Next Issue
Volume 12, November
Previous Issue
Volume 12, September
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.5
2.7
Journals
Separations
Volume 12
Issue 10
share announcement

Separations, Volume 12, Issue 10 (October 2025) – 31 articles

Cover Story (view full-size image): The present study optimizes a targeted chromatographic method coupled to mass spectrometry, employing design of experiments, for the determination of 40 organic micro-contaminants with a wide range of polarities. Chromatographic separation was achieved on a pentafluorophenyl column, and a Face-Centered Design was applied for multivariate optimization. Mobile phase flow and temperature were chosen as the study factors, and retention time and peak width as the responses, as indicators of analytical performance. Two optimized runs (for positive and negative electrospray ionization modes) were obtained, enabling the analysis of all analytes in a total of 29 min. The method showed satisfactory sensitivity, precision and specificity and demonstrated to be suitable for routine monitoring of a broad range of emerging contaminants in seawater. View this paper
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
12 pages, 2836 KB  
Article
A Study on Improving Separation Efficiency Through Weir Curvature Optimization in an FWKO with a Dish-Head Inlet
by Hyun-Su Jeong and Youn-Jea Kim
Separations 2025, 12(10), 287; https://doi.org/10.3390/separations12100287 - 19 Oct 2025
Viewed by 282
Abstract
The Free Water Knock Out (FWKO) vessel is a critical device in the oil sands treatment process, responsible for separating water, oil, and gas. This study investigates the gas–oil interface within the FWKO and analyzes the flow characteristics of the unresolved mixture near [...] Read more.
The Free Water Knock Out (FWKO) vessel is a critical device in the oil sands treatment process, responsible for separating water, oil, and gas. This study investigates the gas–oil interface within the FWKO and analyzes the flow characteristics of the unresolved mixture near the interface. To enhance the separation efficiency by increasing the residence time of the mixture, a concave-shaped weir was introduced. Numerical simulations were conducted using ANSYS Fluent 2023 R1, applying the Volume of Fluid (VOF) model to capture the multiphase flow behavior. Optimization was performed using a genetic algorithm, and the optimal weir curvature with a minor radius of 0.017333 m and a major radius of 0.19032 m yielded the highest separation efficiency. The model incorporating the optimized weir demonstrated a 1.26% improvement in separation efficiency compared to the reference model, and a 2.13% improvement over the baseline model without curvature. These findings confirm that applying curvature to the traditionally flat weir can achieve higher separation efficiency. Moreover, improving separation efficiency through such a simple geometric modification demonstrates significant economic effectiveness. Full article
►▼ Show Figures

Figure 1

22 pages, 2322 KB  
Article
Adsorption of Methylene Blue (MB) Using Novel Synthesized Phosphogypsum Flotation Tailings-Derived Zeolite (PGTZ): Experimental and Modeling Approaches
by Changxin Li, Jinyu Yang, Shanpei Liu, Nan Liu, Lili Zhang and Lu Ren
Separations 2025, 12(10), 286; https://doi.org/10.3390/separations12100286 - 16 Oct 2025
Viewed by 375
Abstract
A phosphogypsum flotation tailings-derived zeolite (PGTZ) was synthesized from the tailings produced during the reverse flotation of phosphogypsum through alkaline fusion and hydrothermal treatment. The response surface methodology (RSM) utilizing a three-level Box–Behnken design (BBD) was used to assess the adsorption of MB [...] Read more.
A phosphogypsum flotation tailings-derived zeolite (PGTZ) was synthesized from the tailings produced during the reverse flotation of phosphogypsum through alkaline fusion and hydrothermal treatment. The response surface methodology (RSM) utilizing a three-level Box–Behnken design (BBD) was used to assess the adsorption of MB by PGTZ. Polynomial regression models were developed to analyze the effects of process parameters on adsorption capacity (qe). The maximum MB adsorption occurred under the following optimized conditions: PGTZ dosage = 5.31 g·L−1; initial MB concentration = 294.59 mg·L−1; pH = 7.42; and adsorption time = 187.89 min. Additionally, adsorption isotherm and kinetic models were fitted to the experimental data to determine model parameters. The Langmuir isotherm model and pseudo-second-order kinetic model incorporating intraparticle diffusion were able to effectively predict MB adsorption onto PGTZ. Thermodynamic analyses indicated that the adsorption process was spontaneous, with strong chemical interactions between MB and PGTZ. Full article
►▼ Show Figures

Figure 1

21 pages, 2824 KB  
Article
Vanadium, Titanium, and Iron Extraction from Titanomagnetite Ore by Salt Roasting and 21st-Century Solvents
by Emmanuel Anuoluwapo Oke, Johannes Hermanus Potgieter, David Nkhoesa and Lizelle Doreen van Dyk
Separations 2025, 12(10), 285; https://doi.org/10.3390/separations12100285 - 15 Oct 2025
Viewed by 487
Abstract
Vanadium is a strategic metal with critical applications in steel alloys, aerospace, chemical catalysis, and energy storage. However, conventional extraction methods such as high-temperature salt roasting are energy-intensive and environmentally challenging. This study investigated the extraction of V, Ti, and Fe from titanomagnetite [...] Read more.
Vanadium is a strategic metal with critical applications in steel alloys, aerospace, chemical catalysis, and energy storage. However, conventional extraction methods such as high-temperature salt roasting are energy-intensive and environmentally challenging. This study investigated the extraction of V, Ti, and Fe from titanomagnetite ore using aqueous solutions of two ionic liquids (IL), 1-butyl-3-imidazolium hydrogen sulphate ([Bmim][HSO4], and 1-butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF6]) as well as two deep eutectic solvents (DESs) (choline chloride:oxalic acid and choline chloride:succinic acid). Na2CO3 and Na2SO4 roasting were used as benchmarks for comparison purposes. Leaching was performed across a range of concentrations and temperatures, and metal recoveries were quantified by atomic absorption spectroscopy (AAS). Among all methods, ChCl:OA DES achieved the best leaching efficiencies of 97.6% for V, 76.1% for Ti, and 68.8% for Fe at 50% (v/v) and 100 °C, outperforming [Bmim][HSO4] and conventional roasting. Kinetic analysis using the shrinking core model indicated that leaching is predominantly diffusion-controlled, with apparent activation energies of 35.1 kJ/mol for V, 28.3 kJ/mol for Ti, and 29.8 kJ/mol for Fe. The results demonstrate that ChCl:OA DES provides a low-temperature, biodegradable, and cost-effective approach for V, Ti and Fe extraction, offering a sustainable alternative to conventional salt roasting methods. Full article
(This article belongs to the Special Issue Advances in Separation and Leaching for Metal Recovery)
►▼ Show Figures

Graphical abstract

19 pages, 2985 KB  
Article
Adsorption of Platinum from Alkaline Glycine–Cyanide Solutions Using Activated Carbon: Leachates, Water, and Waste Treatment Applications
by Caroline Rubina Acuna, Elsayed A. Oraby, G. A. Bezuidenhout, Chau Chun Beh and Jacques J. Eksteen
Separations 2025, 12(10), 284; https://doi.org/10.3390/separations12100284 - 13 Oct 2025
Viewed by 365
Abstract
Platinum’s unique properties, such as its high resistance to corrosion and high temperatures, are driving an increased use in modern technologies and advanced chemistry. However, the World Platinum Investment Council has projected, for the third consecutive year, a global deficit of platinum for [...] Read more.
Platinum’s unique properties, such as its high resistance to corrosion and high temperatures, are driving an increased use in modern technologies and advanced chemistry. However, the World Platinum Investment Council has projected, for the third consecutive year, a global deficit of platinum for 2025 and a negative forecast until 2029, highlighting the need for the development of new metallurgical methodologies to recover platinum but also to recycle product containing it. The use of alkaline amino acid (glycine) promises a highly selective and more environmentally friendly recovery methodology. Over the Platinum Group Metals, recovery studies have been performed only on palladium, but no published literature over platinum was found. This study investigated the feasibility of platinum adsorption from alkaline glycine solutions under various operational conditions using activated carbon. Results are demonstrating that platinum can be successfully recovered under the effects tested: 92.37–97.93% (carbon dosage), 70.00–95.72% (temperature), 94.08–97.39% (pH), 95.16–96.23% (platinum concentration), 95.72–96.53% (glycine concentration), and 95.72–97.12% (cyanide concentration). The scientific significance of this study lies in the confirmation for the potential use of a more environmentally friendly approach to recover platinum as opposed to the current cyanide and acidic chloride system. Full article
(This article belongs to the Special Issue Applications of Adsorbent Materials in Water and Wastewater Treatment)
►▼ Show Figures

