Separations

14 pages, 2897 KiB

Open AccessArticle

Kinetic Study and Process Optimization of Plutonium Barrier Units for Enhanced Plutonium Stripping in the PUREX Process

by Haowei Zhu, Qi Chen, Chen Zuo, Tianchi Li, Jieqiong Yuan, Ziqian Zhao, Taihong Yan and Weifang Zheng

Separations 2024, 11(9), 278; https://doi.org/10.3390/separations11090278 - 23 Sep 2024

Viewed by 467

Abstract

In the PUREX (the plutonium uranium reduction extraction) process, a plutonium barrier unit (1BXX) is used to achieve deep plutonium stripping. According to the operating experience of the French reprocessing plant, after the separation of uranium and plutonium in the first cycle (1B [...] Read more.

In the PUREX (the plutonium uranium reduction extraction) process, a plutonium barrier unit (1BXX) is used to achieve deep plutonium stripping. According to the operating experience of the French reprocessing plant, after the separation of uranium and plutonium in the first cycle (1B + 1BXX), the plutonium barrier unit has excellent stripping effect, such that the removal of plutonium from uranium can already be achieved in the first cycle, and the second cycle only needs to focus on the removal of neptunium from uranium in order to obtain a qualified uranium product. In recent decades, China has also been actively conducting research on the plutonium barrier unit process to reduce the plutonium concentration in the primary uranium product in the first cycle to avoid the need to remove neptunium and plutonium at the same time in the second cycle, and to improve the efficiency and feasibility of reprocessing. Due to the lack of design basis for plutonium barriers to achieve deep plutonium stripping at present, this study conducts a basic study on the plutonium barrier unit, aiming to provide data for the optimization of plutonium barriers in the actual reprocessing process at a later date. In this work, a kinetic study on the reduction and stripping of trace plutonium from dibutyl phosphate-containing organic phases was carried out first, and the kinetic equations for the reduction and stripping of Pu(IV) by U(IV) under flow process conditions were obtained. The effects of U(IV) addition on the extraction loss of U(IV) and the concentration distribution of U(IV) at various stages were investigated by process simulation. Additionally, the oxidation of U(IV) under process conditions was investigated to clarify the process chemistry of U(IV) oxidation and to provide a reference for the oxidation consumption of U(IV). Finally, the process parameters of the plutonium barrier unit were preliminarily designed based on the above research. Full article

(This article belongs to the Special Issue Research on New Technology and Equipment of Multiphase Flow Separation)

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13 pages, 5851 KiB

Open AccessArticle

High-Efficiency Selective Adsorption of Rubidium and Cesium from Simulated Brine Using a Magnesium Ammonium Phosphate Adsorbent

by Haining Liu, Yanping Wang, Qiongyuan Zhang, Wenjie Han, Huifang Zhang and Xiushen Ye

Separations 2024, 11(9), 277; https://doi.org/10.3390/separations11090277 - 23 Sep 2024

Viewed by 587

Abstract

Rubidium and cesium are critical strategic elements, and their development and utilization are of great significance. In this study, a magnesium ammonium phosphate (MAP) adsorbent was prepared and characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, and [...] Read more.

Rubidium and cesium are critical strategic elements, and their development and utilization are of great significance. In this study, a magnesium ammonium phosphate (MAP) adsorbent was prepared and characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, and Fourier transform infrared spectroscopy (FTIR). The adsorption performance of the adsorbent for Rb⁺ and Cs⁺ in solution was investigated. The results showed that the adsorbent exhibited high adsorption capacities of 2.83 mol/g for Rb⁺ and 4.37 mol/g for Cs⁺. In simulated brine, the adsorbent demonstrated excellent selectivity for Cs⁺. Kinetic and thermodynamic studies indicated that the adsorption process followed a pseudo-second order kinetic model and Langmuir isotherm model. The primary adsorption mechanism was an ion exchange. The development of this adsorbent holds significant promise for the extraction of rubidium and cesium from liquid resources. Full article

(This article belongs to the Special Issue Green and Efficient Separation and Extraction of Salt Lake Resources)

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16 pages, 1893 KiB

Open AccessArticle

Development of a QAMS Analysis Method for Industrial Lanolin Alcohol Based on the Concept of Analytical Quality by Design

by Kaidierya Abudureheman, Qinglin Wang, Hao Zhang and Xingchu Gong

Separations 2024, 11(9), 276; https://doi.org/10.3390/separations11090276 - 22 Sep 2024

Viewed by 757

Abstract

The Analytical Quality by Design (AQbD) concept was adopted to establish a quantitative analysis of multi-components with a single marker (QAMS) method for industrial lanolin alcohol, targeting cholesterol, lanosterol, and 24,25-dihydrolanosterol. The potential critical method parameters (CMPs) were identified as column temperature, flow [...] Read more.

The Analytical Quality by Design (AQbD) concept was adopted to establish a quantitative analysis of multi-components with a single marker (QAMS) method for industrial lanolin alcohol, targeting cholesterol, lanosterol, and 24,25-dihydrolanosterol. The potential critical method parameters (CMPs) were identified as column temperature, flow rate, and gradient. Definitive screening design and statistical modeling were employed to optimize the gradient conditions of the mobile phase, column temperature, and flow rate. The Method Operable Design Region (MODR) was determined using a risk-based quantification approach. The robustness was assessed using a Plackett–Burman experimental design, followed by methodological validation. Optimal analytical conditions were as follows: acetonitrile (B)—water (A) mobile phase system; flow rate of 1.58 mL/min; detection wavelength of 205 nm; injection volume of 10 µL; and column temperature of 37 °C. A gradient elution program was implemented as follows: 0–19.0 min, 90.5% B; 19.0–25.0 min, 90.5–100% B; and 25.0–55.0 min, 100% B. Cholesterol served as an internal standard for quantifying lanosterol and 24,25-dihydrolanosterol, with relative correction factors of 0.4227 and 0.8228, respectively. This analytical method utilized only the cholesterol reference substance as an internal standard to quantify the content of cholesterol, lanosterol, and 24,25-dihydrolanosterol in industrial lanolin alcohol. It reduced the testing costs and enhanced efficiency, making it potentially suitable for widespread adoption in lanolin alcohol processing industries. Full article

(This article belongs to the Special Issue The 10th Anniversary of Separations: Advances in Separation and Analysis of Natural Products/Medicines)

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16 pages, 3287 KiB

Open AccessArticle

Assessment of the Antioxidant Potential of Blackthorns and Hawthorns: Comparative Analysis and Potential Use in Ruminants’ Nutrition

by Alexandra-Gabriela Oancea, Mihaela Saracila, Petru Alexandru Vlaicu, Iulia Varzaru, Arabela Elena Untea and Catalin Dragomir

Separations 2024, 11(9), 275; https://doi.org/10.3390/separations11090275 - 22 Sep 2024

Viewed by 552

Abstract

The food industry is intensifying its effort to enrich food composition in various nutrients through animal feeding, but these challenges can be limited by the costly feed resources, water scarcity, and pesticide pollution, making it crucial to explore alternative feedstuffs with fewer requirements. [...] Read more.

