Journal Description
Separations
Separations
- formerly Chromatography - is an international, peer-reviewed, open access journal on separation and purification science and technology in all areas of chemical, biological, physical science, and separation performance published monthly online by MDPI. The Central European Group of Separation Sciences (CEGSS) is affiliated with Separations and their members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 13.6 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journal: Purification.
Impact Factor:
2.6 (2022);
5-Year Impact Factor:
2.7 (2022)
Latest Articles
Pomegranate Juice Clarification Using Ultrafiltration: Influence of the Type of Variety and Degree of Ripeness
Separations 2024, 11(5), 134; https://doi.org/10.3390/separations11050134 - 26 Apr 2024
Abstract
Fruit consumption guarantees the supply of most of the necessary nutrients for a complete and balanced diet, as it is a relevant source of vitamins, minerals, and antioxidants. In particular, pomegranate has very interesting medicinal properties, such as an anti-inflammatory effect and the
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Fruit consumption guarantees the supply of most of the necessary nutrients for a complete and balanced diet, as it is a relevant source of vitamins, minerals, and antioxidants. In particular, pomegranate has very interesting medicinal properties, such as an anti-inflammatory effect and the protection of the cardiovascular system, among others. During pomegranate juice production, it appears cloudy and must be clarified to remove suspended solids such as colloids and high-molecular weight tannins. The membrane clarification process is a cost-effective alternative to the conventional methods, resulting in a high-quality product. In this work, the clarification of pomegranate juice using the Triple System Model F1 membrane module was carried out for the Mollar and Wonderful varieties with early and late maturity. Three ultrafiltration membranes with different molecular weight cut-off and different chemical compositions were used. The rejection coefficient and permeate flux (which represent the selectivity of the membranes and the process efficiency, respectively) were measured. GR-40PP showed the best results in terms of membrane selectivity and process efficiency, achieving adequate physicochemical juice parameters. Regarding the comparison of the maturity degree, in general terms, the Mollar variety showed better results. Ripe pomegranates showed greater selectivity, while the process efficiency was higher for the early samples.
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(This article belongs to the Section Analysis of Natural Products and Pharmaceuticals)
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Phthalates: The Main Issue in Quality Control in the Beverage Industry
by
Alessia Iannone, Cristina Di Fiore, Fabiana Carriera, Pasquale Avino and Virgilio Stillittano
Separations 2024, 11(5), 133; https://doi.org/10.3390/separations11050133 - 26 Apr 2024
Abstract
Phthalate esters (PAEs) are a group of chemicals used to improve the flexibility and durability of plastics. The chemical properties and the resistance to high temperatures promote their degradation and release into the environment. Food and beverages can be contaminated by PAEs through
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Phthalate esters (PAEs) are a group of chemicals used to improve the flexibility and durability of plastics. The chemical properties and the resistance to high temperatures promote their degradation and release into the environment. Food and beverages can be contaminated by PAEs through the migration from packaging material because they are not covalently bound to plastic and also via different kinds of environmental sources or during processing. For instance, alcoholic drinks in plastic containers are a particular risk, since the ethanol contained provides a good solubility for PAEs. According to its role as an endocrine disruptor compound and its adverse effects on the liver, kidney, and reproductive and respiratory systems, the International Agency on Research Cancer (IARC) classified di-(2-ethylhexyl) phthalate (DEHP) as a possible human carcinogen. For this reason, to control human exposure to PAEs, many countries prohibited their use in food as non-food substances. For example, in Europe, the Commission Regulation (EU) 2018/2005 restricts the use of DEHP, dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), and diisobutyl phthalate (DiBP) to a concentration equal to or below 0.1 by weight in plasticizers in articles used by consumers or in indoor areas. There are reports from the US Food and Drug Administration (FDA) that some beverages (and food as well), particularly fruit juices, contain high levels of phthalates. In some cases, the deliberate adulteration of soft drinks with phthalate esters has been reported. This paper would like to show the difficulties of performing PAE analysis in beverage matrices, in particular alcoholic beverages, as well as the main solutions provided for quality control in the industrial branches.