Figure 1

28 pages, 1877 KB  
Review
Functionalized Carbon-Based Materials for Uranium Extraction: A Review
by Maqbool Hussain, Liang Zhao, Xusheng Zhang, Chen Yang, Yi Cui, Zhisheng Yu and Jianzhong Zheng
Separations 2025, 12(10), 283; https://doi.org/10.3390/separations12100283 - 13 Oct 2025
Viewed by 550
Abstract
The development of effective materials for uranium extraction from seawater is vital for advancing sustainable energy solutions. However, the efficient recovery of uranium from seawater presents significant challenges due to its extremely low concentration, the presence of competing ions, and the complex marine [...] Read more.
The development of effective materials for uranium extraction from seawater is vital for advancing sustainable energy solutions. However, the efficient recovery of uranium from seawater presents significant challenges due to its extremely low concentration, the presence of competing ions, and the complex marine environment. To address these issues, various materials such as inorganic and organic sorbents, chelating resins, nanostructured sorbents, and composite materials have been explored. More recently, the functionalization of carbon-based materials for enhanced adsorption properties has attracted much interest because of their high specific surface area, excellent chemical and thermal stability, and tunable porosity. These materials include activated carbon, graphene oxide, biochar, carbon cloths, carbon nanotubes, and carbon aerogels. The enhancement of carbonaceous materials is typically achieved through surface functionalization with chelating groups and the synthesis of composite materials that integrate other high-performance sorbents. This review aims to summarize the work of these functionalized carbon materials, focusing on their adsorption capacity, selectivity, and durability for uranium adsorption. This is followed by a discussion on the binding mechanisms of uranium with major chelating functional groups grafted on carbonaceous sorbents. Finally, an outlook for future research is suggested. We hope that this review will be helpful to researchers engaged in related studies. Full article
►▼ Show Figures

Graphical abstract

20 pages, 1440 KB  
Article
Phenolic Compounds in Plant-Based Milk Alternatives from the Greek Market
by Velisaria-Eleni Gerogianni, Christiana Mantzourani, Maria A. Theodoropoulou, Antonia Chiou and Maroula G. Kokotou
Separations 2025, 12(10), 282; https://doi.org/10.3390/separations12100282 - 11 Oct 2025
Viewed by 1074
Abstract
Plant-based milk alternatives (PBMAs) are plant-based fluid products that are marketed as substitutes for regular milk. The nutrient composition of PBMA products can vary widely, depending on the plant source, processing methods, potential additives, etc., and in recent years, considerable research effort has [...] Read more.
Plant-based milk alternatives (PBMAs) are plant-based fluid products that are marketed as substitutes for regular milk. The nutrient composition of PBMA products can vary widely, depending on the plant source, processing methods, potential additives, etc., and in recent years, considerable research effort has been devoted to the exploration of the nutritional content of PBMAs, which are increasingly consumed worldwide. In the present study, an established UHPLC–Orbitrap MS method was employed for the extensive characterization of phenolic compounds in PBMAs available in the Greek market. Twenty-eight PBMAs were studied, including a variety of almond-, soy-, coconut-, oat-, walnut-, and rice-based products. In almond-based milk products, low total concentrations and a broad distribution across compound classes were observed, with trans-chlorogenic acid and neochlorogenic acid being the most abundant constituents, whereas coconut-based milk samples were generally not rich in phenolic compounds. In soy-based milk samples, the presence of isoflavones including daidzein, genistein, and glycitein was uniquely detected, while oat-based products were the samples richer in phenolic content, in particular for hydroxycinnamic acids, such as trans-chlorogenic acid and neochlorogenic acid. In addition, a suspect screening approach, using Exactive Plus Orbitrap, enabled the exploration and semi-quantification of three avenanthramides (A, B, C) in the studied oat-based milk samples and six isoflavonoids, namely daidzein and genistein derivatives, in soy-based milk. Such compounds are known for their antioxidant and anti-inflammatory properties, and their occurrence in PBMAs highlights the potential health-promoting effects of these dairy alternatives. Full article
(This article belongs to the Special Issue Extraction, Purification and Functional Substances of Natural Products and Plants)
►▼ Show Figures

Graphical abstract

12 pages, 2700 KB  
Article
Study on the Emission Characteristics of Fine Particulate Matter in the White Mud Desulfurization Process
by Changqing Wang, Yongchao Feng, Xin Wang, Rongliang Xie, Guanglei Li, Li Yu and Lingxiao Zhan
Separations 2025, 12(10), 281; https://doi.org/10.3390/separations12100281 - 11 Oct 2025
Viewed by 304
Abstract
White mud is a promising desulfurizing agent, but the risk of fine particulate emissions exists during its application. This study investigated the fine particulate emissions in the white mud desulfurization process and analyzed the effects of process parameters, including gas-to-liquid ratio, empty tower [...] Read more.
White mud is a promising desulfurizing agent, but the risk of fine particulate emissions exists during its application. This study investigated the fine particulate emissions in the white mud desulfurization process and analyzed the effects of process parameters, including gas-to-liquid ratio, empty tower gas velocity, and slurry concentration, on particulate emissions. The results showed that white mud desulfurization achieved effective SO2 removal, with a removal efficiency ranging from 93.5% to 95.8%. However, the emission of fine particulates was found to be a significant environmental concern. At a slurry concentration of 15%, the fine particulate number concentration was found to be 5.9 × 106 particles/cm3, with a mass concentration of approximately 43.2 mg/m3. The study further revealed that increasing the empty tower gas velocity from 2.5 m/s to 4.5 m/s also significantly increased particulate emissions. Similarly, increasing the gas-to-liquid ratio from 10 L/m3 to 15 L/m3 led to a 25.5% increase in the fine particulate number concentration. These changes were attributed to the increased atomization of fine droplets and the enhanced gas–liquid relative movement, which facilitated the entrainment of more fine particulates into the flue gas. While improving the slurry concentration led to better desulfurization efficiency, these adjustments also resulted in higher fine particulate emissions. Therefore, optimizing process parameters to balance desulfurization efficiency and fine particulate emission control was crucial for practical applications. Full article
(This article belongs to the Special Issue Application of Advanced Materials and Technologies in the Separation and Adsorption)
►▼ Show Figures

Figure 1

18 pages, 1969 KB  
Review
Artemisia frigida Willd.: Advances in Traditional Uses, Phytochemical Constituents, Extraction and Separation Methods, and Pharmacological Activities
by Wei Tian, Mengjie Zhang, Tongcun Zhang, Xianglong Li, Haiying Zhang and Xiumei Li
Separations 2025, 12(10), 280; https://doi.org/10.3390/separations12100280 - 11 Oct 2025
Viewed by 302
Abstract
Artemisia frigida Willd. (A. frigida), a traditional medicinal herb widely distributed in northern China, Mongolia, and Siberia, has garnered increasing scientific interest due to its diverse phytochemical profile and extensive pharmacological potential. Modern studies have identified a wide range of bioactive [...] Read more.
Artemisia frigida Willd. (A. frigida), a traditional medicinal herb widely distributed in northern China, Mongolia, and Siberia, has garnered increasing scientific interest due to its diverse phytochemical profile and extensive pharmacological potential. Modern studies have identified a wide range of bioactive compounds in A. frigida, including flavonoids, sesquiterpene lactones and phenolic acids. These compounds exhibit various biological activities, such as antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. This review systematically summarizes the research progress on the chemical constituents of A. frigida and their extraction and separation methods, including solvent extraction, ultrasonic-assisted extraction, macroporous resin adsorption, and chromatography-based techniques. By integrating traditional knowledge with modern pharmacological evidence, this review provides a scientific foundation for the further development and utilization of A. frigida in functional food, pharmaceuticals, and ethnomedicine. Full article
(This article belongs to the Special Issue Extraction, Purification and Functional Substances of Natural Products and Plants)
►▼ Show Figures