The food industry is intensifying its effort to enrich food composition in various nutrients through animal feeding, but these challenges can be limited by the costly feed resources, water scarcity, and pesticide pollution, making it crucial to explore alternative feedstuffs with fewer requirements. Blackthorns and hawthorns are characterized by their rich phytochemical and antioxidant profiles, suggesting their potential to enhance the performance of ruminants though the supply of bioactive substances. Our study revealed their rich composition of micronutrients; hawthorns showed a remarkable amount of polyunsaturated fatty acids (57.23 g FAME/100 g total FAME), particularly omega-3 and omega-6, while blackthorn presented higher concentration of monounsaturated fatty acids, specifically oleic acid (56.99 g FAME/100 g total FAME). In terms of lipo-soluble antioxidants, blackthorn exhibited higher levels of xanthophyll and vitamin E (123.83 mg/kg DM), including its isomers (alpha, gamma, and delta). Concerning the water-soluble antioxidants, hawthorns showed elevated composition of the total content of flavonoids and polyphenols, comparing with blackthorn. Moreover, hawthorns showed a high antioxidant capacity, as assessed through DPPH, ABTS, and TAC analyses. In terms of the scavenging capacity of blackthorn and hawthorn against superoxide radicals, blackthorn had higher radical scavenging potential against superoxide radicals, compared to hawthorn. Full article

(This article belongs to the Special Issue Isolation and Identification of Biologically Active Natural Compounds)

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15 pages, 3796 KiB

Open AccessArticle

Visible Light-Assisted Periodate Activation Using Carbon Nitride for the Efficient Elimination of Acid Orange 7

by Wenjun Xu, Qianyi Wang, Jintao He, Fuzhen Liu, Xiang Yan and Yin Xu

Separations 2024, 11(9), 274; https://doi.org/10.3390/separations11090274 - 19 Sep 2024

Viewed by 731

Abstract

The development of appropriate and effective periodate (PI) activation technology is currently a popular research area. This study presents a novel efficient photocatalytic activation approach of PI for pollutant degradation based on carbon nitride (g-C₃N₄) and visible light (Vis). [...] Read more.

The development of appropriate and effective periodate (PI) activation technology is currently a popular research area. This study presents a novel efficient photocatalytic activation approach of PI for pollutant degradation based on carbon nitride (g-C₃N₄) and visible light (Vis). The results show that the system can remove 92.3% of acid orange 7 (AO7) within 60 min under the g-C₃N₄/PI/Vis reaction system. The degradation rate constant (k_obs) reached 4.08 × 10⁻² min⁻¹, which is 4.21, 5.16 times, and 51.3 times higher than that of the g-C₃N₄/Vis system (9.7 × 10⁻³ min⁻¹), PI/Vis system (7.9 × 10⁻³ min⁻¹) and the g-C₃N₄/PI system (7.96 × 10⁻⁴ min⁻¹), respectively. Clearly, the addition of PI significantly enhances the degradation efficiency of AO7 in the system. Additionally, under the same reaction conditions, the presence of PI showed excellent oxidation capacity in the photoactivation process compared with other common oxidants, such as peroxymonosulfate, peroxydisulfate, and H₂O₂. Moreover, the g-C₃N₄/PI/Vis system showed excellent removal of AO7 across a wide range of pH levels and in the presence of various anions. Electron paramagnetic resonance (EPR) and quenching experiments suggested that the superoxide anions (^•O₂⁻) and singlet oxygen (¹O₂) dominated in the oxidation of pollutants in the g-C₃N₄/PI/Vis system. In addition, the catalyst showed relative stability during cyclic testing, although a slight reduction in degradation efficiency was observed. In brief, the g-C₃N₄/PI/Vis system is highly efficient and environmentally friendly, with significant application potential in wastewater treatment. Full article

(This article belongs to the Special Issue High-Efficiency Catalyst Preparation and Application in Environmental Purification)

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14 pages, 5069 KiB

Open AccessArticle

Optimizing Vertical Zone Refining for Ultra-High-Purity Tin: Numerical Simulations and Experimental Analyses

by Yu Yao, Jiajun Wen, Qi He, Meizhen Wu, Lishi Chen, Yuxu Bao and Hongxing Zheng

Separations 2024, 11(9), 273; https://doi.org/10.3390/separations11090273 - 19 Sep 2024

Viewed by 593

Abstract

This study investigates the application of the vertical zone refining process to produce ultra-high-purity tin. Computational fluid dynamics (CFD) simulations were conducted using an Sn-1 wt.%Bi binary alloy to assess the effects of two key parameters—heater temperature and pulling rate—on Bi impurity segregation. [...] Read more.

This study investigates the application of the vertical zone refining process to produce ultra-high-purity tin. Computational fluid dynamics (CFD) simulations were conducted using an Sn-1 wt.%Bi binary alloy to assess the effects of two key parameters—heater temperature and pulling rate—on Bi impurity segregation. The simulations revealed a dynamic evolution in molten zone height, characterized by an initial rapid rise, followed by a gradual increase and ending with a sharp decline. Despite these fluctuations, the lower solid–liquid interface consistently remained slightly convex. After nine zone passes, impurities accumulated at the top of the sample, with dual vortices forming a rhombus- or gate-shaped negative segregation zone. The simulations demonstrated that lower heater temperatures and slower pulling rates enhanced impurity segregation efficiency. Based on these results, experiments were performed using 6N-grade tin as the starting material. Glow discharge mass spectrometry (GDMS) analysis showed that the effective partition coefficients (k_eff) for impurities such as Ag, Pb, Co, Al, Bi, Cu, Fe, and Ni were significantly less than 1, while As was slightly below but very close to 1, and Sb was above 1. Under optimal conditions—405 °C heater temperature and a pulling rate of 5 μm/s—over 60% of impurities were removed after nine zone passes, approaching 6N9-grade purity. These findings provide valuable insights into optimizing the vertical zone refining process and demonstrate its potential for achieving 7N-grade ultra-high-purity tin. Full article

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12 pages, 1543 KiB

Open AccessArticle

Photocatalytic Degradation of Levofloxacin and Inactivation of Enterococci Levofloxacin-Resistant Bacteria Using Pure Rare-Earth Oxides

by Lorenzo Saviano, Antonietta Mancuso, Alice Cardito, Olga Sacco, Vincenzo Vaiano, Maurizio Carotenuto, Giovanni Libralato and Giusy Lofrano

Separations 2024, 11(9), 272; https://doi.org/10.3390/separations11090272 - 18 Sep 2024

Viewed by 447

Abstract

In this study, La₂O₃ and CeO₂ nanopowders were prepared using a simple and cost-effective precipitation method. Wide-angle X-ray diffraction (WAXD), UV-Visible reflectance diffuses (UV-Vis DRS), Raman spectroscopy, and specific surface area were used to characterize the photocatalysts, evidencing that [...] Read more.

