Separations

16 pages, 2314 KiB

Open AccessArticle

Clarification of the Cardoon (Cynara cardunculus) Blanching Wastewater by Ultrafiltration—Study of Membrane Fouling and Flux Recovery after Chemical Cleaning

by Esperanza Maria Garcia-Castello, Monica Moratalla, Milagro Reig, Maria Isabel Iborra-Clar, Alicia Iborra-Clar and Antonio Diego Rodriguez-Lopez

Separations 2023, 10(7), 418; https://doi.org/10.3390/separations10070418 - 24 Jul 2023

Cited by 3 | Viewed by 1138

Abstract

This study focused on the clarification of real blanching wastewaters from the industrial processing of cardoon, a plant rich in polyphenols and belonging to the artichoke family (Cynara cardunculus). The aim of this study was to evaluate the performance of ultrafiltration [...] Read more.

This study focused on the clarification of real blanching wastewaters from the industrial processing of cardoon, a plant rich in polyphenols and belonging to the artichoke family (Cynara cardunculus). The aim of this study was to evaluate the performance of ultrafiltration (UF) as an initial clarification step prior to a subsequent nanofiltration treatment for the recovery and fractionation of polyphenols from these wastewaters. In this UF process, three commercial UF membranes with different pore sizes: 3 kDa, 15 kDa, and 50 kDa. The assessment of the clarification process was based on two key factors: permeate flux and the concentration of phenolic compounds. The membrane with a MWCO of 3 kDa was excluded as a potential UF membrane due to its limited performance in terms of permeate flux. The 15 kDa membrane showed comparable results in terms of cumulative flux to the 50 kDa membrane. However, further evaluation based on fouling index and water permeability recovery favored the 15 kDa membrane, indicating better performance. To gain insights into the flux decline mechanisms and understand membrane fouling, a study was conducted on the 15 kDa and 50 kDa membranes. The analysis revealed that the cake filtration model provided the best fit for both membranes. The study highlights the potential of UF membranes, specifically the 15 kDa membrane, for the clarification of cardoon blanching wastewater. Full article

(This article belongs to the Section Environmental Separations)

► Show Figures

Figure 1

11 pages, 1826 KiB

Open AccessArticle

Enantioselective Separation of Synthetic Cathinones by Capillary Electrophoresis with Ionic Liquid and Cyclodextrin Buffer Co-Additives

by Jennifer Buchanan Roberts and Christa L. Colyer

Separations 2023, 10(7), 417; https://doi.org/10.3390/separations10070417 - 24 Jul 2023

Viewed by 1256

Abstract

The enantioselective separation of synthetic cathinones via capillary electrophoresis with ultraviolet detection (CE-UV) was successfully achieved using an acidic formate buffer with the ionic liquid tetrabutylammonium chloride (TBAC) and beta-cyclodextrin (β-CD) as co-additives. Synthetic cathinones (also known as “bath salts”) belong to a [...] Read more.

The enantioselective separation of synthetic cathinones via capillary electrophoresis with ultraviolet detection (CE-UV) was successfully achieved using an acidic formate buffer with the ionic liquid tetrabutylammonium chloride (TBAC) and beta-cyclodextrin (β-CD) as co-additives. Synthetic cathinones (also known as “bath salts”) belong to a class of unregulated drugs labeled new psychoactive substances (NPS). These drugs are readily available and can cause paranoia, confusion, violence, and suicidal thoughts. The stereochemistry of synthetic cathinones, as with other drugs, can influence their potency, toxicity, metabolism, and interaction with other molecules. Thus, it is important to be able to effectively separate different types of synthetic cathinone as well as to resolve enantiomers of each. A study of buffer additives, pH, and counter ions was conducted to identify a system yielding complete enantioselective separation of synthetic cathinones by capillary electrophoresis. Buffer additives TBAC and β-CD, when used separately, did not afford the desired separation; however, when employed as co-additives, enantiomers of each of six different bath salt standards (pentylone, 4-MEC, methylone, MDPBP, MDPV, and naphyrone) were resolved. Achieving this separation of a complex mixture of closely related illicit drugs by CE using an ionic liquid and cyclodextrin together, as buffer co-additives, may provide a new starting point from which to approach the enantiomeric analysis of other drug samples as syntheses of NPS continue to rapidly evolve to evade regulation and law enforcement. Full article