Graphical abstract

11 pages, 1808 KB  
Article
Ultrasound-Assisted Extraction Optimization and Flash Chromatography Fractionation of Punicalagin from Pomegranate Peel (Punica granatum L.)
by Erick M. Raya-Morquecho, Pedro Aguilar-Zarate, Leonardo Sepúlveda, Mariela R. Michel, Anna Iliná, Cristóbal N. Aguilar and Juan A. Ascacio-Valdés
Separations 2025, 12(10), 279; https://doi.org/10.3390/separations12100279 - 11 Oct 2025
Viewed by 568
Abstract
Background: Pomegranate peel (Punica granatum L.) is a rich source of phenols, particularly ellagitannins, highlighting punicalagin, a bioactive compound with recognized antioxidant potential. However, efficient recovery and purification methods are required to enable its application in food and health-related products. This study [...] Read more.
Background: Pomegranate peel (Punica granatum L.) is a rich source of phenols, particularly ellagitannins, highlighting punicalagin, a bioactive compound with recognized antioxidant potential. However, efficient recovery and purification methods are required to enable its application in food and health-related products. This study aimed to obtain a partially purified fraction of punicalagin from pomegranate peel using optimized extraction and purification strategies. Methods: A Taguchi L9 (3)3 experimental design was employed to optimize ultrasound-assisted extraction, evaluating extraction time (10, 20, 30 min), ethanol concentration (20, 40, 80%), and solid-to-solvent ratio (1:12, 1:14, 1:16). Total polyphenol content was quantified using the Folin–Ciocalteu method. Extracts obtained under optimized conditions were concentrated by rotary evaporation and subjected to semipurification using flash chromatography with Amberlite XAD-16 resin. Subsequently, the fractions were lyophilized and analyzed by HPLC/ESI/MS. Results: The Statistica software determined the optimal conditions for polyphenol extraction (20 min, 40% ethanol, 1:12), with the signal-to-noise (S/N) ratio reaching 88.43 ± 0.66, surpassing the predicted value of 77.42. Flash chromatography yielded four fractions, and HPLC/ESI/MS analysis revealed the presence of ellagitannins in all of them, with fraction number 2 showing the highest relative abundance of punicalagin (89.25%). Conclusions: The combination of ultrasound-assisted extraction and flash chromatography proved effective for obtaining punicalagin-rich fractions from pomegranate peel, supporting its potential for nutraceutical applications. Full article
(This article belongs to the Special Issue Novel Separation Methods for the Analysis of Active and Toxic Components in Food: Second Edition)
►▼ Show Figures

Figure 1

14 pages, 2341 KB  
Article
Application of Bio-Based Activated Carbon from Cocoa Husk Waste for High-Efficiency Adsorption in Water Treatment
by Daniela Angelova, Vesislava Toteva and Georgi Georgiev
Separations 2025, 12(10), 278; https://doi.org/10.3390/separations12100278 - 10 Oct 2025
Viewed by 411
Abstract
This research presents the study of utilizing the cocoa husk biomass waste to obtain active carbon through carbonization method, followed by chemical–thermal activation. The activated carbon (CH) was characterized using BET, SEM–EDX, XPS, and Raman techniques. The obtained material showed a high specific [...] Read more.
This research presents the study of utilizing the cocoa husk biomass waste to obtain active carbon through carbonization method, followed by chemical–thermal activation. The activated carbon (CH) was characterized using BET, SEM–EDX, XPS, and Raman techniques. The obtained material showed a high specific surface area of 1661 m2·g−1, and XPS confirmed the presence of oxygen-containing surface functionalities. The adsorption of reactive dye Drimaren Red K-7B by CH was studied to assess the impact of the initial concentration in water solution, temperature, and contact time. The adsorbent achieved over 90% removal within three minutes at 40 °C. The experimental data for the adsorption of Drimaren Red K-7B using CH showed a good fit with the Dubinin–Radushkevich isotherm and a pseudo-second-order kinetic model. This research offers a promising approach for advancing the circular economy through the obtaining of eco-friendly adsorbents derived from biomass waste, exhibiting high initial adsorption efficiency and rapid uptake kinetics towards reactive dye. Full article
(This article belongs to the Special Issue Application of Adsorption and Separation Technologies in Water Treatment)
►▼ Show Figures

Figure 1

22 pages, 3537 KB  
Article
Enhanced Treatment of Swine Farm Wastewater Using an O3/Fe2+/H2O2 Process: Optimization and Performance Evaluation via Response Surface Methodology
by Hang Yu, Kexin Tang, Jingqi Li, Linxi Dong, Zuo Tong How, Dongming Wu and Rui Qin
Separations 2025, 12(10), 277; https://doi.org/10.3390/separations12100277 - 10 Oct 2025
Viewed by 449
Abstract
Biologically treated swine farm wastewater still contains high levels of refractory organics, humic substances and antibiotic residues, posing environmental risks and limiting opportunities for water reuse. Wastewater treatment by ozonation alone suffers from low mass transfer efficiency and selective oxidation. To overcome these [...] Read more.
Biologically treated swine farm wastewater still contains high levels of refractory organics, humic substances and antibiotic residues, posing environmental risks and limiting opportunities for water reuse. Wastewater treatment by ozonation alone suffers from low mass transfer efficiency and selective oxidation. To overcome these limitations, a catalytic ozonation process (O3/Fe2+/H2O2) was applied and optimized using Response Surface Methodology (RSM) based on single-factor experiments and Central Composite Design (CCD) for advanced swine farm wastewater treatment. The optimal conditions ([O3] = 25.0 mg/L, [Fe2+] = 25.9 mg/L, [H2O2] = 41.1 mg/L) achieved a COD removal of 44.3%, which was 86.8% higher than that of ozonation alone, and increased TOC removal to 29.5%, indicating effective mineralization. Biodegradability (BOD5/COD) of swine farm wastewater effluent increased from 0.01 to 0.34 after the catalytic ozonation treatment. Humic-like and fulvic-like substances were removed by 93.7% and 95.4%, respectively, and antibiotic degradation was significantly accelerated and enhanced. The synergistic process improved ozone utilization efficiency by 33.1% and removed 53.95% of total phosphorus through Fe3+-mediated coprecipitation. These findings demonstrate that with catalytic ozone decomposition and production of hydroxyl radicals, the O3/Fe2+/H2O2 system effectively integrates enhanced ozone utilization efficiency, radical synergy, and simultaneous pollutant removal, providing a cost-effective and technically feasible strategy for advanced swine farm wastewater treatment and safe reuse. Full article
(This article belongs to the Special Issue Advanced Treatment Technologies for Emerging Contaminant Control and Resource Utilization)
►▼ Show Figures