Full article
(This article belongs to the Section Analysis of Food and Beverages)
Open AccessArticle
Metabolite Profiling and Molecular Network Shows Kinkeloids as Promoting of Collagen Synthesis from Combretum micranthum
by
Souhila Messaili, Doha Haggouch, Mikaela Bignard, Pierre-Eric Campos, Emilie Destandau and Eldra Delannay
Separations 2024, 11(5), 132; https://doi.org/10.3390/separations11050132 - 26 Apr 2024
Abstract
Combretum micranthum, a plant native to Africa, has a well-documented traditional use in the treatment of various ailments such as fever, diabetes, and malaria. Its pharmaceutical benefits include nephroprotective, anti-inflammatory, antioxidant, and antimicrobial properties, which were proven. In addition, its potential for
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Combretum micranthum, a plant native to Africa, has a well-documented traditional use in the treatment of various ailments such as fever, diabetes, and malaria. Its pharmaceutical benefits include nephroprotective, anti-inflammatory, antioxidant, and antimicrobial properties, which were proven. In addition, its potential for cosmetic applications is being explored due to its depigmenting, anti-inflammatory, and UV-damage-repairing properties. This article investigates the molecular composition and new cosmetically relevant biological activity of C. micranthum and enriched fractions to begin the establishment of the structure–activity relationship. Firstly, an extract of C. micranthum was prepared and selected for its overall biological response and then fractionated to obtain simplified molecular fractions. One fraction was particularly enriched in kinkeloids, a specific family of compounds to this species. All the fractions and the crude extract were then tested on biological targets to evaluate and compare their cosmetic activities. Molecular networks were constructed from the UHPLC-MS/HRMS data to better characterize the extract and fractions and to highlight structure–activity relationships. This study highlights the metabolic profiling of a butylene glycol extract of C. micranthum, showing its main chemical families and revealing that the kinkeloids, identified by HRMS and NMR, promote an increase in collagen I synthesis, an interesting cosmetic activity neither previously described for these compounds and neither for C. micranthum extract.
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(This article belongs to the Special Issue Bioactive Compounds from Natural Sources: Extraction, Characterization, Evaluation and Application)
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Open AccessArticle
Comparative Kinetic Analysis of Triclosan Degradation under UV-C and Simulated Solar Irradiation
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Lázaro Adrián González-Fernández, Myriam Chems, Nahum Andrés Medellín-Castillo, Ventura Castillo-Ramos, Manuel Sánchez-Polo, Javier E. Vilasó-Cadre and Raúl Ocampo-Pérez
Separations 2024, 11(5), 131; https://doi.org/10.3390/separations11050131 - 25 Apr 2024
Abstract
This research delves deeply into the intricate degradation kinetics of triclosan, employing two distinct methodologies: UV and simulated solar irradiation. Through a comprehensive comparative analysis, the study endeavors to elucidate the efficacy of these techniques, aiming to shed light on their respective methodological
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This research delves deeply into the intricate degradation kinetics of triclosan, employing two distinct methodologies: UV and simulated solar irradiation. Through a comprehensive comparative analysis, the study endeavors to elucidate the efficacy of these techniques, aiming to shed light on their respective methodological strengths and limitations. The study compares the efficacy of UV and simulated solar irradiation techniques for triclosan degradation, revealing that both methods exhibit effectiveness in degrading triclosan, with variations observed in degradation rates and byproduct formation. Through a detailed examination of the kinetics of triclosan degradation, the study reveals the intricate pathways and mechanisms involved in the photodegradation process. Results highlight the influence of irradiance levels and residence times on degradation efficiency. The research identifies optimal conditions for triclosan degradation, emphasizing the importance of residence time and irradiance levels. Results show that a residence time of 4 h and an irradiance level of 450 W m−2 maximize degradation efficiency. Analysis of degradation byproducts provides insights into the transformation pathways of triclosan under UV and simulated solar irradiation, indicating the formation of 2,4-dichlorophenol, quinone, and hydroquinone as primary byproducts.
Full article
(This article belongs to the Special Issue Application of Biosorbents in Environmental Purification)
Open AccessReview
Application of Magnetic Separation Technology in Resource Utilization and Environmental Treatment
by
Jiangang Ku, Kunpeng Wang, Qian Wang and Zhongyun Lei
Separations 2024, 11(5), 130; https://doi.org/10.3390/separations11050130 - 24 Apr 2024
Abstract
Magnetic separation technology is a physical separation method that uses the differences in magnetism between matter to separate them from each other by different motion behaviors in a non-uniform magnetic field. It is highly efficient, green, and environmentally friendly, with little change in
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Magnetic separation technology is a physical separation method that uses the differences in magnetism between matter to separate them from each other by different motion behaviors in a non-uniform magnetic field. It is highly efficient, green, and environmentally friendly, with little change in the physical and chemical properties of raw materials. Magnetic separation technology is commonly used in the field of mineral processing engineering for magnetite, hematite, titanite, and other magnetic ferrous metal oxide minerals. This paper summarizes the application of magnetic separation technology for resource utilization and environmental treatment in different fields, such as non-metal decomposition, valuable metal recovery, use of magnetic carrier chemical separation, biomedical targeted magnetic separation, and use of magnetic species separation in water and wastewater treatment. We seek to review the application and potential of magnetic separation technology in various fields, emphasize their key role, and explore possible directions for their future development.