(This article belongs to the Special Issue Feature Papers in Separations from Editorial Board Members)

► Show Figures

Graphical abstract

15 pages, 2178 KiB

Open AccessArticle

Preconcentration of Volatile Organic Compounds on Carbon Magnetic Sorbents in the Analysis of Air by Using the Configuration Change of the Sorbent Bed during the Transition from Sorption to Thermodesorption GC-FID

by Oleg Rodinkov, Victor Postnov, Valery Spivakovskyi, Ekaterina Znamenskaya, Anastasia Zheludovskaya and Pavel Nesterenko

Separations 2023, 10(7), 416; https://doi.org/10.3390/separations10070416 - 23 Jul 2023

Cited by 3 | Viewed by 1285

Abstract

The new scheme of the rapid preconcentration of volatile organic substances followed by the thermodesorption and gas chromatographic determination by using a flame ionization detector is proposed for the analysis of air. The scheme implies a change in the geometry of the adsorbent [...] Read more.

The new scheme of the rapid preconcentration of volatile organic substances followed by the thermodesorption and gas chromatographic determination by using a flame ionization detector is proposed for the analysis of air. The scheme implies a change in the geometry of the adsorbent layer in a column during the transition from adsorption to thermal desorption steps. The extraction of analytes is carried out in a wide tube, allowing quantitative adsorption at higher flow rates of the analyzed air passed through the magnetic sorbent held in a thin layer retained by a permanent magnet without any supporting frits. Novel magnetic adsorbents composed of magnetite or a zirconia/magnetite core and pyrocarbon shell are developed for this application. At the end of the adsorption step, the magnet moved out of the system, and the adsorbent transferred under the gravity force into a narrow tube, which provides the more efficient heating of the adsorbent and minimal blurring of the analyte zones during the subsequent thermal desorption. The proposed scheme allows a significant reduction (approximately 10 times) of the time required for the preconcentration of analytes, which is illustrated by the GC determination of alcohols (butanol-1, pentanol-1), phenol, and o-cresol in the air. Full article

(This article belongs to the Collection Feature Paper Collection in Section 'Materials in Separation Science')

► Show Figures

Graphical abstract

19 pages, 3996 KiB

Open AccessArticle

Air-Purge Regenerative Direct Air Capture Using an Externally Heated and Cooled Temperature-Swing Adsorber Packed with Solid Amine

by Heak Vannak, Yugo Osaka, Takuya Tsujiguchi and Akio Kodama

Separations 2023, 10(7), 415; https://doi.org/10.3390/separations10070415 - 21 Jul 2023

Cited by 2 | Viewed by 2281

Abstract

CO₂ capture from air is crucial in achieving negative emissions. Based on conventional or newly developed high-enriching processes, we investigated the rough enrichment of CO₂ from air via an externally heated or cooled adsorber (temperature-swing adsorption, TSA), along with air purge [...] Read more.

CO₂ capture from air is crucial in achieving negative emissions. Based on conventional or newly developed high-enriching processes, we investigated the rough enrichment of CO₂ from air via an externally heated or cooled adsorber (temperature-swing adsorption, TSA), along with air purge using double-pipe heat exchangers packed with low-volatility polyamine-loaded silica. A simple adsorption–desorption cycle was attempted in a TSA experiment, by varying the temperature from 20 °C to 60 °C using moist air, yielding an average CO₂ concentration of product gas that was ~17 times higher than the feed air, but the CO₂ recovery rate was poor. A double-step adsorption process was applied to increase CO₂ adsorption and recovery simultaneously. In this process, substantial-CO₂-concentration gas was used as the product gas, and the remaining gas was used as the reflux feed gas for adsorber. This method can provide a product gas with ~100 times higher CO₂ concentration than raw gas, with a recovery ratio ~60% under the shortest adsorption/desorption time and the longest refluxing time of cycle operation. Therefore, the refluxing step significantly helped to enhance CO₂ capture via adsorption from elevated-CO₂-concentration recirculating gas. With this CO₂ concentration, the product gas can serve as the CO₂ supplement for the growing plant processes. Full article