Graphical abstract

18 pages, 2990 KB  
Article
CoFeNi-Layered Double Hydroxide Combined Activation of PMS and Ozone for the Degradation of Rhodamine B in Water
by Xiaohan Zhu, Liang Song and Jia Miao
Separations 2025, 12(10), 276; https://doi.org/10.3390/separations12100276 - 9 Oct 2025
Viewed by 524
Abstract
The development of efficient and sustainable advanced oxidation processes (AOPs) for organic pollutant removal is of great significance for water purification. In this study, a CoFeNi-layered double hydroxide (CoFeNi-LDH) catalyst was synthesized and applied for the simultaneous activation of peroxymonosulfate (PMS) and ozone [...] Read more.
The development of efficient and sustainable advanced oxidation processes (AOPs) for organic pollutant removal is of great significance for water purification. In this study, a CoFeNi-layered double hydroxide (CoFeNi-LDH) catalyst was synthesized and applied for the simultaneous activation of peroxymonosulfate (PMS) and ozone to degrade rhodamine B (RhB) in aqueous solution. The CoFeNi-LDH/PMS/ozone system achieved a remarkable RhB removal efficiency of 95.2 ± 1.2% within 8 min under neutral pH conditions. Systematic parametric studies revealed that synergistic interactions among CoFeNi-LDH, PMS, and ozone contributed to the generation of reactive oxygen species (ROS), primarily sulfate radicals (SO4•−) and singlet oxygen (1O2), as confirmed by EPR and quenching experiments. Density functional theory (DFT) calculations demonstrated that ozone enhanced PMS adsorption and activation at CoFeNi catalytic sites. The catalyst exhibited robust magnetic recyclability and structural stability after repeated use. This work highlights a synergistic catalytic strategy for PMS/ozone activation, offering an effective and environmentally friendly platform for dye wastewater remediation. Full article
(This article belongs to the Special Issue Photocatalytic Oxidation and Advanced Oxidation Processes for Sustainable Water Treatment)
►▼ Show Figures

Figure 1

10 pages, 937 KB  
Article
Investigation of Ethanol and Isopropanol as Greener Alternatives to Acetonitrile in the RP-HPLC Purification of Histone Tail Peptides Bearing Acylation-Type Post-Translational Modifications
by Yordan Hayat and Zeynep Kanlidere
Separations 2025, 12(10), 275; https://doi.org/10.3390/separations12100275 - 9 Oct 2025
Viewed by 504
Abstract
Background: Histone post-translational modifications (PTMs) play a pivotal role in the regulation of chromatin structure and gene expression, making them key targets in structural and epigenetic research. Synthetic histone peptides bearing specific PTMs are essential tools for elucidating the molecular mechanisms of histone [...] Read more.
Background: Histone post-translational modifications (PTMs) play a pivotal role in the regulation of chromatin structure and gene expression, making them key targets in structural and epigenetic research. Synthetic histone peptides bearing specific PTMs are essential tools for elucidating the molecular mechanisms of histone function and protein–histone interactions. Methods: We synthesized histone H4 tail peptides containing site-specific lysine modifications using solid-phase peptide synthesis (SPPS). The correct synthesis of the peptides was confirmed by their molecular weights using a mass spectrometer. Results: An improved high-performance liquid chromatography (HPLC) method was developed to efficiently separate peptides with one modification difference. In alignment with green chemistry principles, we evaluated ethanol and isopropanol as an alternative organic solvent to acetonitrile in the mobile phase. The optimized HPLC method using acetonitrile enabled effective resolution of closely related peptide species, providing peptides suitable for downstream applications requiring high purities such as structural biology. Conclusions: This study presents a strategy for the purification of histone PTM peptides, emphasizing both analytical performance and sustainability. Further investigation must be undergone to develop high-precision purification using green chemicals. Full article
►▼ Show Figures

Graphical abstract

20 pages, 6043 KB  
Article
Process Design and Optimisation Analysis for the Production of Ultra-High-Purity Phosphine
by Jingang Wang, Yu Liu, Jinyu Guo, Shuyue Zhou, Yawei Du and Xuejiao Tang
Separations 2025, 12(10), 274; https://doi.org/10.3390/separations12100274 - 9 Oct 2025
Viewed by 439
Abstract
With the increasing demand to scale the chip industry, attention is turning to the vital role that phosphanes and silanes play in semiconductor manufacturing processes such as chemical vapor deposition, plasma etching, and impurity doping. High-performance semiconductors often require a supply of ultra-pure [...] Read more.
With the increasing demand to scale the chip industry, attention is turning to the vital role that phosphanes and silanes play in semiconductor manufacturing processes such as chemical vapor deposition, plasma etching, and impurity doping. High-performance semiconductors often require a supply of ultra-pure gaseous phosphine (≥99.999%) to ensure the formation of defect-free thin-film structures with high integrity and strong functionality. In recent years, research on high-purity PH3 synthesis methods has mainly focused on two pathways: the acidic route with fewer side reactions, high by-product economics, and higher exergy of high-purity PH3, and the alkaline alternative with greater potential for practical application through lower reaction temperatures and a simpler reaction process. This paper presents the first comparative study and analysis on the preparation of ultra-high-purity PH3 and its process energy consumption. Using Aspen and its related software, the energy consumption and cost issues are discussed, and the process heat exchange network is established and optimised. By combining Aspen Plus V14 with MATLAB 2023, an artificial neural network (ANN) prediction model is established, and the parameters of the distillation section equipment are optimised through the NSGA-II model to solve problems such as low product yield and large equipment exergy loss. After optimisation, it can be found that in terms of energy consumption and cost indicators, the acidic process has greater advantages in large-scale production of high-purity PH3. The total energy consumption of the acidic process is 1.6 × 108 kJ/h, which is only one-third that of the alkaline process, while the cost of the heat exchange equipment is approximately three-quarters that of the alkaline process. Through dual-objective optimisation, the exergy loss of the acidic distillation part can be reduced by 1714.1 kW, and the economic cost can be reduced by USD 3673. Therefore, from the perspective of energy usage and equipment manufacturing, the comprehensive analysis of the acidic process has more advantages than that of the alkaline process. Full article
(This article belongs to the Special Issue New Approaches to Phosphorus Pollutant Control and Phosphorus Recovery)
►▼ Show Figures

Figure 1

16 pages, 2595 KB  
Article
Vapor Liquid Equilibrium Measurement and Distillation Simulation for Azeotropic Distillation Separation of H2O/EM Azeotrope
by Chunli Li, Jinxin Zhang, Jiqing Rao, Kaile Shi, Yuze Sun, Wen Liu and Jiapeng Liu
Separations 2025, 12(10), 273; https://doi.org/10.3390/separations12100273 - 8 Oct 2025
Viewed by 824
Abstract
Since H2O and Ethylene Glycol Monomethyl Ether (EM) form a minimum-boiling azeotrope, 1-pentanol, 1-hexanol, and 1-heptanol are selected as entrainers to separate the azeotropic mixture (H2O/EM) using azeotropic distillation. The binary vapor liquid equilibrium (VLE) data were determined at [...] Read more.
Since H2O and Ethylene Glycol Monomethyl Ether (EM) form a minimum-boiling azeotrope, 1-pentanol, 1-hexanol, and 1-heptanol are selected as entrainers to separate the azeotropic mixture (H2O/EM) using azeotropic distillation. The binary vapor liquid equilibrium (VLE) data were determined at 101.3 kPa, including H2O/EM, EM/1-pentanol, EM/1-hexanol, EM/1-heptanol, H2O/1-pentanol, H2O/1-hexanol and H2O/1-heptanol. Meanwhile, the Herington area test was used to validate the thermodynamic consistency of the experimental binary data. The VLE data for the experimental binary system were analyzed using the NRTL, UNIQUAC, and Wilson activity coefficient models, showing excellent agreement between predictions and measurements. Finally, molecular simulations were employed to calculate interaction energies between components, providing insights into the VLE behavior. The azeotropic distillation process was simulated using Aspen Plus to evaluate the separation performance and determine the optimal operating parameters. Therefore, this study provides guidance and a foundational basis for the separation of H2O/EM systems at 101.3 kPa. Full article
(This article belongs to the Special Issue Green Separation and Purification Technology)
►▼ Show Figures