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(This article belongs to the Special Issue Application of Magnetic Separation Technology in Green Production)
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Open AccessArticle
The Removal of As(III) Using a Natural Laterite Fixed-Bed Column Intercalated with Activated Carbon: Solving the Clogging Problem to Achieve Better Performance
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Régie Dimanche Ouedraogo, Corneille Bakouan, Abdoul Karim Sakira, Brahima Sorgho, Boubié Guel, Touridomon Issa Somé, Anne-Lise Hantson, Eric Ziemons, Dominique Mertens, Philippe Hubert and Jean-Michel Kauffmann
Separations 2024, 11(4), 129; https://doi.org/10.3390/separations11040129 - 22 Apr 2024
Abstract
Natural laterite fixed-bed columns intercalated with two types of layers (inert materials, such as fine sand and gravel, and adsorbent materials, such as activated carbon prepared from Balanites aegyptiaca (BA-AC)) were used for As(III) removal from an aqueous solution. Investigations were carried out
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Natural laterite fixed-bed columns intercalated with two types of layers (inert materials, such as fine sand and gravel, and adsorbent materials, such as activated carbon prepared from Balanites aegyptiaca (BA-AC)) were used for As(III) removal from an aqueous solution. Investigations were carried out to solve the problem of column clogging, which appears during the percolation of water through a natural laterite fixed-bed column. Experimental tests were conducted to evaluate the hydraulic conductivities of several fixed-bed column configurations and the effects of various parameters, such as the grain size, bed height, and initial As(III) concentration. The permeability data show that, among the different types of fixed-bed columns investigated, the one filled with repeating layers of laterite and activated carbon is more suitable for As(III) adsorption, in terms of performance and cost, than the others (i.e., non-intercalated laterite; non-intercalated activated carbon, repeating layers of laterite and fine sand; and repeating layers of laterite and gravel). A study was carried out to determine the most efficient column using breakthrough curves. The breakthrough increased from 15 to 85 h with an increase in the bed height from 20 to 40 cm and decreased from 247 to 32 h with an increase in the initial As(III) concentration from 0.5 to 2 mg/L. The Bohart–Adams model results show that increasing the bed height induced a decrease in the kAB and N0 values. The critical bed depths determined using the bed depth service time (BDST) model for As(III) removal were 15.23 and 7.98 cm for 1 and 20% breakthroughs, respectively. The results show that the new low-cost adsorptive porous system based on laterite layers with alternating BA-AC layers can be used for the treatment of arsenic-contaminated water.
Full article
(This article belongs to the Special Issue Development and Applications of Porous Materials in Adsorptions)
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Open AccessReview
Bioactives in Cocoa: Novel Findings, Health Benefits, and Extraction Techniques
by
Kristina Tušek, Davor Valinger, Tamara Jurina, Tea Sokač Cvetnić, Jasenka Gajdoš Kljusurić and Maja Benković
Separations 2024, 11(4), 128; https://doi.org/10.3390/separations11040128 - 19 Apr 2024
Abstract
Theobroma cacao L. seeds, commonly known as cocoa beans, are the foundation for cocoa and chocolate production. Following harvest, these beans undergo a multi-step processing chain including fermentation, drying, roasting, and grinding. This process yields cocoa solids, cocoa butter, and cocoa powder—all fundamental
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Theobroma cacao L. seeds, commonly known as cocoa beans, are the foundation for cocoa and chocolate production. Following harvest, these beans undergo a multi-step processing chain including fermentation, drying, roasting, and grinding. This process yields cocoa solids, cocoa butter, and cocoa powder—all fundamental ingredients in the food and beverage industry. Beyond its sensory appeal (flavor, aroma, and texture), cocoa has garnered significant interest for its potential health benefits attributed to a rich profile of bioactive compounds. Cocoa is a well-documented source of polyphenolics, specifically flavanols, alongside methylxanthines, phytosterols, and dietary fibers. These constituents have been associated with a diverse range of bioactivities, including antioxidant, anti-carcinogenic, anti-diabetic, anti-inflammatory, anti-obesity, and anti-allergenic properties, potentially contributing to overall health maintenance. Efficient extraction techniques are crucial for maximizing the recovery of these valuable bioactive components from cocoa plant material. Modern methods are continuously being explored to optimize this process. This review focuses on the established health benefits associated with the bioactive compounds present in cocoa. Additionally, it will explore and discuss contemporary approaches for the extraction of these bioactive compounds from this plant source.