(This article belongs to the Topic Carbon Capture Science & Technology (CCST))

► Show Figures

Figure 1

2 pages, 172 KiB

Open AccessEditorial

Harnessing Buffer Solutions to Modify the Association State of Ferritin Nanoparticles

by Alessio Incocciati, Chiara Cappelletti, Alberto Boffi, Alberto Macone and Alessandra Bonamore

Separations 2023, 10(7), 414; https://doi.org/10.3390/separations10070414 - 20 Jul 2023

Viewed by 1052

Abstract

Recent years have witnessed remarkable progress in the field of drug delivery driven by the pursuit of efficient and targeted delivery systems [...] Full article

(This article belongs to the Section Purification Technology)

15 pages, 1797 KiB

Open AccessArticle

Diagnostic Strategies for Brain Doping in an Animal Model via Quantitative Analysis of Neurochemicals

by Yoeseph Cho, Seongeun Jeon, Yejin Lee, Hana Park, Yinglan Xu, Mijin Jeon, Sunmi Jung, Minyoung Kim, Ahlim Chin, Sang Sun Yoon and Junghyun Son

Separations 2023, 10(7), 413; https://doi.org/10.3390/separations10070413 - 19 Jul 2023

Viewed by 1513

Abstract

Brain doping is a novel form of doping that involves stimulating specific brain regions to enhance sports performance. However, to the best of our knowledge, there is currently no established provision or detection method for it. As brain stimulation ultimately induces alterations in [...] Read more.

Brain doping is a novel form of doping that involves stimulating specific brain regions to enhance sports performance. However, to the best of our knowledge, there is currently no established provision or detection method for it. As brain stimulation ultimately induces alterations in neurochemical concentrations, this study aimed to develop a diagnostic strategy for brain doping. We successfully developed and validated a sensitive simultaneous analysis method for 23 neurochemicals present in urine. Simple derivatization was employed to overcome ionization efficiency, enabling the effective detection of all the target compounds within 5 min. Additionally, we developed an animal model system using rats to replicate brain-doping scenarios and establish a diagnostic strategy. Behavior tests confirmed improved sports performance in the brain stimulation group. By examining changes in the distribution patterns of the target substances in urine samples, we observed that neurochemicals could be used as potential biomarkers for brain-doping diagnosis. The developed method allows the effective simultaneous analysis of multiple neurochemicals in biological samples and is expected to have various applications, including doping control. Thus, changes in the distribution pattern of neurochemicals could serve as a basis for brain-doping diagnosis. Full article

(This article belongs to the Section Bioanalysis/Clinical Analysis)

► Show Figures

Figure 1

12 pages, 1231 KiB

Open AccessArticle

Complex Evaluation of Storage Impact on Maize (Zea mays L.) Quality Using Chromatographic Methods

by Calin Topan, Mihai Nicolescu, Dorina Simedru and Anca Becze

Separations 2023, 10(7), 412; https://doi.org/10.3390/separations10070412 - 18 Jul 2023

Cited by 1 | Viewed by 2409

Abstract

Maize (Zea mays L.), a food crop cultivated worldwide, is renowned for its nutritional and economic value. However, its quality can be significantly affected by various storage conditions, leading to changes in its nutritional composition and potential contamination with harmful substances, such [...] Read more.