Figure 1

12 pages, 3054 KB  
Article
The Influence of Y2O3 Nanoparticles on the Permeation Properties of Polyethersulfone Membranes
by Andreea Liliana Lazăr, Adrian Cîrciumaru, Gina Genoveva Istrate, Eliza Dănăilă and Ștefan Baltă
Separations 2025, 12(10), 272; https://doi.org/10.3390/separations12100272 - 7 Oct 2025
Viewed by 317
Abstract
Y2O3 nanoparticles were used in a polyethersulfone (PES) as additives to increase the permeation properties of the polymeric membranes. Membranes were manufactured by diffusion-induced phase inversion in N-methyl-pyrrolidone (NMP) using a different concentration of nanoparticles. Y2O3 is [...] Read more.
Y2O3 nanoparticles were used in a polyethersulfone (PES) as additives to increase the permeation properties of the polymeric membranes. Membranes were manufactured by diffusion-induced phase inversion in N-methyl-pyrrolidone (NMP) using a different concentration of nanoparticles. Y2O3 is used in polymeric membranes to enhance their functional properties, especially in wastewater treatment processes. Incorporating Y2O3 nanoparticles into the polymer matrix improves the membrane’s hydrophilicity, permeability, and mechanical strength. Additionally, Y2O3 provides better properties and reduces fouling. Recent studies highlight its potential as a modifying agent for advanced composite membranes. This paper investigated challenges in the synthesis of Y2O3-enhanced membranes and links synthesis with performance. It was observed that the composite membranes have better permeation properties by adding a small amount of Y2O3. For membranes at 21 wt.% PES permeability increase from 107 to 112 L/m2·h/bar. Fouling performance increases by adding nanoparticles, relative flux decreases by 30% for membranes without nanoparticles and by 10% for membranes with nanoparticles, both at a concentration of 25% PES. Rejection increases for membranes at 21%Pes from 21% for membranes without nanoparticles to 39% for membranes with nanoparticles. The influence of Y2O3 nanoparticles on the membranes’ performance was determined by filtration experiments to establish the permeability, fouling, retention, and the water flux; by contact angle to establish the surface hydrophilicity; and by SEM to investigate the membranes’ structures. Full article
►▼ Show Figures

Figure 1

16 pages, 1878 KB  
Article
Nitrous Oxide Emission from a Single-Stage Oxygen-Limited Mainstream Anammox Reactor Treating Moderate C/N Ratio Sewage
by Da Di, Xiwei Cao and Xin Zhou
Separations 2025, 12(10), 271; https://doi.org/10.3390/separations12100271 - 7 Oct 2025
Viewed by 429
Abstract
Nitrous oxide (N2O), a potent greenhouse gas, is an important environmental concern associated with biological nitrogen removal in wastewater treatment plants. Anaerobic ammonium oxidation (anammox), recognized as an advanced carbon-neutral nitrogen removal technology, requires a continuous supply of nitrite, which also [...] Read more.
Nitrous oxide (N2O), a potent greenhouse gas, is an important environmental concern associated with biological nitrogen removal in wastewater treatment plants. Anaerobic ammonium oxidation (anammox), recognized as an advanced carbon-neutral nitrogen removal technology, requires a continuous supply of nitrite, which also serves as a key precursor for N2O generation. However, the regulation of the carbon-to-nitrogen (C/N) ratio to minimize N2O emission in mainstream anammox systems remains insufficiently understood. In this study, we evaluated the long-term nitrogen removal performance and N2O emission potential of an oxygen-limited anammox biofilm reactor treating synthetic municipal wastewater with a typical C/N range of 4.0–6.0. Experimental results demonstrated that the highest nitrogen removal efficiency (95.3%), achieved through coupled anammox and denitrification, and the lowest N2O emission factor (0.73%) occurred at a C/N ratio of 5.0. As the C/N ratio increased from 4.0 to 5.0, N2O emissions decreased progressively, but rose slightly when the ratio was further increased to 6.0. High-throughput sequencing revealed that microbial community composition and the abundance of key functional taxa were significantly influenced by the C/N ratio. At a C/N ratio of 5.0, proliferation of anammox bacteria and the disappearance of Acinetobacter populations appeared to contribute to the significant reduction in N2O emission. Furthermore, gene annotation analysis indicated higher abundances of anammox-associated genes (hzs, hdh) and N2O reductase gene (nosZ) at this ratio compared with others. Overall, this study identifies a C/N-dependent strategy for mitigating N2O emissions in mainstream anammox systems and provides new insights into advancing carbon-neutral wastewater treatment. Full article
(This article belongs to the Special Issue Sustainable Biological Removal and Separation Processes in Wastewater Treatment)
►▼ Show Figures

Figure 1

17 pages, 3863 KB  
Article
Adsorption of Cr(III) by IRA-900 Resin in Sodium Phosphite and Sulfuric Acid System
by Tingjie Xu, Dahuan Gan, Guowang Wei, Yingjie Yang, Qiankun Wei and Chunlin He
Separations 2025, 12(10), 270; https://doi.org/10.3390/separations12100270 - 5 Oct 2025
Viewed by 403
Abstract
Chromium (Cr), a toxic heavy metal, poses significant environmental and health risks when industrial effluents containing Cr are discharged untreated. Addressing this challenge, this study developed a selective chromium removal strategy using IRA-900 resin in a sulfuric acid system with sodium phosphite (NaH [...] Read more.
Chromium (Cr), a toxic heavy metal, poses significant environmental and health risks when industrial effluents containing Cr are discharged untreated. Addressing this challenge, this study developed a selective chromium removal strategy using IRA-900 resin in a sulfuric acid system with sodium phosphite (NaH2PO3) as a complexing agent. In the NaH2PO3-H2SO4 system, IRA-900 resin exhibited exceptional selectivity for Cr3+ with minimal co-adsorption of competing ions. The adsorption process followed the Langmuir isotherm model (R2 > 0.99), indicating monolayer chemisorption dominated by homogeneous active sites, and achieved a maximum capacity of 103.56 mg·g−1. Characterization via XPS, FT-IR, and SEM-EDS revealed a two-step mechanism: Cr3+ reacts with H2PO3− to form an anionic complex, and then the complex undergoes electrostatic interaction and ion exchange with chloride ions (Cl−) on the quaternary ammonium groups of the resin. The chromium-loaded resin demonstrated remarkable structural stability, resisting Cr3+ desorption under conventional elution conditions. This property provides a novel pathway for chromium solidification in industrial wastewater, effectively minimizing secondary pollution risks. This work advances the design of ligand-assisted ion-exchange systems for targeted heavy metal removal, offering both high selectivity and environmental compatibility in wastewater treatment. Full article
(This article belongs to the Topic Advances in Separation Engineering)
►▼ Show Figures

Figure 1

23 pages, 6833 KB  
Article
Ultrasound-Assisted Deep Eutectic Solvent Extraction of Flavonoids from Cercis chinensis Seeds: Optimization, Kinetics and Antioxidant Activity
by Penghua Shu, Shuxian Fan, Simin Liu, Yu Meng, Na Wang, Shoujie Guo, Hao Yin, Di Hu, Xinfeng Fan, Si Chen, Jiaqi He, Tingting Guo, Wenhao Zou, Lin Zhang, Xialan Wei and Jihong Huang
Separations 2025, 12(10), 269; https://doi.org/10.3390/separations12100269 - 2 Oct 2025
Viewed by 405
Abstract
This study establishes an efficient and eco-friendly ultrasound-assisted extraction (UAE) method for total flavonoids present in Cercis chinensis seeds using natural deep eutectic solvents (NADES). Among nine NADES formulations screened, choline chloride–levulinic acid (ChCl–Lev, 1:2) demonstrated optimal performance, yielding 112.1 mg/g total flavonoids. [...] Read more.
This study establishes an efficient and eco-friendly ultrasound-assisted extraction (UAE) method for total flavonoids present in Cercis chinensis seeds using natural deep eutectic solvents (NADES). Among nine NADES formulations screened, choline chloride–levulinic acid (ChCl–Lev, 1:2) demonstrated optimal performance, yielding 112.1 mg/g total flavonoids. Through Response Surface Methodology (RSM), the ultrasound-assisted extraction (UAE) parameters were explored. Under the optimized conditions (water content of 30%, time of 28 min, temperature of 60 °C, and solvent-to-solid ratio of 1:25 g/mL), the total flavonoid yield reached 128.5 mg/g, representing a 195% improvement compared to conventional ethanol extraction. The recyclability of NADES was successfully achieved via AB-8 macroporous resin, retaining 80.89% efficiency after three cycles. Extraction kinetics, modeled using Fick’s second law, confirmed that the rate constant (k) increased with temperature, highlighting temperature-dependent diffusivity as a key driver of efficiency. The extracted flavonoids exhibited potent antioxidant activity, with IC50 values of 0.86 mg/mL (ABTS•+) and 0.69 mg/mL (PTIO•). This work presents a sustainable NADES-UAE platform for flavonoid recovery and offers comprehensive mechanistic and practical insights for green extraction of plant bioactives. Full article
(This article belongs to the Special Issue Extraction, Purification and Functional Substances of Natural Products and Plants)
►▼ Show Figures