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(This article belongs to the Special Issue Research Progress for Isolation of Plant Active Compounds)
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Cymbopogon citratus Water Extract and Methyl Jasmonate Improve Polyunsaturated Fatty Acid Metabolism in Taiwanofungus camphoratus Mycelia
by
Yeyan Wen, Zixuan Lin, Dongmei Lin, Biaosheng Lin, Gexin Chen, Zhanxi Lin and Jing Li
Separations 2024, 11(4), 127; https://doi.org/10.3390/separations11040127 - 19 Apr 2024
Abstract
A rare medicinal fungus called Taiwanofungus camphoratus gives people resistance to illness. In order to effectively obtain high−quality T. camphoratus mycelia, we added Cymbopogon citratus (lemongrass) water extract (LWE), which was prepared using hot water and dry lemongrass leaves and methyl jasmonate (MJ)
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A rare medicinal fungus called Taiwanofungus camphoratus gives people resistance to illness. In order to effectively obtain high−quality T. camphoratus mycelia, we added Cymbopogon citratus (lemongrass) water extract (LWE), which was prepared using hot water and dry lemongrass leaves and methyl jasmonate (MJ) as an additive, in order to cultivate T. camphoratus mycelia. The components of LWE were identified by gas chromatography–mass spectrometry as glucose (61.66%) and galactose (17.10%). Compare to the basal medium, 0.5–2.5 g·L−1 LWE and 5–25 μmol·L−1 MJ can enhance the proliferation of mycelia and the metabolism of polyunsaturated fatty acids (PUFAs). Among them, the T. camphoratus mycelia growth rate increased to 1.292 ± 0.01 cm·d−1 and 1.285 ± 0.05 cm·d−1, improving by 2.5 g·L−1 LWE and 25 μmol·L−1 MJ, respectively. PUFAs are mainly composed of linoleic acid (LA) and oleic acid (OA). The contents of LA and OA were 0.28 ± 0.02 mg·g−1 and 0.23 ± 0.05 mg·g−1 after MJ treatment, while the contents of LA and OA were 0.08 ± 0.03 mg·g−1 and 0.05 ± 0.05 mg·g−1 after LWE treatment. Transcriptome analyses revealed that 367 and 232 genes within MJ and LWE treatment were significantly different from the basal medium. Out of 13 unigenes, FAD2−2, SCD, and FAD2−1 had the highest expression levels according to the quantitative RT−PCR result. The bioinformatics analysis showed that three genes are closely related to the M8 chromosome of T. camphoratus, and they are hydrophobic transmembrane proteins. The identification and investigation of fatty acid genes in T. camphoratus mycelia will be improved by our findings.
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(This article belongs to the Special Issue Research Progress for Isolation of Plant Active Compounds)
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Laser Manufacturing of Superwetting Oil–Water Separation Materials: A Review
by
Wei Xiong, Linfeng Zhu, Ruisong Jiang and Chaolang Chen
Separations 2024, 11(4), 126; https://doi.org/10.3390/separations11040126 - 19 Apr 2024
Abstract
The frequent occurrence of oil spills and the massive discharge of oily wastewater pose a significant threat to sustainable and healthy human development. Therefore, it is of importance to effectively separate oil–water mixtures. Inspired by nature, many superwetting surfaces/materials for oil–water separation have
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The frequent occurrence of oil spills and the massive discharge of oily wastewater pose a significant threat to sustainable and healthy human development. Therefore, it is of importance to effectively separate oil–water mixtures. Inspired by nature, many superwetting surfaces/materials for oil–water separation have been developed in recent years. However, these surfaces/materials are subject to certain limitations and are unable to fully meet practical needs. With the advancement of laser technology, a novel solution has been provided for fabricating superwetting oil–water separation materials. Based on the design theory and separation mechanism, this paper summarizes the research progress of the laser-fabricated superwetting surfaces/materials for oil–water separation in recent years. First, the basic wetting theory, design strategy, and oil–water separation mechanism of the laser-fabricated materials are introduced in detail. Subsequently, the laser-fabricated oil–water separation materials, including superoleophilic/superhydrophobic materials, superhydrophilic/superoleophobic materials, and materials with reversible or superamphiphilic wettability, are systematically summarized and analyzed. Finally, the challenges and future research directions of laser-fabricated superwetting oil–water separation materials are discussed.
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(This article belongs to the Special Issue Advanced Oil–Water Separation Technology)
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Adsorption of Fluoride from Water Using Aluminum-Coated Silica Adsorbents: Comparison of Silica Sand and Microcrystalline Silica
by
Kiana Modaresahmadi, Amid P. Khodadoust and James Wescott
Separations 2024, 11(4), 125; https://doi.org/10.3390/separations11040125 - 19 Apr 2024
Abstract
Two aluminum-coated silica adsorbents were evaluated using silica sand and microcrystalline silica as aluminum-oxide-based adsorbents with different crystalline silica base materials. The aluminum coating contained mainly amorphous aluminum oxides for both aluminum-coated silica adsorbents. The adsorption of fluoride onto both adsorbents was favorable
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Two aluminum-coated silica adsorbents were evaluated using silica sand and microcrystalline silica as aluminum-oxide-based adsorbents with different crystalline silica base materials. The aluminum coating contained mainly amorphous aluminum oxides for both aluminum-coated silica adsorbents. The adsorption of fluoride onto both adsorbents was favorable according to the Langmuir and Freundlich adsorption equations, while the physical adsorption of fluoride occurred for both adsorbents according to the Dubinin–Raduskevish (D-R) equation. The adsorption of fluoride was stronger for aluminum-coated silica sand based on adsorption parameters from the Langmuir, Freundlich, and D-R adsorption equations, with the stronger binding of fluoride likely due to the observed greater specific adsorption. The adsorption capacity determined using the Langmuir equation was about 7 times greater for aluminum-coated microcrystalline silica primarily due to the 1.22-orders-of-magnitude-larger surface area of aluminum-coated microcrystalline silica, whereas the surface-normalized adsorption capacity was 2.4 times greater for aluminum-coated silica sand, possibly due to more aluminum being present on the surface of silica sand. Fluoride adsorption occurred over a broad pH range from 3 to 10 for both adsorbents, with nearly the same pHPZC of 9.6, while aluminum-coated microcrystalline silica displayed a higher selectivity for fluoride adsorption from different natural water sources.