In this study, La₂O₃ and CeO₂ nanopowders were prepared using a simple and cost-effective precipitation method. Wide-angle X-ray diffraction (WAXD), UV-Visible reflectance diffuses (UV-Vis DRS), Raman spectroscopy, and specific surface area were used to characterize the photocatalysts, evidencing that the used preparation method was effective in the generation of crystalline CeO₂ and La₂O₃. In particular, WAXD results showed that the average crystallite size of the achieved La₂O₃ and CeO₂ samples were about 22 nm and 28 nm, respectively. The photocatalytic performances of the prepared catalysts were investigated in the degradation of levofloxacin (LEV) and the inactivation of a waterborne pathogen levofloxacin resistant (Enterococcus faecalis ATCC 29212) by using a photoreactor equipped with a solar simulator (SS). After 120 min, the CeO₂ and La₂O₃ photocatalytic treatments allowed us to achieve between 75% and 83% of levofloxacin removal, respectively. A complete removal of 10⁶ CFU/mL Enterococcus faecalis ATCC 29212 was achieved after 5 and 60 min of La₂O₃ and CeO₂ photocatalytic processes, respectively. Full article

(This article belongs to the Special Issue Photocatalytic Materials for Pollutant Removal by Degradation)

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18 pages, 3717 KiB

Open AccessArticle

The Optimization of the Osborne Extraction Method for the Fractionation and Characterization of Oat Proteins

by Sorel Tchewonpi Sagu, Lara Talea Wiedemann, Kapil Nichani, Andrea Henze and Harshadrai M. Rawel

Separations 2024, 11(9), 271; https://doi.org/10.3390/separations11090271 - 17 Sep 2024

Cited by 1 | Viewed by 879

Abstract

The growing number of wheat-related allergies worldwide has resulted in a new trend towards gluten-free alternatives. In this context, alternative cereals such as sorghum and oats are attracting new interest. Given the limited data available, the question of whether these cereals are completely [...] Read more.

The growing number of wheat-related allergies worldwide has resulted in a new trend towards gluten-free alternatives. In this context, alternative cereals such as sorghum and oats are attracting new interest. Given the limited data available, the question of whether these cereals are completely safe and gluten-free for allergy sufferers remains open. One of the key steps in protein research is their efficient extraction. In this work, the Osborne sequential extraction method was developed and optimized using the response surface methodology in order to fractionate oat proteins. An optimized desirability of 0.986 was achieved with an extraction time of 4.7 min, a speed of 6, and a sample/solvent ratio of 5. The corresponding optimized responses were 8.7, 4.0, and 5.1% for the extraction yields of the avenin, avenalin, and albumin/globulin fractions, respectively. Further characterization of the extracts was carried out on 24 homogeneous and commercial oat samples via LC-MS/MS, targeting six potentially allergenic proteins. The avenin-E protein featured prominently, with relative contents of 60.7, 32.2, 58.0, and 59.8% in the total extract, avenin, avenalin, and albumin/globulin fractions, respectively, while the Avenin-3, ATI-2, avenin, SSG2, and SSG1 proteins in the total extract showed levels of 16.4, 9.3, 6.6, 4.8, and 2.2%, respectively. The preliminary results of an ELISA performed on the different fractions revealed low levels of gluten (from 1.24 ± 0.14 to 3.61 ± 0.16 mg/kg), which were well below the threshold limit of 20 mg/kg. These results support the hypothesis that oats can be a safe food for people suffering from cereal-related allergies. These results open the door to further studies into the comprehensive characterization of oat proteins. Full article

(This article belongs to the Special Issue Extraction and Analysis of Chemical Composition from Natural Products and Metabolites)

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10 pages, 7573 KiB

Open AccessCommunication

Rapid Purification and Quantification of Intestinal and Fecal Short-Chain Fatty Acids by Solid-Phase Extraction Using Bond Elut Plexa

by Xing Zheng, Tao Chen, Wanli Li, Kai Wang, Xiaofeng Xue, Nenad Naumovski and Wenjun Peng

Separations 2024, 11(9), 270; https://doi.org/10.3390/separations11090270 - 16 Sep 2024

Viewed by 961

Abstract

Short-chain fatty acids (SCFAs) in feces are inextricably linked to intestinal homeostasis and can be used as potential markers for metabolic diseases. In this study, an efficient and simple method was developed for the purification of SCFAs without the need for derivatization of [...] Read more.

Short-chain fatty acids (SCFAs) in feces are inextricably linked to intestinal homeostasis and can be used as potential markers for metabolic diseases. In this study, an efficient and simple method was developed for the purification of SCFAs without the need for derivatization of the samples. The SCFAs (acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic acid) were extracted from a small amount (50 mg) of fecal and intestinal samples using acetone combined with solid phase extraction column (Bond Elut Plexa) enrichment. Quantitative analysis was performed using gas chromatography with a flame ionization detector. The developed method has shown very good limits of detection (LOD, 0.11–0.36 μM) and limits of quantification (LOQ, 0.38–1.21 μM) with excellent linearity (R² ≥ 0.9998), good recovery (98.34–137.83%), and high reproducibility (RSD ≤ 1.30). The applicability of this method was also demonstrated by testing the fecal and cecum contents of different species from mammals (mice, pigs) to insects (honeybees). The technique is highly suitable for analyzing complex, small amounts of intestinal and fecal SCFAs. Full article

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15 pages, 2581 KiB

Open AccessArticle

Multi-Residue Analysis of Thyreostats in Animal Muscle Tissues by Hydrophilic Interaction Liquid Chromatography Tandem Mass Spectrometry: A Thorough Chromatographic Study

by Anastasia S. Kritikou, Marilena E. Dasenaki, Niki C. Maragou, Marios G. Kostakis and Nikolaos S. Thomaidis

Separations 2024, 11(9), 269; https://doi.org/10.3390/separations11090269 - 14 Sep 2024

Viewed by 526

Abstract

Τhyreostats (TSs) are veterinary drugs used in livestock farming for fattening. Their administration is banned in the European Union since 1981, and their monitoring for food quality and safety control requires sensitive and confirmatory methods. The present study describes the development and validation [...] Read more.