Figure 1

14 pages, 264 KB  
Article
Variations in Quantitative Composition of Phenolic Compounds in Flowers, Leaves, and Fruits of Mespilus germanica L. During Harvesting Period
by Jelena Nikolić, Vesna Stankov Jovanović, Jovana Pavlović, Milica D. Nikolić, Ana Barjaktarević, Ksenija Obradović and Milan Mitić
Separations 2025, 12(10), 268; https://doi.org/10.3390/separations12100268 - 1 Oct 2025
Viewed by 505
Abstract
The medlar (Mespilus germanica) is a deciduous tree that belongs to the Rosaceae family. This plant has been valued throughout history for its culinary uses and medicinal applications. Medlar fruit contains a high amount of vitamin C, carbohydrates, and pectin, making [...] Read more.
The medlar (Mespilus germanica) is a deciduous tree that belongs to the Rosaceae family. This plant has been valued throughout history for its culinary uses and medicinal applications. Medlar fruit contains a high amount of vitamin C, carbohydrates, and pectin, making it a valuable remedy for treating scurvy. In folk medicine, medlar is used to treat constipation and other digestive issues. This study investigates the quantitative composition and seasonal variation in phenolic compounds in flowers, leaves, and fruits of Mespilus germanica L. using high performance liquid chromatography, as well as total phenolic content and antioxidant activity. The predominant class of phenolics in flowers were flavonols, with 52.5% of the total phenolic content. On the other hand, dominant phenolics in fruits were flavan-3-ols, with procyanidin B2 and epicatechin being most abundant, whereas in leaves, hydroxycinnamic acids were the most prevalent phenolic compounds. Seasonal variations were noted for analyzed compounds in various plant parts. This study highlights significant changes in the phenolic profile of M. germanica during various harvesting periods and suggests that both fruits and leaves are rich sources of bioactive compounds. However, its nutraceutical potential might depend on harvesting time. Full article
(This article belongs to the Special Issue Application of Chromatography in Bioactive Compound Analysis)
20 pages, 3112 KB  
Article
Porous Imprinted Microspheres with Covalent Organic Framework-Based, Precisely Designed Sites for the Specific Adsorption of Flavonoids
by Jinyu Li, Xuan Zhang, Jincheng Xu, Xi Feng and Shucheng Liu
Separations 2025, 12(10), 267; https://doi.org/10.3390/separations12100267 - 1 Oct 2025
Viewed by 332
Abstract
The application of microsphere molecularly imprinted materials for the targeted extraction and purification of flavonoids derived from agricultural waste has emerged as a prominent area of investigation. An innovative boronate affinity imprinted microsphere (MC-CD@BA-MIP) was successfully synthesized using the Pickering emulsion interfacial assembly [...] Read more.
The application of microsphere molecularly imprinted materials for the targeted extraction and purification of flavonoids derived from agricultural waste has emerged as a prominent area of investigation. An innovative boronate affinity imprinted microsphere (MC-CD@BA-MIP) was successfully synthesized using the Pickering emulsion interfacial assembly strategy for the selective separation of naringin (NRG). The double-bond functionalized covalent organic framework (COF)-based microspheres were synthesized through Schiff–base reaction and secondary interfacial emulsion polymerization. Then, the synthetic mono-(6-mercapto-6-deoxy)-β-cyclodextrin (SH-β-CD) was grafted onto the surface of the microspheres (MC) using click chemistry. The 1-allylpyridine-3-boronic acid (APBA) as a functional monomer was grafted onto the initiator (ABIB) through atom transfer radical polymerization (ATRP). Ultimately, the synthesized boronic acid-imprinted ABIB-BA-MIPs were immobilized onto the COFs microsphere surface through host–guest interactions. As expected, under neutral conditions, the MC-CD@BA-MIPs still exhibited a significant adsorption capacity (38.78 μmol g−1 at 308 K) for NRG. The regenerated MC-CD@BA-MIPs maintained 92.56% of their initial adsorption capacity through six consecutive cycles. Full article
(This article belongs to the Special Issue Recognition Materials and Separation Applications)
►▼ Show Figures

Figure 1

33 pages, 1525 KB  
Article
Mineral Extraction from Mixed Brine Solutions
by M. A. Salman, M. Ahmed, H. Al-Sairfi and Y. Al-Foudari
Separations 2025, 12(10), 266; https://doi.org/10.3390/separations12100266 - 1 Oct 2025
Viewed by 473
Abstract
Sulfate minerals (SMs), such as BaSO4, SrSO4, and CaSO4, precipitate when incompatible solutions from the oil industry, such as seawater (SW) and high-salinity brine solutions (HSBSs), are mixed during the oil production process. To investigate the potentiality [...] Read more.
Sulfate minerals (SMs), such as BaSO4, SrSO4, and CaSO4, precipitate when incompatible solutions from the oil industry, such as seawater (SW) and high-salinity brine solutions (HSBSs), are mixed during the oil production process. To investigate the potentiality to extract SM by mixing three different brine solutions, such as HSBS-1, -2, and -3, with SW, at different temperatures and pressures, a practical simple model was used to predict the saturation index (SI), the quantity of precipitated minerals (Y), and the induction time (tind) required for precipitation. From the results, it was found that CaSO4 hemihydrate and SrSO4 yield lower amounts of precipitate. BaSO4 precipitation ranges from 20 to 60 mg/L and 1500 mg/L of CaSO4 anhydrous under ambient conditions. These findings suggest that recovering low-solubility minerals is technically feasible and environmentally preferable to direct disposal. Full article
(This article belongs to the Topic Separation Techniques and Circular Economy)
►▼ Show Figures

Figure 1

22 pages, 3564 KB  
Article
Development of a Green Extraction Process from Residues of Assyrtiko Wine Production for Cosmetic Applications
by Styliani Kalafateli, Agni-Areti Freri, Georgios Stavropoulos, Andromachi Tzani and Anastasia Detsi
Separations 2025, 12(10), 265; https://doi.org/10.3390/separations12100265 - 30 Sep 2025
Viewed by 365
Abstract
Vitis vinifera L. cultivar, “Assyrtiko”, is a famous grape variety native to Santorini island. Its wine production residues are rich in bioactive polyphenols, making them valuable for extraction and use in cosmetics. The aim of this work was the development and optimization of [...] Read more.
Vitis vinifera L. cultivar, “Assyrtiko”, is a famous grape variety native to Santorini island. Its wine production residues are rich in bioactive polyphenols, making them valuable for extraction and use in cosmetics. The aim of this work was the development and optimization of an extraction process from “Assyrtiko” Wine Production Residue (AWPR), using a Natural Deep Eutectic Solvent (NaDES) as the extraction medium. Four NaDESs were synthesized and screened for the extraction, and the extracts were evaluated for Total Phenolic Content (TPC) and Total Flavonoid Content (TFC). The NaDES comprising betaine and 1,3-propanediol was chosen for further analysis because of its effectiveness as an extraction solvent. The extraction process was optimized using a Box–Behnken experimental design. The NaDES %w/w content in the NaDES/water system was found to play the most statistically significant role in the quality of the extracts, assessed via TPC and TFC values. The quality of the extract obtained from the optimal conditions was practically stable with respect to TPC and TFC after long storage, suggesting that NaDESs have a potential “protective” effect for the extracted phytochemicals and give energy-efficient character to the process. This extract was also directly incorporated into a moisturizing cosmetic formulation, which remained homogeneous and stable after testing, demonstrating the extract’s potential for cosmetic applications. Full article
(This article belongs to the Special Issue Novel Solvents and Methods for Extraction of Chemicals)
►▼ Show Figures