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(This article belongs to the Section Materials in Separation Science)
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Open AccessCommunication
Experimental Study on the Separation of Lithium and Imidazolium Ions Using a Cation Exchange Membrane
by
Jingyi Xue, Xiang Meng, Runci Wang, Zhongwei Yuan and Weifang Zheng
Separations 2024, 11(4), 123; https://doi.org/10.3390/separations11040123 - 19 Apr 2024
Abstract
The separation of Li+ and [Bmim]+(1-Butyl-3-methylimidazolium) using a cation exchange membrane in an electric field is studied in this work. The effects of the type of cation exchange membrane, current density, total cation concentration, temperature, and anion types on the
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The separation of Li+ and [Bmim]+(1-Butyl-3-methylimidazolium) using a cation exchange membrane in an electric field is studied in this work. The effects of the type of cation exchange membrane, current density, total cation concentration, temperature, and anion types on the separation efficiency are investigated. The results indicate that it is feasible to achieve the efficient separation of Li+ and [Bmim]+ using the selectivity of cation exchange membranes under an electric field. The CIMS membrane (a type of cation exchange membrane produced by ASTOM Corporation) shows obvious selectivity of Li+ from [Bmim]+. When the current density is 5 mA/cm2 and the feed concentrations of Li+ and [Bmim]+ are 0.3 mol/L and 0.2 mol/L, respectively, the selective transport coefficient of CIMS can reach 5.9 in the first 120 min of the process. The separation efficiency can be effectively improved by reducing the current density and increasing the total cation concentration. Decreasing the feed temperature can slightly improve the separation efficiency. Changing the type of anion in the feed from chloride to acetate has no detectable effect on the separation.
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(This article belongs to the Topic Membrane Separation Technology Research)
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Open AccessArticle
Extraction of Copper from Copper Concentrate by Indigenous Association of Iron-Oxidizing Bacteria
by
Arevik Vardanyan, Ruiyong Zhang, Anna Khachatryan, Zaruhi Melkonyan, Arshavir Hovhannisyan, Sabine Willscher, Andreas Kamradt, Manuel Jost, Yimeng Zhang, Can Wang and Narine Vardanyan
Separations 2024, 11(4), 124; https://doi.org/10.3390/separations11040124 - 18 Apr 2024
Abstract
Bioleaching of Cu from the copper concentrate of Armanis gold-bearing polymetallic ore (Armenia) was investigated. The main objective was revealing high active bacteria and their association, as well as optimizing the bioleaching process with their application to ensure the most efficient recovery of
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Bioleaching of Cu from the copper concentrate of Armanis gold-bearing polymetallic ore (Armenia) was investigated. The main objective was revealing high active bacteria and their association, as well as optimizing the bioleaching process with their application to ensure the most efficient recovery of copper from the tested concentrate. To obtain optimal bacterial associations, bottom-up and top-down approaches were used. Bioleaching of copper concentrate was carried out using pure cultures of iron- and sulfur-oxidizing bacteria and their mixed culture, as well as indigenous bacterial consortium. Comparative studies of copper bioleaching by mixed cultures of Acidithiobacillus caldus, Leptospirillum ferriphilum CC, Sulfobacillus thermosulfidooxidans 6, and indigenous consortium Arm of iron-oxidizing bacteria were performed. At the beginning of bioleaching, the amounts of extracted copper by mixed culture and Arm consortium were equal; afterward, between 20–27 days, the Arm indigenous consortium showed significantly higher activity in terms of copper extraction. In parallel, mineralogical and liberation analyses of feed material and bioleaching residues were performed.