Τhyreostats (TSs) are veterinary drugs used in livestock farming for fattening. Their administration is banned in the European Union since 1981, and their monitoring for food quality and safety control requires sensitive and confirmatory methods. The present study describes the development and validation of a hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) method for the simultaneous determination of 2-thiouracil (TU), 6-methyl-2-thiouracil (MTU), 6-propyl-2-thiouracil (PTU), 6-phenyl-2-thiouracil (PhTU), tapazole (TAP), and 2-mercaptobenzimidazole (MBI) in bovine muscle tissues. Investigation of the retention mechanism of the six analytes on the selected amide-based stationary phase showed that hydrophilic partition was the dominant interaction. The sample preparation included extraction with ACN/H₂O (80/20), followed by dispersive solid-phase extraction (d-SPE) with C18 sorbent and hexane partitioning. The method was validated according to European guidelines using internal standards, including isotopically labelled ones. The method’s LODs ranged between 2.8 ng g⁻¹ (6-phenyl-2-thiouracil) and 4.1 ng g⁻¹ (2-thiouracil). Application of the proposed method to 48 bovine tissue samples showed non-detectable results. Full article

(This article belongs to the Special Issue Emerging Analytical Methods for Detection and Separation of Environmental Pollutants and Food Contaminants)

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12 pages, 2065 KiB

Open AccessArticle

Simultaneously Tuning Charge Separation and Surface Reaction Kinetics on ZnIn₂S₄ Photoanode by P-Doping for Highly Efficient Photoelectrochemical Water Splitting and Urea Oxidation

by Jiamin Sun, Ling Tang, Chenglong Li, Jingjing Quan, Li Xu, Xingming Ning, Pei Chen, Qiang Weng, Zhongwei An and Xinbing Chen

Separations 2024, 11(9), 268; https://doi.org/10.3390/separations11090268 - 13 Sep 2024

Cited by 1 | Viewed by 606

Abstract

ZnIn₂S₄ nanosheets are a promising photoanode for driving photoelectrochemical (PEC) hydrogen fuel production; nevertheless, poor charge separation and sluggish surface reaction kinetics hinder its PEC performance to an extreme degree. Herein, a facile element doping strategy (i.e., P element) was [...] Read more.

ZnIn₂S₄ nanosheets are a promising photoanode for driving photoelectrochemical (PEC) hydrogen fuel production; nevertheless, poor charge separation and sluggish surface reaction kinetics hinder its PEC performance to an extreme degree. Herein, a facile element doping strategy (i.e., P element) was developed to obtain the desired photoanode. As a result, the ZnIn₂S₄-P (ZIS-P₅) photoanode exhibits a remarkable photocurrent density of 1.66 mA cm⁻² at 1.23 V versus a reversible hydrogen electrode (V_RHE) and a much lower onset potential of 0.12 V vs. RHE for water oxidation. Careful electrochemical analysis confirms that the P doping and sulfur vacancies (Sv) not only facilitate the hole transfer, but also boost surface reaction kinetics. Finally, the “killing two birds with one stone” goal can be achieved. Moreover, the optimized photoanode also presents high PEC performance for urea oxidation, obtaining a photocurrent density of 4.13 mA cm⁻² at 1.23 V vs. RHE. This work provides an eco-friendly, simple and effective method to realize highly efficient solar-to-hydrogen conversion. Full article

(This article belongs to the Section Separation Engineering)

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21 pages, 4592 KiB

Open AccessArticle

Experimental Study on Vehicle Pressure Swing Adsorption Oxygen Production Process Based on Response Surface Methodology

by Ye Li, Lisheng Zhao, Shuguang Li, Jianqiu Bei, Haotu Zhong, Yingshu Liu, Quanli Zhang, Ningqi Sun, Ziyi Li, Shifeng Wang and Xiong Yang

Separations 2024, 11(9), 267; https://doi.org/10.3390/separations11090267 - 11 Sep 2024

Viewed by 602

Abstract

In recent years, the number of people driving from plain areas to the western plateau of China has been increasing, and their safety is threatened by acute high-altitude reactions caused by hypoxia. Vehicle-mounted pressure swing adsorption oxygen supply technology can help solve this [...] Read more.

In recent years, the number of people driving from plain areas to the western plateau of China has been increasing, and their safety is threatened by acute high-altitude reactions caused by hypoxia. Vehicle-mounted pressure swing adsorption oxygen supply technology can help solve this problem. For the optimization of vehicle pressure swing adsorption oxygen production, the influence of different pressure equalization methods on oxygen production efficiency was studied. The best oxygen production performance was achieved when the initial upper pressure equalization method and the simultaneous pressure equalization method were used. Using a 160 W air compressor, the product gas flow rate could reach 2.5 L/min with an oxygen concentration of 93.48%. The impact of adsorption time, equalization time, flow rate, and throttle inner diameter on oxygen concentration and recovery rate was analyzed using the response surface method. The order of the four factors affecting oxygen concentration is as follows: flow rate > adsorption time > equalization time > throttle inner diameter. After optimization, the product gas flow rate was 2.6 L/min, the oxygen concentration was 92.11%, and the oxygen recovery rate was 44.51%. Full article

(This article belongs to the Special Issue Recent Advances in Gas Separation and Purification)

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21 pages, 1122 KiB

Open AccessArticle

HS-SPME-GC-MS Analysis of the Volatile Composition of Italian Honey for Its Characterization and Authentication Using the Genetic Algorithm

by Carlotta Breschi, Francesca Ieri, Luca Calamai, Alessandra Miele, Silvia D’Agostino, Fabrizio Melani, Bruno Zanoni, Nadia Mulinacci and Lorenzo Cecchi

Separations 2024, 11(9), 266; https://doi.org/10.3390/separations11090266 - 10 Sep 2024

Viewed by 781

Abstract

Honey’s chemical and sensory characteristics depend on several factors, including its botanical and geographic origins. The consumers’ increasing interest in monofloral honey and honey with a clear indication of geographic origin make these types of honey susceptible to fraud. The aim was to [...] Read more.

Honey’s chemical and sensory characteristics depend on several factors, including its botanical and geographic origins. The consumers’ increasing interest in monofloral honey and honey with a clear indication of geographic origin make these types of honey susceptible to fraud. The aim was to propose an original chemometric approach for honey’s botanical and geographic authentication purposes. The volatile fraction of almost 100 Italian honey samples (4 out of which are from Greece) from different regions and botanical origins was characterized using HS-SPME-GC-MS; the obtained data were combined for the first time with a genetic algorithm to provide a model for the simultaneous authentication of the botanical and geographic origins of the honey samples. A total of 212 volatile compounds were tentatively identified; strawberry tree honeys were those with the greatest total content (i.e., 4829.2 ng/g). A greater variability in the VOCs’ content was pointed out for botanical than for geographic origin. The genetic algorithm obtained a 100% correct classification for acacia and eucalyptus honeys, while worst results were achieved for honeydew (75%) and wildflower (60%) honeys; concerning geographic authentication, the best results were for Tuscany (92.7%). The original combination of HS-SPME-GC-MS analysis and a genetic algorithm is therefore proposed as a promising tool for honey authentication purposes. Full article

(This article belongs to the Special Issue Determination and Analysis of Volatiles by Solid Phase Microextraction, GC-MS, LC-MS and HPLC)

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15 pages, 1292 KiB

Open AccessArticle

Determining Carbohydrates for Increasing Safety: GC-FID Quantification of Lactose, Galactose, Glucose, Tagatose and Myo-Inositol in ‘Maturo’ PDO Pecorino Sardo Cheese

by Alessio Silvio Dedola, Marco Caredda, Margherita Addis, Giacomo Lai, Myriam Fiori, Massimo Pes, Andrea Mara and Gavino Sanna

Separations 2024, 11(9), 265; https://doi.org/10.3390/separations11090265 - 9 Sep 2024

Viewed by 846

Abstract

Although PDO Pecorino Sardo is one of the oldest traditional cheeses of Sardinia, Italy, data on its nutritional properties and food safety are lacking. In particular, significant amounts of lactose and galactose may be a health concern for consumers. The primary objective of [...] Read more.