Maize (Zea mays L.), a food crop cultivated worldwide, is renowned for its nutritional and economic value. However, its quality can be significantly affected by various storage conditions, leading to changes in its nutritional composition and potential contamination with harmful substances, such as aflatoxins. This article presents a comprehensive evaluation of the impact of storage on maize quality, focusing on several key parameters analyzed using liquid chromatographic methods and FT-NIR spectrometry. The research reveals a decline in the concentrations of key nutrients over the storage period. Specifically, there was a 19.7% loss in vitamin B1, a 12.43% loss in vitamin B3, a 16.96% loss in α-tocopherol, a 13.61% loss in total tocopherols, and an 8.02% loss in β-carotene. Aflatoxins were mostly undetectable, with one exception in January that remained below the maximum permitted level of 0.3 µg/kg. The parameters include the concentration of vitamins B1, B3, α-tocopherol, total tocopherols, β-carotene, aflatoxin B1, total aflatoxins, carbohydrate content, and protein content. Aflatoxins were mostly undetectable, with one exception in January—0.3 µg/kg—that remained below the maximum permitted level. The study underscores the importance of cooling maize immediately after drying to minimize nutrient loss, providing valuable insights for optimizing storage processes to maintain the nutritional quality of maize. Full article

(This article belongs to the Special Issue Extraction and Analytical Methods in Food Technology)

► Show Figures

Figure 1

12 pages, 680 KiB

Open AccessArticle

Validation of the Ultra-Performance Liquid Chromatography with Tandem Mass Spectrometry Method for Simultaneous Analysis of Eighteen Compounds in the Traditional Herbal Prescription, Sanjoin-Tang

by Chang-Seob Seo and Hyeun-Kyoo Shin

Separations 2023, 10(7), 411; https://doi.org/10.3390/separations10070411 - 18 Jul 2023

Cited by 1 | Viewed by 1064

Abstract

Sanjoin-tang (SJIT) is an ancient oriental medicine prescription listed in the Jinguiyaolue that is mainly used for the treatment of primary insomnia. This study was conducted to develop and validate an ultra-performance liquid chromatography with tandem mass spectrometry (UPLC–MS/MS) simultaneous analysis method for [...] Read more.

Sanjoin-tang (SJIT) is an ancient oriental medicine prescription listed in the Jinguiyaolue that is mainly used for the treatment of primary insomnia. This study was conducted to develop and validate an ultra-performance liquid chromatography with tandem mass spectrometry (UPLC–MS/MS) simultaneous analysis method for the quality control of SJIT using 18 target compounds. The 18 analytes were separated on an Acquity UPLC BEH C₁₈ column maintained at 45 °C using a mobile phase composed of distilled water and acetonitrile. The MS system was used to simultaneously detect all analytes using the multiple reaction monitoring (MRM) method of Xevo TQ-XS coupled with an electrospray ionization source. The concentrations of the 18 analytes investigated in the SJIT samples ranged from below the limit of detection to 9.553 mg/g. In conclusion, the validated UPLC–MS/MS MRM analysis method can be used to obtain basic data to establish chemical-nonclinical linkage efficacy and for the clinical research and quality evaluation of SJIT. Full article

(This article belongs to the Topic Application of Liquid Chromatography-Mass Spectrometry and Related Techniques)

► Show Figures

Figure 1

21 pages, 13274 KiB

Open AccessArticle

Variation of Flow Hydrodynamic Parameters and Prediction of Particle Separation Indices in the Spiral Concentrator with the Regulation of Pitch-Diameter Ratio

by Shuling Gao, Xiaohong Zhou, Lingguo Meng, Qiang Zhao and Wengang Liu

Separations 2023, 10(7), 410; https://doi.org/10.3390/separations10070410 - 17 Jul 2023

Viewed by 1204

Abstract

The pitch-diameter ratio is an important design indicator affecting the separation performance of spirals. Based on the numerical simulation method, this paper systematically investigated the variation of flow hydrodynamic parameters in the spiral concentrator with the regulation of the pitch-diameter ratio. The radial [...] Read more.