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(This article belongs to the Section Purification Technology)
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Open AccessReview
The Removal of Per- and Poly-Fluoroalkyl Substances from Water: A Review on Destructive and Non-Destructive Methods
by
Natalia Malouchi, Stella Chatzimichailidou, Athanasia K. Tolkou, George Z. Kyzas, Loris Calgaro, Antonio Marcomini and Ioannis A. Katsoyiannis
Separations 2024, 11(4), 122; https://doi.org/10.3390/separations11040122 - 18 Apr 2024
Abstract
PFAS, or per- and poly-fluoroalkyl substances, are a broad group of man-made organic compounds that are very persistent, mobile, and tend to bioaccumulate. Their removal from different environmental media is becoming increasingly important because they are associated with a multitude of (eco)toxicological effects
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PFAS, or per- and poly-fluoroalkyl substances, are a broad group of man-made organic compounds that are very persistent, mobile, and tend to bioaccumulate. Their removal from different environmental media is becoming increasingly important because they are associated with a multitude of (eco)toxicological effects on both humans and the environment. PFAS are detected in wastewater, groundwater, drinking water, and surface water, with the subcategories of PFOS and PFOA being the most detected. These organic compounds are divided into polymeric and non-polymeric groups. Non-polymeric PFAS are of great research interest due to their frequent detection in the environment. Numerous methods have been applied for the removal of PFAS and are divided into destructive and non-destructive (separation) techniques. Given the strength of the C–F bond, the destruction of PFAS is challenging, while for most of the separation techniques, the management of isolated PFAS requires further consideration. Most of the techniques have been applied to small-scale applications and show some limitations for larger applications, even though they are promising. Adsorption is an environmentally sustainable, economical, and high-performance technique that is applied to remove several classes of emerging pollutants from water. In this review, the use of various types of adsorbents for PFAS removal from water is reported, as well as the expected adsorption mechanisms. There are several technologies being considered and developed to manage PFAS; however, they are still in the experimental stage, with each showing its appeal for potential larger applications.
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(This article belongs to the Special Issue Removal of Metals or Other Toxic Substances from Wastewaters by Natural Sorbents)
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Open AccessArticle
The Molecular Identification and Comprehensive Analysis of Klebsiella pneumoniae Isolated from Industrial Wastewater
by
Kai Yan, Changfu Li, Weiyu Wang, Juan Guo and Haifeng Wang
Separations 2024, 11(4), 121; https://doi.org/10.3390/separations11040121 - 17 Apr 2024
Abstract
Industrial wastewater typically contains many organic and inorganic pollutants and is also contaminated by various microorganisms. Microbial species in industrial wastewater have not been extensively investigated. In this experiment, a Klebsiella pneumoniae strain was isolated for the first time from industrial wastewater containing
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Industrial wastewater typically contains many organic and inorganic pollutants and is also contaminated by various microorganisms. Microbial species in industrial wastewater have not been extensively investigated. In this experiment, a Klebsiella pneumoniae strain was isolated for the first time from industrial wastewater containing a high concentration of sulfate and phosphate. Mass spectrometry, genetic analysis, and biochemical identification were conducted to understand the genetic and biochemical characteristics of this Klebsiella pneumoniae strain recovered from industrial wastewater. Growth experiments revealed that it exhibited an excellent growth rate in nutrient broth. Further analyses showed that the strain was sensitive to most antibiotics but resistant to chloramphenicol and nitrofurantoin. It also exhibited significant resistance to piperacillin/tazobactam and cefotaxime/clavulanic acid. Resistance gene experiments indicated the presence of gyrA, OqxB, and ParC genes associated with antibiotic resistance in the isolated Klebsiella pneumoniae strain. Proteomics uncovered the following three proteins related to drug resistance: the multi-drug resistant outer membrane protein MdtQ, the multi-drug resistant secretion protein, and the modulator of drug activity B, which are coexistent in Klebsiella pneumoniae. Proteomics and bioinformatics analyses further analyzed the protein composition and functional enrichment of Klebsiella pneumoniae. The isolation of Klebsiella pneumoniae from a high concentration in sulfate and phosphate industrial wastewater provides a new direction for further research on the characteristics and drug resistance traits of industrial wastewater microorganisms and the potential risks they may pose when released into the environment.