Although PDO Pecorino Sardo is one of the oldest traditional cheeses of Sardinia, Italy, data on its nutritional properties and food safety are lacking. In particular, significant amounts of lactose and galactose may be a health concern for consumers. The primary objective of this study is to quantify, using a validated GC-FID method, the residual lactose and galactose content in “maturo” (i.e., ripened for at least two months) Protected Denomination of Origin (PDO) Pecorino Sardo cheese. A statistically representative sampling from seven dairies distributed throughout Sardinia has been selected for this aim. In addition to lactose and galactose, two of their metabolites (i.e., glucose and tagatose, respectively) and a bioactive polyol like myo-inositol were quantified. The concentration of lactose (mean 26 mg kg⁻¹, range 4–90 mg kg⁻¹) was below the strictest limit set in the European Union (i.e., 100 mg kg⁻¹), while the galactose content was found to be in an amount (mean: 76 mg kg⁻¹, range: 10–200 mg kg⁻¹) that even patients afflicted with severe galactosemia, albeit with some circumspection, could consume this cheese. Ripening (two to four months) had no significant effect on the amount of all analytes, while a slight decrease in galactose levels was observed during the manufacturing season. Finally, the amounts of glucose, tagatose, and myo-inositol are constant in the range of a few tens of mg kg⁻¹. Full article

(This article belongs to the Special Issue 10th Anniversary of Separations: Recent Advances in Analysis of Food and Beverages)

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13 pages, 1880 KiB

Open AccessArticle

Screening Biogenic Volatile Organic Compounds from Common Portuguese Shrubs Using Headspace–Bar Adsorptive Microextraction (HS-BAµE)

by Jéssica S. R. F. Cerqueira and José M. F. Nogueira

Separations 2024, 11(9), 264; https://doi.org/10.3390/separations11090264 - 9 Sep 2024

Viewed by 766

Abstract

In this study, headspace–bar adsorptive microextraction (HS-BAµE) combined with gas chromatography–mass spectrometry (GC-MS) was employed to screen the major biogenic volatile organic compounds (BVOCs) emitted by six different Portuguese shrub species (Erica scoparia L., Cistus ladanifer L., Cistus monspeliensis L., Lavandula stoechas [...] Read more.

In this study, headspace–bar adsorptive microextraction (HS-BAµE) combined with gas chromatography–mass spectrometry (GC-MS) was employed to screen the major biogenic volatile organic compounds (BVOCs) emitted by six different Portuguese shrub species (Erica scoparia L., Cistus ladanifer L., Cistus monspeliensis L., Lavandula stoechas L., Thymus villosus L., and Thymus camphoratus). The HS-BAµE/GC-MS methodology was developed, optimized, and validated using five common monoterpenoids (α-pinene, β-pinene, limonene, 1,8-cineole, and thymol) and one sesquiterpenoid (caryophyllene oxide). Under optimized experimental conditions (microextraction-sorbent phase: activated carbon (CN1), 3 h (35 °C); back-extraction: n-C₆ (1 h)), good efficiencies (>45%), low analytical thresholds (5.0–15.0 µg/L) and suitable linear dynamic ranges (20.0–120.0 µg/L, r² > 0.9872) were achieved, as well as acceptable intra and inter-day precisions (RSD ≤ 30.1%). Benchmarking the proposed methodology, HS-BAµE(CN1), against the reference methodology, HS-SPME(PDMS/DVB), revealed comparable analytical responses and demonstrated excellent reproducibility. Among the six shrub species studied, Thymus camphoratus exhibited the highest emissions of BVOCs from its leaves, notably, 1,8-cineole (4136.9 ± 6.3 µg/g), α-pinene (763.9 ± 0.5 µg/g), and β-pinene (259.3 ± 0.5 µg/g). It was also the only species found to release caryophyllene oxide (411.4 ± 0.3 µg/g). The observed levels suggest that these shrub species could potentially serve as fuel sources in the event of forest fires occurring under extreme conditions. In summary, the proposed methodology proved to be a favorable analytical alternative for screening BVOCs in plants. It not only exhibited remarkable performance but also demonstrated user- and eco-friendliness, cost-effectiveness, and ease of implementation. Full article

(This article belongs to the Special Issue Extraction and Analysis of Chemical Composition from Natural Products and Metabolites)

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12 pages, 1706 KiB

Open AccessArticle

In Vitro and In Silico Anticyclooxygenase and Antitopoisomerase Activity of Anonna cherimola Ent-Kaurenes

by Carlos Eduardo Camacho-González, Alejandro Pérez-Larios, Sonia G. Sáyago-Ayerdi, Jasmin Salazar-Mendoza and Jorge A. Sánchez-Burgos

Separations 2024, 11(9), 263; https://doi.org/10.3390/separations11090263 - 6 Sep 2024

Viewed by 692

Abstract

Annona cherimola is noted for its bioactive compounds, particularly diterpenes called ent-kaurenes, which exhibit various biological activities. This study focused on evaluating the ability of ent-kaurenes from Annona cherimola to inhibit cyclooxygenase (COX) and topoisomerase (TOP) enzymes. Researchers used solvent-free lipophilic eluates (SFLEs) [...] Read more.

Annona cherimola is noted for its bioactive compounds, particularly diterpenes called ent-kaurenes, which exhibit various biological activities. This study focused on evaluating the ability of ent-kaurenes from Annona cherimola to inhibit cyclooxygenase (COX) and topoisomerase (TOP) enzymes. Researchers used solvent-free lipophilic eluates (SFLEs) from the plant in enzymatic assays and a yeast model. The major compounds in SFLE were identified using gas chromatography–mass spectrometry (GC-MS), and in silico studies explored their inhibition mechanisms. SFLE showed significant inhibition of COX-II (95.44%) and COX-I (75.78%) enzymes and fully inhibited the yeast strain. The effectiveness of inhibition is attributed to the compounds’ structural diversity, lipophilicity, and molecular weight. Two main compounds, kauran-16-ol and isopimaral, were identified, with in silico results suggesting that they inhibit COX-II by blocking peroxidase activity and COX-I by interacting with the membrane-binding region. Additionally, these compounds allosterically and synergistically inhibit TOP-II and potentially sensitize cancer cells by interacting with key amino acids. This research is the first to identify and evaluate kauran-16-ol and isopimaral in silico, suggesting their potential as anti-inflammatory and anticancer agents. Full article

(This article belongs to the Special Issue Advanced Research on Extraction and Analysis of Plant Extracts)

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16 pages, 5675 KiB

Open AccessArticle

A Facile and Efficient Protocol for Phospholipid Enrichment in Synovial Joint Fluid: Monodisperse-Mesoporous SiO₂ Microspheres as a New Metal Oxide Affinity Sorbent

by Serhat Aladağ, İlayda Demirdiş, Burcu Gökçal Kapucu, Emine Koç, Ozan Kaplan, Batuhan Erhan Aktaş, Mustafa Çelebier, Ali Tuncel and Feza Korkusuz

Separations 2024, 11(9), 262; https://doi.org/10.3390/separations11090262 - 5 Sep 2024

Viewed by 853

Abstract

Phospholipids (PLs), essential components of cell membranes, play significant roles in maintaining the structural integrity and functionality of joint tissues. One of the main components of synovial joint fluid (SJF) is PLs. Structures such as PLs that are found in low amounts in [...] Read more.