The pitch-diameter ratio is an important design indicator affecting the separation performance of spirals. Based on the numerical simulation method, this paper systematically investigated the variation of flow hydrodynamic parameters in the spiral concentrator with the regulation of the pitch-diameter ratio. The radial distribution and variation trend of hematite and quartz particles with different particle sizes are further analyzed. Additionally, the separation indices of hematite and quartz with different particle size combinations were predicted. The results show that the tangential velocity, maximum radial velocity, velocity shear rate, and Reynolds number of fluid in each region decrease with the increase of the pitch-diameter ratio. The range of laminar flow gradually expands as the pitch-diameter ratio increases. There are significant differences in depth of water, ratio of inward and outward flows, and secondary flow velocity in different regions. Some flow hydrodynamic parameters at the inner trough reach relative equilibrium at a pitch-diameter ratio of 0.675. Hematite and quartz particles form a selective distribution in the trough surface, which comprehensively reflects the density effect, particle size effect, following flow effect of fine particles, and the effect of interstitial trickling of high-density fine particles. Fine hematite and coarse quartz form a large amount of misplaced material, and there is a corresponding mixing area. With the increase in pitch-diameter ratio, coarse and fine hematite particles migrate inward and outward, respectively. With the increase in pitch-diameter ratio, the misplaced amount of quartz on the inner trough decreases, but the outward migration distance of coarse quartz is smaller. Increasing the pitch-diameter ratio is beneficial to the separation of combined feedings of coarse hematite and quartz but unfavorable to that of fine hematite and quartz. The maximum separation efficiency of coarse hematite and fine quartz can reach 85.74%, and the iron grade of the inner product can reach 65.96% when the pitch-diameter ratio is 0.675 and the splitter location is 115 mm. The changing trend of separation indices in this feeding is closely related to the variation of fluid parameters and the change in the radial distribution of single mineral particles. The research results can provide references for the structural design of spirals, the selection of feed particle size, and the adjustment of splitter location. Full article

(This article belongs to the Section Analysis of Energies)

► Show Figures

Figure 1

17 pages, 1644 KiB

Open AccessArticle

A One-Step Sample Processing Method in Combination with HPLC-MS/MS for the Simultaneous Quantification of Atorvastatin, Ezetimibe and Three Metabolites including o-Hydroxyl Atorvastatin, p-Hydroxyl Atorvastatin, and Ezetimibe-Glucuronide in Human Plasma

by T. Nguyen Nguyen Le, Nai Ngoc Chuong and Tuan Duc Nguyen

Separations 2023, 10(7), 409; https://doi.org/10.3390/separations10070409 - 17 Jul 2023

Cited by 1 | Viewed by 1837

Abstract

A simple and sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method has been developed for the simultaneous determination of atorvastatin (ATOR), ezetimibe (EZM), and their three metabolites, including o-hydroxyl atorvastatin (o-OH ATOR), p-hydroxyl atorvastatin (p-OH ATOR), and ezetimibe–glucuronide [...] Read more.

A simple and sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method has been developed for the simultaneous determination of atorvastatin (ATOR), ezetimibe (EZM), and their three metabolites, including o-hydroxyl atorvastatin (o-OH ATOR), p-hydroxyl atorvastatin (p-OH ATOR), and ezetimibe–glucuronide (EZM-G) in human plasma using benzyl paraben (BP) as the internal standard (IS). The analytes and IS were ionized using ESI positive ion mode (ATOR, o-OH ATOR, and p-OH ATOR), ESI negative ion mode (EZM, EZM-G, and BP), and operated in multiple reaction monitoring (MRM) mode. They were then extracted via salting-out assisted liquid–liquid extraction with acetonitrile and analyzed via liquid chromatography on a reversed-phase chromatographic column (50 mm × 4.6 mm; 3.5 µm) using a mixture of acetonitrile and an acetic acid solution (0.5%) as the mobile phase, showing high extraction efficiency (>70%), and a minimized matrix effect. The method was satisfactorily validated, and it showed excellent linearity over wide concentration ranges of 0.06–15 ng/mL, 0.6–150 ng/mL, 0.4–100 ng/mL, 0.12–30 ng/mL, and 0.05–3 ng/mL for EZM, EZM-G, ATOR, o-OH ATOR, and p-OH ATOR, respectively. Full article