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(This article belongs to the Topic Sustainable Technologies for Water Purification)
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Enhancing Recovery of Ultra-Fine Magnetite from Low-Iron-Grade Cyanidation Tailings by Optimizing Flow Field Parameters of Low-Intensity Magnetic Separation (LIMS)
by
Yingjie Chen, Yaxiong Jiang, Yongjun Xian and Luzheng Chen
Separations 2024, 11(4), 120; https://doi.org/10.3390/separations11040120 - 16 Apr 2024
Abstract
The characteristics of iron minerals in cyanidation tailings with a low iron grade were determined via chemical composition analysis, iron phase analysis, and mineral liberation analysis (MLA). The results showed that the cyanidation tailings contained 15.68% iron, mainly occurring in the form of
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The characteristics of iron minerals in cyanidation tailings with a low iron grade were determined via chemical composition analysis, iron phase analysis, and mineral liberation analysis (MLA). The results showed that the cyanidation tailings contained 15.68% iron, mainly occurring in the form of magnetite (19.66%) and limonite (79.91%), in which 16.52% magnetite and 65.90% limonite particles were fully liberated. Most ultra-fine magnetite grains were adjacent and wrapped with limonite to form complex intergrowths, which resulted in low-efficiency magnetite recovery in low-intensity magnetic separation (LIMS) and adversely affected the downstream high-gradient magnetic separation (HGMS) process. Thus, in this work, the optimization of the flow field was proposed to enhance the separation of ultra-fine magnetite from the cyanidation tailings using pilot-scale LIMS separation, and the controllable parameters (including feed flow, separation gap, drum rotating speed, and solid weight) affecting ultra-fine magnetite capture were investigated. Under optimized conditions, a high-grade magnetite concentrate assaying 63.31% Fe with 86.46% magnetite recovery was produced, which, respectively, increased by 0.76% and 15.22%, compared with those obtained from industrial production. In addition, from the flow dynamics simulation, it was found that the magnetite particles in the −6 µm ultra-fine fraction were lost much more easily than those of coarser fractions due to the relatively enhanced hydrodynamic drag force acting on the particles compared with the magnetic force. However, this loss would be effectively reduced with the regulation and control of the flow field. The iron recoveries in the −16~+6 µm and −6 µm fractions of magnetite concentrate increased by 3.66% and 4.42%, respectively, under optimized hydrodynamic conditions. This research outcome provides a valuable reference for the economic and effective utilization of iron resources from such solid wastes.
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(This article belongs to the Special Issue Application of Magnetic Separation Technology in Green Production)
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Combination of Natural Deep Eutectic Solvents and Nano-Liquid Chromatography towards White Analytical Chemistry: A Practical Application
by
Álvaro Santana-Mayor, Giovanni D’Orazio, Salvatore Fanali, Miguel Ángel Rodríguez-Delgado and Bárbara Socas-Rodríguez
Separations 2024, 11(4), 119; https://doi.org/10.3390/separations11040119 - 16 Apr 2024
Abstract
In this work, a green and practical analytical method based on natural deep eutectic solvents (NADES) as extraction agents and nano-liquid chromatography as a separation technique was developed. To demonstrate the applicability of the methodology, alkylphenols and bisphenol A were evaluated as model
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In this work, a green and practical analytical method based on natural deep eutectic solvents (NADES) as extraction agents and nano-liquid chromatography as a separation technique was developed. To demonstrate the applicability of the methodology, alkylphenols and bisphenol A were evaluated as model compounds in olive and sunflower oils as model fatty samples by liquid–liquid microextraction. With this aim, several NADES based on mixtures of choline chloride with glycerol, lactic, ascorbic, and citric acids or glycerol with amino acids were evaluated as potential extraction solvents. In addition, to select the most suitable stationary phase for the separation of this group of contaminants, some stationary phases were tested, including Pinnacle II phenyl, Cogent Bidentate C18™, and XBridge® C18. The last one provided the best performance with an analysis time of 11 min. To solve the problem of the compatibility of hydrophilic NADES with chromatographic systems without harming the solubility of analytes, different aqueous organic mixtures were tested. Methanol/water mixtures were the most suitable as an injection solvent. Finally, following the White Analytical Chemistry principles, different tools were used to evaluate the greenness, the practicality, and applicability of the method based on the Analytical Eco-Scale, the Analytical GREEnness metric approach, and the Blue Applicability Grade Index.
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(This article belongs to the Collection Feature Paper Collection in Section Chromatographic Separations)
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Open AccessCorrection
Correction: Saafie et al. Effect of Hydrothermal Conditions on Kenaf-Based Carbon Quantum Dots Properties and Photocatalytic Degradation. Separations 2023, 10, 137
by
Nabilah Saafie, Nonni Soraya Sambudi, Mohd Dzul Hakim Wirzal and Suriati Sufian
Separations 2024, 11(4), 118; https://doi.org/10.3390/separations11040118 - 15 Apr 2024
Abstract
There was an error in the original publication [...]
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(This article belongs to the Section Environmental Separations)
Open AccessArticle
Antioxidant and Hepatoprotective Activity of an Extract from the Overground Parts of Phlomis russeliana Lag. ex Benth
by
Magdalena Kondeva-Burdina, Aleksandar Shkondrov, Georgi Popov, Vasil Manov and Ilina Krasteva
Separations 2024, 11(4), 117; https://doi.org/10.3390/separations11040117 - 13 Apr 2024
Abstract
An evaluation of the possible hepatotoxicity/hepatoprotective effects of a defatted extract of the above ground parts of Phlomis russeliana was conducted in vitro and in vivo. The extract was tested in vitro on hepatocytes alone and in a carbon tetrachloride (CCl4)-bioactivation
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An evaluation of the possible hepatotoxicity/hepatoprotective effects of a defatted extract of the above ground parts of Phlomis russeliana was conducted in vitro and in vivo. The extract was tested in vitro on hepatocytes alone and in a carbon tetrachloride (CCl4)-bioactivation model. The same toxic substance was used for the in vivo evaluation on old Wistar rats. The extract was standardised via high performance liquid chromatography (HPLC) by the quantification of total flavonoids and verbascoside. Gallic acid equivalents were used to express the content of total phenolic compounds. The identification of flavonoids in this species was undertaken for the first time. The extract was not statistically hepatotoxic in vitro on the isolated rat hepatocytes. In the CCl4-induced hepatotoxicity model, the extract had a hepatoprotective effect, which was concentration-dependant (the highest at 50 µg/mL). An in vivo study on old rats confirmed the observed antioxidant and hepatoprotective effects. The histological findings were favourable for the rats, given the extract and CCl4 in combination. They had an unchanged organ structure, which is commensurable with these animals, treated with a combination of CCl4 and silymarin.