Phospholipids (PLs), essential components of cell membranes, play significant roles in maintaining the structural integrity and functionality of joint tissues. One of the main components of synovial joint fluid (SJF) is PLs. Structures such as PLs that are found in low amounts in biological fluids may need to be selectively enriched to be analyzed. Monodisperse-mesoporous SiO₂ microspheres were synthesized by a multi-step hydrolysis condensation method for the selective enrichment and separation of PLs in the SJF. The microspheres were characterized by SEM, XPS, XRD, and BET analyses. SiO₂ microspheres had a 161.5 m²/g surface area, 1.1 cm³/g pore volume, and 6.7 nm pore diameter, which were efficient in the enrichment of PLs in the SJF. The extracted PLs with sorbents were analyzed using Q-TOF LC/MS in a gradient elution mode with a C18 column [2.1 × 100 mm, 2.5 μM, Xbridge Waters (Milford, MA, USA)]. An untargeted lipidomic approach was performed, and the phospholipid enrichment was successfully carried out using the proposed solid-phase extraction (SPE) protocol. Recovery of the SPE extraction of PLs using sorbents was compared to the classical liquid–liquid extraction (LLE) procedure for lipid extraction. The results showed that monodisperse-mesoporous SiO₂ microspheres were eligible for selective enrichment of PLs in SJF samples. These microspheres can be used to identify PLs changes in articular joint cartilage (AJC) in physiological and pathological conditions including osteoarthritis (OA) research. Full article

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14 pages, 1681 KiB

Open AccessArticle

Prediction of Flavor Potential of Ocimum basilicum L. Side-Stream Phytoconstituents, Using Liquid Chromatography–Tandem Mass Spectrometry Analysis and In Silico Techniques

by Eftichia Kritsi, Thalia Tsiaka, Anna Boroboka, Garyfallia Koletsou, Spyridon Theofilatos, Artemis Maggenaki, Paris Christodoulou, Georgia Ladika, Konstantinos Tsiantas, Georgios Sotiroudis and Vassilia J. Sinanoglou

Separations 2024, 11(9), 261; https://doi.org/10.3390/separations11090261 - 3 Sep 2024

Viewed by 728

Abstract

Although post-distillation side-streams of basil (Ocimum basilicum L.) pose significant economic and environmental challenges, they also bring forth new opportunities in the flavor industry. Thus, the objective of the current study was to assess the phenolic profile of basil side-stream extracts to [...] Read more.

Although post-distillation side-streams of basil (Ocimum basilicum L.) pose significant economic and environmental challenges, they also bring forth new opportunities in the flavor industry. Thus, the objective of the current study was to assess the phenolic profile of basil side-stream extracts to identify key compounds and to evaluate their taste properties, using liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis, flavor prediction tools and molecular docking. In particular, 52 phytoconstituents, mainly phenolic acids, salvianolic acids, flavonoids and fatty acids derivatives, were elucidated in the side-streams of two different basil varieties (Minimum and Genovese) harvested and distilled in early and late autumn, highlighting the effect of pre-harvest factors on basil’s phenolic fingerprint. Furthermore, the results of tests undertaken using taste prediction tools showed that most of the identified compounds were very likely to taste bitter, while six of them (caffeoylferuloyltartaric acid, isoquercetin, lithospermic acid A, sagerinic acid, salvianolic acids C and F) presented a high bitterant capacity (70–90%). Moreover, according to molecular docking studies, these compounds exhibited a stronger binding affinity to the hTAS2R46 bitter receptor compared to its known agonist, strychnine. This outcome and consequently their bitterness were mainly attributed to interactions with Glu265, Thr180 and/or Trp88 through the formation of direct hydrogen bonds. Therefore, the present results provide insights into the taste profiles of basil side-streams, leading to more sustainable and innovative uses of aromatic herbs residues. Full article

(This article belongs to the Special Issue Extraction and Characterization of Phenolic Compounds from Foods and Food Byproducts by Targeted and Untargeted LC-MS Methods)

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14 pages, 2939 KiB

Open AccessArticle

Photocatalytic Degradation of Ciprofloxacin: A Combined Experimental and Theoretical Study Using Curcumin and Hydrogen Peroxide

by Flórida L. P. de Paiva, Maria Vivian C. Silva, Ana Lara F. Mendonça, Cristiane S. Araújo, Lóide O. Sallum, Antonio S. N. de Aguiar, Alessandra R. Lima, Hamilton B. Napolitano, Mário J. F. Calvete and Lucas D. Dias

Separations 2024, 11(9), 260; https://doi.org/10.3390/separations11090260 - 2 Sep 2024

Viewed by 776

Abstract

Contamination of soil, water, and wastewater by pharmaceuticals, including antibiotics, is a global health problem. This work evaluated the use of a natural compound, curcumin (CUR), as a homogeneous photocatalyst, together with hydrogen peroxide (H₂O₂) as a benign oxidant, [...] Read more.

Contamination of soil, water, and wastewater by pharmaceuticals, including antibiotics, is a global health problem. This work evaluated the use of a natural compound, curcumin (CUR), as a homogeneous photocatalyst, together with hydrogen peroxide (H₂O₂) as a benign oxidant, to promote the photodegradation of ciprofloxacin (CIP). Furthermore, we carried out theoretical calculations using density functional theory (DFT) to assess the chemical reactivity of ciprofloxacin. In addition, the intermolecular interaction patterns of two crystalline polymorphs of the antibiotic drug were analyzed through Hirshfeld surfaces. Finally, calculations using the TD-DFT formalism were carried out to understand the effects on the CIP molecule caused by the simultaneous presence of the CUR molecule and ultraviolet-visible light (UV-Vis). A photooxidative effect was observed in the presence of the CUR photocatalyst (CIP + CUR (1:0.5)), resulting in a degradation of CIP of up to 24.4%. However, increasing the concentration of the CUR photocatalyst (ciprofloxacin + curcumin (1:1)) decreased the photodegradation of CIP, which may be caused by competition between the CIP molecule and CUR for ROS generated in situ. Additionally, the calculation results showed that the electronic excitations caused by the associated CIP + CUR structures affect the CIP molecule, resulting in the effects observed experimentally. The results show that CUR, when applied as a photosensitizing catalyst, presents synergistic potential with H₂O₂ in the photocatalytic degradation of ciprofloxacin. This photocatalytic process can be applied to the environmental remediation of pharmaceutical micropollutants, a subject of ongoing studies. Full article