Figure 1

15 pages, 1303 KB  
Article
Wastewater Sludge Dewatering Enhancement by Flocculant Selection and Electrochemical Pretreatment
by Binbin Yang, Yingxue Sun, Quanze Liu, Xiaobo Wang and Xiaolei Zhang
Separations 2025, 12(10), 264; https://doi.org/10.3390/separations12100264 - 27 Sep 2025
Viewed by 445
Abstract
In wastewater treatment, sludge is generated during both the primary and secondary sedimentation processes. With the growing volume of wastewater, sludge production has increased accordingly. Prior to subsequent treatment or disposal, sludge dewatering is a critical step to reduce volume and improve treatment [...] Read more.
In wastewater treatment, sludge is generated during both the primary and secondary sedimentation processes. With the growing volume of wastewater, sludge production has increased accordingly. Prior to subsequent treatment or disposal, sludge dewatering is a critical step to reduce volume and improve treatment efficiency. The primary challenge lies in the removal of bonded water within the extracellular polymeric substances (EPSs) and the microorganism cells. In this study, electrochemical pretreatment was employed to improve sludge dewatering performance. The optimal electrochemical treatment was achieved at an electrode spacing of 2 cm, a stirring speed of 500 rpm, and an electrolyte (1 M calcium chloride, CaCl2) dosage of 3 mL for 50 min. Subsequently, flocculation was conducted. Compared with the widely used polyacrylamide (PAM), polydimethyldiallylammonium chloride (PDMDAAC) achieved superior dewatering performance with less than half the dosage required. Under the combined treatment, the final moisture content of the sludge cake was reduced to 53.2%. These findings indicate that the combination of Fe/Ti-based electrochemical pretreatment and flocculation process is a promising and efficient strategy for deep sludge dewatering. Full article
(This article belongs to the Topic Advances in Separation Engineering)
►▼ Show Figures

Figure 1

16 pages, 4839 KB  
Article
Bone Density Assessment Through Sodium Poly-Tungstate Gradient Centrifugation: A Preliminary Study on Decades-Old Human Samples
by Barbara Di Stefano, Chiaramaria Stani, Giorgio Marrubini, Barbara Bertoglio, Solange Sorçaburu Ciglieri, Serena Bonin, Carlo Previderè, Giovanni Birarda and Paolo Fattorini
Separations 2025, 12(10), 263; https://doi.org/10.3390/separations12100263 - 27 Sep 2025
Viewed by 441
Abstract
Bone density is considered one of the many factors influencing bone structure and DNA preservation. For this reason, it is of interest in fields such as anthropology, palaeontology, and genetics. This study describes a method for bone density assessment by gradient centrifugation in [...] Read more.
Bone density is considered one of the many factors influencing bone structure and DNA preservation. For this reason, it is of interest in fields such as anthropology, palaeontology, and genetics. This study describes a method for bone density assessment by gradient centrifugation in Sodium Poly-Tungstate (SPT) solutions (from 2.1 to 2.6 g/cm3). Fifty milligrams of bone powder (size range of 20–50 µm) were used, with an average recovery of 89.9 (IC = 3.3% at 95% of probability). In the first phase of the experiment, the protocol was applied to ten femurs: three exhumed from the WWII mass grave of Ossero, three aged (43–50 years old) femurs from a museum collection and four fresh controls. In the subsequent phase, the analysis was extended to three petrous bones, three metacarpals, and three metatarsals exhumed from the WWII mass grave. The SPT density gradient profiles revealed marked differences among the three femur sample sets: more than 80% of the powder from control femurs was recovered in fractions with a density ≤ 2.2 g/cm3, whereas approximately 45% of the femurs from the mass grave showed a density > 2.6 g/cm3. The remaining three aged femurs displayed peculiar density patterns. Among the other bone types, metatarsals showed the lowest density values, followed by petrous bones and metacarpals. To detect degradation signatures, all nineteen bone powders were also analysed by ATR-FTIR. The femurs from the mass grave exhibited spectral features consistent with mineral recrystallisation and degradation of the organic phase, whereas the other three aged femurs showed peculiar spectral profiles; metacarpals, petrous bones and metatarsals showed intermediate spectra. PCA was applied to SPT and ATR-FTIR data, revealing correlations that support the SPT method as a novel tool for bone quality assessment. Although based on a limited sample size, this preliminary work demonstrates that SPT gradient analysis is an effective, low-cost, rapid and reliable method for assessing bone density, with potential applications in different disciplines studying aged bone samples. Lastly, principal component analysis (PCA) revealed a correlation between bone density and the yield of DNA recovered from the ten femoral specimens. Full article
(This article belongs to the Section Bioanalysis/Clinical Analysis)
►▼ Show Figures

Figure 1

15 pages, 3292 KB  
Article
Enhanced Electro-Dewatering of Sludge Through Inorganic Coagulant Pre-Conditioning
by Xiaoyin Yang, Song Huang, Yusong Zhang, Hanjun Wu, Yabin Ma and Bingdi Cao
Separations 2025, 12(10), 262; https://doi.org/10.3390/separations12100262 - 26 Sep 2025
Viewed by 353
Abstract
Sludge electro-dewatering technology is an attractive dewatering technology, but its application is limited by high energy consumption and filter cloth clogging caused by the dissolution of extracellular polymeric substances (EPSs). Thus, the addition of inorganic coagulants is expected to enhance the electro-dewatering efficiency [...] Read more.
Sludge electro-dewatering technology is an attractive dewatering technology, but its application is limited by high energy consumption and filter cloth clogging caused by the dissolution of extracellular polymeric substances (EPSs). Thus, the addition of inorganic coagulants is expected to enhance the electro-dewatering efficiency of waste activated sludge (WAS). In this study, we evaluated the effects of the three typical inorganic coagulants (HPAC, PAC, and FeCl3) on sludge electro-dewatering behavior. The results show that the electro-dewatering rate at the cathode was increased with the raising of the inorganic coagulants dosage, and FeCl3 exhibited the best effect on the improvement of sludge electro-dewatering among the three inorganic coagulants. The zeta potential of the sludge flocs and the electro-osmotic effect were raised with the increasing of the inorganic coagulants dosage. The sludge floc conditioned by FeCl3 is more compact than HPAC and PAC. Moreover, the dissolved EPS content reduced in the sludge electro-dewatering process when inorganic coagulant was added. In comparison to increasing ionic strength, the compression of extracellular polymeric substances (EPSs) plays a more critical role in enhancing the electro-dewatering process of sludge. The addition of inorganic coagulants also reduced the energy consumption during water removal in the electro-dewatering process. Full article
(This article belongs to the Special Issue Advanced Separation Technology for Sludge Wastewater Treatment and Resource Utilization)
►▼ Show Figures