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(This article belongs to the Special Issue Isolation of Natural Compounds—Emphasis on Antioxidants' Purification)
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Open AccessArticle
Synthesis of Quaternary-Ammonium-Lignin-Based Ionic Liquids and Comparison of Extraction Behavior of Co(II) and Ni(II) with 2-Ethylhexyl Phosphoric Acid Mono-2-Ethylhexyl Ester
by
Guijiang Li and Wenze Xu
Separations 2024, 11(4), 116; https://doi.org/10.3390/separations11040116 - 12 Apr 2024
Abstract
The escalating demand for cobalt in modern industry necessitates the recycling or extraction of this resource for sustainable development. Despite the abundance of lignin in nature, its utilization remains low, highlighting the need to enhance its value-added potential. This study focuses on the
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The escalating demand for cobalt in modern industry necessitates the recycling or extraction of this resource for sustainable development. Despite the abundance of lignin in nature, its utilization remains low, highlighting the need to enhance its value-added potential. This study focuses on the synthesis of quaternary ammonium lignin (QAL) and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as ionic liquid (QP–IL) compounds for the extraction of metal ions. A comparison of the extraction behavior of Co(II) and Ni(II) from chloride solution between QP–IL and P507 revealed varying extraction ratios under different conditions, with QP–IL demonstrating a higher cobalt extractability than P507. Furthermore, under identical conditions, QP–IL exhibited superior Co/Ni separation performance (βCo/Ni) compared to P507. Ultimately, QP–IL proved to be more effective than P507 in separating cobalt from mixed solutions.
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(This article belongs to the Special Issue Advanced Extraction and Microextraction Techniques and Their Applications in Sample Preparation)
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Open AccessArticle
An Evaluation of Microfiltration and Ultrafiltration Pretreatment on the Performance of Reverse Osmosis for Recycling Poultry Slaughterhouse Wastewater
by
Faryal Fatima, Sana Fatima, Hongbo Du and Raghava Rao Kommalapati
Separations 2024, 11(4), 115; https://doi.org/10.3390/separations11040115 - 08 Apr 2024
Abstract
To implement sustainable water resource management, the industries that produce a huge amount of wastewater are aiming to recycle wastewater. Reverse osmosis (RO) is an advanced membrane process that can produce potable water from wastewater. However, the presence of diverse pollutants in the
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To implement sustainable water resource management, the industries that produce a huge amount of wastewater are aiming to recycle wastewater. Reverse osmosis (RO) is an advanced membrane process that can produce potable water from wastewater. However, the presence of diverse pollutants in the wastewater necessitates effective pretreatment to ensure successful RO implementation. This study evaluated the efficiency of microfiltration (MF) and ultrafiltration (UF) as two pretreatment methods prior to RO, i.e., MF-RO and UF-RO, for recycling poultry slaughterhouse wastewater (PSWW). The direct treatment of PSWW with RO (direct RO) was also considered for comparison. In this study, membrane technology serves as a post treatment for PSWW, which was conventionally treated at Sanderson Farm. The results demonstrated that all of the processes, including MF-RO, UF-RO, and direct RO treatment of PSWW, rejected 100% of total phosphorus (TP), over 91.2% of chemical oxygen demand (COD), and 87% of total solids (TSs). Total nitrogen (TN) levels were reduced to 5 mg/L for MF-RO, 4 mg/L for UF-RO, and 9 mg/L for direct RO. In addition, the pretreatment of PSWW with MF and UF increased RO flux from 46.8 L/m2 h to 51 L/m2 h, an increase of approximately 9%. The product water obtained after MF-RO, UF-RO, and direct RO meets the required potable water quality standards for recycling PSWW in the poultry industry. A cost analysis demonstrated that MF-RO was the most economical option among membrane processes, primarily due to MF operating at a lower pressure and having a high water recovery ratio. In contrast, the cost of using RO without MF and UF pretreatments was approximately 2.6 times higher because of cleaning and maintenance expenses related to fouling. This study concluded that MF-RO is a preferable option for recycling PSWW. This pretreatment method would significantly contribute to environmental sustainability by reusing well-treated PSWW for industrial poultry purposes while maintaining cost efficiency.
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(This article belongs to the Section Purification Technology)
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