(This article belongs to the Special Issue Light-Based Reactions for Water and Wastewater Treatment)

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14 pages, 3400 KiB

Open AccessArticle

Design of Selective Nanoparticles of Layered Double Hydroxide (Mg/Al-LDH) for the Analysis of Anti-Inflammatory Non-Steroidal Agents in Environmental Samples, Coupled with Solid-Phase Extraction and Capillary Electrophoresis

by David Aurelio-Soria, Xochitl H. Canales, Isai Vázquez-Garrido, Gabriela Islas, Giaan A. Álvarez-Romero and Israel S. Ibarra

Separations 2024, 11(9), 259; https://doi.org/10.3390/separations11090259 - 1 Sep 2024

Viewed by 665

Abstract

A simple, fast, and low-cost pre-concentration methodology based on the application of solid-phase extraction coupled to layered double hydroxides (LDHs) and capillary electrophoresis was developed for the determination of naproxen (NPX), diclofenac (DFC), and ibuprofen (IBP) in environmental sample waters. A systematic study [...] Read more.

A simple, fast, and low-cost pre-concentration methodology based on the application of solid-phase extraction coupled to layered double hydroxides (LDHs) and capillary electrophoresis was developed for the determination of naproxen (NPX), diclofenac (DFC), and ibuprofen (IBP) in environmental sample waters. A systematic study of the LDH composition was designed, including the effects of interlayer anions (NO₃⁻, Cl⁻, CO₃²⁻, BenO⁻, and SDS⁻) and the effect of molar ratio (Mg:Al). The optimal composition of MgAl/Cl⁻-LDH (Mg:Al; 1.5:1.0) was coupled to an SPE system: pH (neutral pH), LDH amount (15 mg), and extraction capacity ranged from 79.71 to 83.11% for the three anti-inflammatory non-steroidal agents analyzed. A recovery rate of up to 80.87% was obtained when 0.01 M chloride acid in methanol was used as the eluent and 50 mL of sample was used. Under optimal conditions, the linear range of the calibration curve ranges from 18.02 to 200 μg L⁻¹, with limits of detection ranging from 6.03 to 18.02 μg L⁻¹ for the three NSAIDs. The precision of the methodology was evaluated in terms of inter- and intra-day repeatability, with %RSD < 10% in all cases. The proposed method was applied to analyze environmental water samples (bottle, tap, cistern, well, and river water samples). The developed method is a robust technique capable of combining with other analytical methods to quantitatively determine anti-inflammatory non-steroidal agents. Full article

(This article belongs to the Special Issue Development of Materials for Separation and Analysis Applications)

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17 pages, 5134 KiB

Open AccessArticle

Applications of Sample Preparation Techniques in the Analysis of New Psychoactive Substances

by Lorna A. Nisbet, Fiona M. Wylie and Karen S. Scott

Separations 2024, 11(9), 258; https://doi.org/10.3390/separations11090258 - 30 Aug 2024

Viewed by 574

Abstract

The global rise of new psychoactive substances (NPSs) poses challenges for their analysis in biological matrices due to their complex chemistries and short market lifespan. A comparative study for the simultaneous extraction, separation, and detection of 19 NPSs was conducted. Six solid-phase extraction [...] Read more.

The global rise of new psychoactive substances (NPSs) poses challenges for their analysis in biological matrices due to their complex chemistries and short market lifespan. A comparative study for the simultaneous extraction, separation, and detection of 19 NPSs was conducted. Six solid-phase extraction (SPE) methods and one supported liquid extraction method (SLE) were compared for the extraction of analytes from blood, serum, plasma, and urine. Comparisons of four derivatization agents were conducted, at four temperatures and two incubation times. Extraction methods were assessed by precision, sensitivity, and extraction efficiency. Derivatizing agents were assessed on their selectivity and sensitivity, and a three-way ANOVA was conducted to determine statistical significance. CSDAU SPE cartridges were shown to be the most efficient when extracting analytes from blood, serum, and plasma, whereas Xcel I cartridges performed the strongest when extracting analytes from urine. SPE extraction efficiencies, when utilizing the best-performing cartridges, ranged from 49 to 119%. SLE successfully extracted all analytes from all matrices (ranging from 22 to 120%). Pentafluoropropionic anhydride: ethyl acetate was the most successful derivatizing agent, allowing all analytes to be detected, with the highest peak area responses and more unique spectra. The optimum temperature for incubation was 37 °C, with no statistical difference found between the two incubation times. Full article

(This article belongs to the Special Issue Forensic Toxicology: Biological Sampling and Development of Analytical Techniques)

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22 pages, 1699 KiB

Open AccessReview

Bioactive Compounds from Spirulina spp.—Nutritional Value, Extraction, and Application in Food Industry

by Blaženko Marjanović, Maja Benković, Tamara Jurina, Tea Sokač Cvetnić, Davor Valinger, Jasenka Gajdoš Kljusurić and Ana Jurinjak Tušek

Separations 2024, 11(9), 257; https://doi.org/10.3390/separations11090257 - 30 Aug 2024

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Abstract

The surging popularity of plant-based diets and the growing emphasis on clean-label products have intensified interest in Spirulina within the food industry. As more people adopt vegetarian, vegan, or flexitarian lifestyles, demand for plant-based protein sources has escalated. Spirulina’s high protein content [...] Read more.

The surging popularity of plant-based diets and the growing emphasis on clean-label products have intensified interest in Spirulina within the food industry. As more people adopt vegetarian, vegan, or flexitarian lifestyles, demand for plant-based protein sources has escalated. Spirulina’s high protein content and complete amino acid profile make it an ideal candidate to meet this demand. However, incorporating Spirulina into food products is not without its challenges. Its strong, earthy, or fishy taste can be off-putting to consumers and difficult to mask in food formulations. Furthermore, isolating Spirulina’s bioactive compounds while preserving their integrity is complex, especially considering the heat sensitivity of many of these components. Traditional extraction methods often employ high temperatures, which can degrade these valuable compounds. Consequently, there is a growing preference for non-thermal extraction techniques. This paper provides an overview of recent advancements in Spirulina cultivation, bioactive extraction, and their application in food products. Full article

(This article belongs to the Special Issue Extraction and Separation of Bioactive Molecules from Marine Flora and Fauna and By-Products of Aquatic Industries)

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17 pages, 4699 KiB

Open AccessArticle

Melt-Extruded High-Density Polyethylene/Pineapple Leaf Waste Fiber Composites for Plastic Product Applications

by Mandla Vincent Khumalo, Murugan Sethupathi, Sifiso John Skosana and Sudhakar Muniyasamy

Separations 2024, 11(9), 256; https://doi.org/10.3390/separations11090256 - 30 Aug 2024

Viewed by 945

Abstract

This study examines the impact of Pineapple Leaf Fiber (PALF) loading on the properties of High-Density Polyethylene (HDPE)/PALF composites successfully produced through a melt extrusion process. The melt-extruded HDPE/PALF composites were characterized by their thermal and mechanical properties and their morphologies. Subsequently, adding [...] Read more.