Graphical abstract

14 pages, 1297 KB  
Article
Optimizing Natural Organic Matter Removal from Water by UV/H2O2 Advanced Oxidation Using Central Composite Design
by Hrvoje Juretić, Darko Smoljan, Hrvoje Cajner and Draženka Stipaničev
Separations 2025, 12(10), 261; https://doi.org/10.3390/separations12100261 - 24 Sep 2025
Viewed by 609
Abstract
The inevitable ubiquity of natural organic matter (NOM) in all waters presents a challenge to the proper functioning of water treatment processes. Therefore, minimizing NOM in raw water is crucial to avoid operational issues in subsequent treatment steps. In this experimental study, we [...] Read more.
The inevitable ubiquity of natural organic matter (NOM) in all waters presents a challenge to the proper functioning of water treatment processes. Therefore, minimizing NOM in raw water is crucial to avoid operational issues in subsequent treatment steps. In this experimental study, we aimed to maximize the degradation of NOM using UV/H2O2 advanced oxidation, employing design of experiments (DoE) and response surface methodology (RSM) for process optimization. Experiments were carried out on synthetic water, and the effects of dissolved organic carbon (DOC) content and hydrogen peroxide concentration on DOC removal at neutral pH were examined. NOM isolated from the Suwannee River was used as a representative model. The process was modeled and optimized using Design-Expert 14.0.7.0 software. The highest DOC removal of approximately 34% was observed at a DOC level of ~8 mg L−1 and an H2O2 concentration just below 250 mg L−1. Degradation products were analyzed by ultra-high-performance liquid chromatography coupled with hybrid quadrupole time-of-flight mass spectrometry, revealing sixteen compounds, mostly long-chain saturated fatty acids. Finally, the energy efficiency of the experimental setup was assessed and discussed. Full article
(This article belongs to the Special Issue Eco-Friendly Innovations for Water Purification: Advanced Oxidation and Sustainable Cleanup Solutions)
►▼ Show Figures

Figure 1

14 pages, 4132 KB  
Article
Pore-Engineered Magnetic Biochar: Optimizing Pyrolysis and Fe3O4 Loading for Targeted Chlorinated Aliphatic Hydrocarbon (CAH) Adsorption
by Fengyuan Zhang, Zixuan Li, Xiaohan Dou, Zhengwei Liu, Yan Xie, Jingru Liu and Shucai Zhang
Separations 2025, 12(10), 260; https://doi.org/10.3390/separations12100260 - 24 Sep 2025
Viewed by 619
Abstract
Chlorinated aliphatic hydrocarbons (CAHs) are some of the most widely distributed organic pollutants in underground environments and have high biological toxicity. This research aims to prepare an effective adsorbent comprising biochar and magnetite (MBC) to remove CAH pollution from soil. Optimization of the [...] Read more.
Chlorinated aliphatic hydrocarbons (CAHs) are some of the most widely distributed organic pollutants in underground environments and have high biological toxicity. This research aims to prepare an effective adsorbent comprising biochar and magnetite (MBC) to remove CAH pollution from soil. Optimization of the preparation and adsorption performance of MBC was investigated. The results of the adsorption experiment, combined with scanning electron microscopy (SEM) observations, show that the best raw material and pyrolysis temperature were coconut shell and 500 °C respectively. The Fourier transform infrared (FTIR) and X-ray diffraction (XRD) pattern characterizations, as well as the adsorption results, demonstrated the successful synthesis and enhancement effect of MBC for CAHs. The adsorption of CAHs on Fe3O4-loaded biochar was improved by 34.40–222.25% during pyrolysis at 500–900 °C. Additionally, MBC with a 10% Fe3O4 content had the best effect on three types of CAHs at low concentrations. A comparative pore analysis of MBC with different doses of Fe3O4 was carried out to reveal the relationship between the pore characteristics and adsorption properties. Furthermore, competitive adsorption experiments demonstrated that 4 wt% MBC addition significantly reduced the soil-bound TCE by 48.6%. Overall, these results indicated that MBC was an effective adsorbent for CAH removal from the polluted underground environment. Full article
(This article belongs to the Special Issue Removal of Environmental Pollutants and Bioremediation Strategies)
►▼ Show Figures

Figure 1

14 pages, 1653 KB  
Article
Efficient Adsorptive Removal of Phosphonate Antiscalant HEDP by Mg-Al LDH
by Changjin Guo, Lejiaqi Zhang, Qi Zhang, Congcong Ni, Ning Deng and Xin Huang
Separations 2025, 12(10), 259; https://doi.org/10.3390/separations12100259 - 24 Sep 2025
Cited by 2 | Viewed by 545
Abstract
Phosphonate-based antiscalants such as 1-hydroxyethane-1,1-diphosphonic acid (HEDP) are extensively employed in industrial water treatment but pose significant environmental challenges due to their persistence and phosphorus content. In this study, Mg-Al layered double hydroxide (Mg-Al LDH) was synthesized and evaluated for its capacity to [...] Read more.
Phosphonate-based antiscalants such as 1-hydroxyethane-1,1-diphosphonic acid (HEDP) are extensively employed in industrial water treatment but pose significant environmental challenges due to their persistence and phosphorus content. In this study, Mg-Al layered double hydroxide (Mg-Al LDH) was synthesized and evaluated for its capacity to adsorb and remove HEDP. Mg-Al LDH showed a pronounced adsorption affinity and an exceptionally high capacity of 276.0 mg g−1 at pH 7.0. The adsorption process was remarkably fast, attaining 97% of equilibrium uptake within 45 min at 298 K. The adsorption data fit well to the Elovich kinetic model and the Langmuir isotherm, indicating that the adsorption process is dominated by chemisorption. Thermodynamic analysis further confirmed its spontaneous nature. Additionally, Mg-Al LDH demonstrated strong tolerance to environmental fluctuations. Characterization techniques, including XRD, FTIR, and zeta potential measurements, confirmed that HEDP adsorption onto Mg-Al LDH primarily occurs via surface complexation with metal sites and electrostatic attraction. These findings demonstrate that Mg-Al LDH is a highly effective adsorbent for removing persistent phosphonate pollutants from wastewater streams. Full article
►▼ Show Figures

Figure 1

15 pages, 2291 KB  
Article
Eco-Friendly Dye Removal: Black Cumin Seed Press Cake for Toluidine Blue Adsorption
by Galia Gentscheva, Paunka Vassileva, Christina Tzvetkova, Aleksandar Pashev, Ina Yotkovska, Metodi Mladenov and Tsvetan Vassilev
Separations 2025, 12(10), 258; https://doi.org/10.3390/separations12100258 - 23 Sep 2025
Viewed by 432
Abstract
This research investigates the potential of Seed Press Cake of Nigella sativa (SPCN) as a low-cost, eco-friendly biosorbent for the removal of the cationic dye Toluidine Blue (TB) from aqueous solutions. The physicochemical properties of the material were characterized using Fourier-transform infrared (FTIR) [...] Read more.
This research investigates the potential of Seed Press Cake of Nigella sativa (SPCN) as a low-cost, eco-friendly biosorbent for the removal of the cationic dye Toluidine Blue (TB) from aqueous solutions. The physicochemical properties of the material were characterized using Fourier-transform infrared (FTIR) spectroscopy, nitrogen adsorption–desorption isotherms, and scanning electron microscopy (SEM). Adsorption performance was evaluated under varying conditions, with the process best described by the pseudo-second-order kinetic model and the Langmuir isotherm, indicating monolayer adsorption. The maximum adsorption capacity was determined to be 305 mg·g−1 at 20 °C. Thermodynamic analysis revealed that the adsorption is spontaneous, exothermic, and entropy-driven. FTIR analysis indicated that TB interacts with SPCN primarily via physical interactions, including electrostatic attraction, van der Waals forces, and hydrogen bonding, without strong chemical bonding. These findings demonstrate the high potential of black cumin seed waste as a sustainable and efficient biosorbent for dye removal in wastewater treatment. Full article
(This article belongs to the Special Issue Applications of Adsorbent Materials in Water and Wastewater Treatment)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-31
Previous Issue
Next Issue
Back to TopTop