.3390/separations13040102 - 24 Mar 2026
Viewed by 694
Abstract
Plasma Enhancement Gases (PEGs) are a set of gaseous elements studied for converting plasma thermal energy and mitigating the heat load on the plasma-facing components of a tokamak fusion power plant. In particular, PEG separation is part of the Plasma Exhaust Processing System [...] Read more.
Plasma Enhancement Gases (PEGs) are a set of gaseous elements studied for converting plasma thermal energy and mitigating the heat load on the plasma-facing components of a tokamak fusion power plant. In particular, PEG separation is part of the Plasma Exhaust Processing System of EU-DEMO. This work addresses issues related to the purification of Deuterium-Tritium fusion fuel, introducing ceramic membranes having a low specific area to process and purify unburned streams throughout the fuel cycle. A commercial microporous mono-channel α-Alumina membrane was considered for the evaluation of its efficacy in separating binary mixtures of H2 with a PEG (Ar and N2), D2, or He. Several tests were carried out, feeding equimolar streams of H2-Ar, H2-N2, D2-Ar, and He-Ar, and the separation factor (SF) of the aforementioned binary mixtures was experimentally assessed. Finally, based on the results from the experimental campaign, the separation factors of several gas mixtures that had not been experimentally investigated were theoretically calculated and proposed. Full article
(This article belongs to the Special Issue Advanced Separation Membranes in Environmental and Energy Fields)
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