This study examines the impact of Pineapple Leaf Fiber (PALF) loading on the properties of High-Density Polyethylene (HDPE)/PALF composites successfully produced through a melt extrusion process. The melt-extruded HDPE/PALF composites were characterized by their thermal and mechanical properties and their morphologies. Subsequently, adding 5% maleic anhydride (MA) to the HDPE/PALF composite formulation led to significant improvements in the mechanical strength properties. Moreover, adding 10 wt.% PALF and 5% MA to the composites improves the crystallinity (10.38%) and Young’s modulus (17.30%) properties and affects the thermal stability. The optimal formulation is achieved with 10 wt.% PALF filler incorporated into the HDPE composite. This study highlights the promising potential of HDPE/PALF composites for plastic product applications. Full article

(This article belongs to the Section Materials in Separation Science)

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11 pages, 802 KiB

Open AccessArticle

Influence of Organic Carbon from Weathered Sediments on Triclocarban Distribution in Environmental Aqueous Systems

by Ion Ion, Raluca Madalina Senin and Alina Catrinel Ion

Separations 2024, 11(9), 255; https://doi.org/10.3390/separations11090255 - 25 Aug 2024

Viewed by 635

Abstract

In this study, the chemical distribution of triclocarban (TCC), in natural aqueous systems, between water and sediment, with different chemical compositions of the aqueous phase and different percentages of organic carbon (OC%) in the sediments is presented. The influences of the temperature, of [...] Read more.

In this study, the chemical distribution of triclocarban (TCC), in natural aqueous systems, between water and sediment, with different chemical compositions of the aqueous phase and different percentages of organic carbon (OC%) in the sediments is presented. The influences of the temperature, of the composition of the aqueous matrices of natural waters and (OC%) in the sediment over the solubility of triclocarban, and its distribution coefficient K_d values were studied. log K_D at 25 °C varied between 1.94 and 3.27 for a sediment with 5.50% OC and between 3.95 and 5.93% for a sediment with 6.75% OC, in the studied aqueous systems, with different concentrations of OC in the sediment. Full article

(This article belongs to the Special Issue Adsorption and Remediation of Emerging Pollutants from Water and Soil)

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12 pages, 1930 KiB

Open AccessArticle

Papaya Seed Extract and Recovery of Some Main Constituents

by Alessia Panusa, Francesca Romana Mammone, Paola Rotundo, Giuseppina Multari, Giovanna Palazzino and Francesca Romana Gallo

Separations 2024, 11(9), 254; https://doi.org/10.3390/separations11090254 - 23 Aug 2024

Viewed by 1035

Abstract

Carica papaya Linn. is one of the most common plants in almost all tropical countries. Its fruit is widely used as food or an ointment in traditional medicine. It is one of the few tropical fruits to contain glucotropaeolin (benzyl glucosinolate) detected in [...] Read more.

Carica papaya Linn. is one of the most common plants in almost all tropical countries. Its fruit is widely used as food or an ointment in traditional medicine. It is one of the few tropical fruits to contain glucotropaeolin (benzyl glucosinolate) detected in great quantity, mainly in the seeds of papaya. When cells in plant tissue are damaged, glucotropaeolin is hydrolysed by the enzyme myrosinase to benzyl isothiocyanate. The anticancer activity of this latter compound has been widely evidenced, but the metabolic profile of the papaya seed extracts is not reported in the literature. The objective of this study is to investigate the seed extracts of C. papaya L. by UHPLC-PDA ESI/MS, with and without the inactivation of myrosinase, and compare the recovery of some main components using two different inactivation procedures. The extracts (methanol/water, 60:40, v/v) were studied in negative and positive ionisation modes. Separations were carried out on an Acquity BEH C18 (50 × 2.1 mm i.d.) 1.7 μm analytical column, and 0.02% formic acid in water and acetonitrile was used as the mobile phase at a flow rate of 0.6 mL min⁻¹. Beyond the amino acids and glucotropaeolin already detected in papaya seeds, 4-hydroxybenzoic acid, which has never been detected in papaya seeds with this technique before, was identified. Moreover, mono-, di- and tri-glycosides of 4-hydroxybenzoic acid were putatively assigned. Glucotropaeolin, 4-hydroxybenzoic and tryptophan were quantified in seeds extracted after myrosinase deactivation. These three components were more effectively recovered using an oven than microwave myrosinase inactivation. Full article

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13 pages, 3593 KiB

Open AccessArticle

Application of Electrodialysis to Production of High-Purity Perrhenic Acid

by Patrycja Kowalik, Dorota Kopyto, Grzegorz Benke, Mateusz Ciszewski, Alicja Grzybek, Joanna Malarz, Karolina Pianowska, Karolina Goc, Szymon Orda, Dorota Babilas, Piotr Dydo and Katarzyna Leszczyńska-Sejda

Separations 2024, 11(9), 253; https://doi.org/10.3390/separations11090253 - 23 Aug 2024

Viewed by 691

Abstract

Laboratory tests were conducted for the production of high-purity perrhenic acid using a membrane technique—electrodialysis. Four solutions were used in the tests: diluate, concentrate, anolyte, and catholyte. The experiments were carried out in a two-stream system. The influence of basic process parameters, including [...] Read more.

Laboratory tests were conducted for the production of high-purity perrhenic acid using a membrane technique—electrodialysis. Four solutions were used in the tests: diluate, concentrate, anolyte, and catholyte. The experiments were carried out in a two-stream system. The influence of basic process parameters, including the flow rate of process streams or current density, on the purity of the obtained perrhenic acid were examined. Electrodialysis was also carried out as part of this research, aiming to concentrate the perrhenic acid >100 g/dm³. The concentrate solution obtained in the concentration tests, with a concentration of 148.7 g/dm³ HReO₄ and 530 mg/dm³ NH₄⁺, was then sent to the purification process using the electrodialysis method. The purification process was carried out until the concentration of NH₄⁺ ions was <100 mg/dm³ in the concentrate. Finally, perrhenic acid was obtained with the following composition: 169.7 g/dm³ HReO₄ and 70 mg/dm³ NH₄⁺. Based on this research, a technological scheme for producing high-purity HReO₄ by electrodialysis was developed. Full article

(This article belongs to the Special Issue Separation Technology for Metals Recovery)

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Separations, Volume 11, Issue 9 (September 2024) – 26 articles

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