(This article belongs to the Topic Application of Analytical Chemistry in Exercise Physiology and Pharmacology)

► Show Figures

Graphical abstract

21 pages, 1888 KiB

Open AccessReview

Review of Photochemical Activity of Dissolved Black Carbon in Aquatic Environments: Primary Influencing Factors and Mechanisms

by Huaying Liu, Yina Tu, Wei Tang, Weilin Wu and Yingjie Li

Separations 2023, 10(7), 408; https://doi.org/10.3390/separations10070408 - 16 Jul 2023

Cited by 1 | Viewed by 1726

Abstract

Dissolved black carbon (DBC), the particular component of black carbon that can be dissolved in the water, which accounts for ~10% of the organic carbon cycle in the earth’s water body, is an essential member of the dissolved organic matter (DOM) pool. In [...] Read more.

Dissolved black carbon (DBC), the particular component of black carbon that can be dissolved in the water, which accounts for ~10% of the organic carbon cycle in the earth’s water body, is an essential member of the dissolved organic matter (DOM) pool. In contrast to DOM, DBC has a higher proportion of conjugated benzene rings, which can more efficiently encourage the degradation of organic micropollutants in the aquatic environment or more rapidly generate reactive oxygen species to photodegrade the organic micropollutants. Therefore, it is of great significance to study the changes and mechanisms of DBC photochemical activity affected by different factors in the water environment. Our work reviewed the main influencing factors and mechanisms of the photochemical activity of DBC. It focuses on the methodologies for the quantitative and qualitative investigation of the photochemical activity of DBC, the impact of the biomass source, the pyrolysis temperature of biochar, and the primary water environmental parameters on the photochemical activity of DBC and the indirect photodegradation of pollutants. Based on this, a potential future study of DBC photochemical activity has been prospected. Full article

(This article belongs to the Section Environmental Separations)

► Show Figures

Figure 1

14 pages, 2350 KiB

Open AccessArticle

New Processes to Extract and Purify Phosvitin by Using Aqueous Salt Solutions, Precipitation and Ultrafiltration Techniques

by Ismael Marcet, Florencia Ridella, Mario Díaz and Manuel Rendueles

Separations 2023, 10(7), 407; https://doi.org/10.3390/separations10070407 - 14 Jul 2023

Cited by 1 | Viewed by 1439

Abstract

Phosvitin is the most phosphorylated naturally occurring protein and it is concentrated in the granular fraction of egg yolk. It has interesting antioxidant and cation chelating properties that can be used to preserve food and cosmetics, but its industrial application is limited as [...] Read more.

Phosvitin is the most phosphorylated naturally occurring protein and it is concentrated in the granular fraction of egg yolk. It has interesting antioxidant and cation chelating properties that can be used to preserve food and cosmetics, but its industrial application is limited as its separation relies on the use of organic solvents and chromatographic techniques, which are expensive and difficult to assimilate in a continuous procedure. In this study, we propose a new phosvitin separation process using substances legally accepted for use in the food industry (NaCl and HCl), employing egg yolk granules as raw material. In this case, the NaCl concentration and the pH of the solution of granules were screened in order to obtain a phosvitin-rich supernatant after centrifugation. Additionally, two new processes were proposed to purify this phosvitin-rich solution. The first was the precipitation of impurities during the desalting stage at optimized pH values. The second was ultrafiltration under selected pH value conditions. A low nitrogen/phosphorous (N/P) atomic ratio is considered a quality parameter, with 3.6 ± 0.2 being the value of the phosvitin-rich supernatant. The two purification processes provided highly purified phosvitin with a similar N/P value of 2.5 ± 0.1. The high level of purification of the phosvitin was confirmed using electrophoresis and ion-exchange chromatography. In particular, the purified phosvitin obtained via ultrafiltration is already desalted and membrane technology is more easily scalable than that based on chromatography, thus facilitating the industrial separation and commercialization of the phosvitin. Full article

(This article belongs to the Special Issue Isolation, Elucidation and Synthesis of Bioactive Natural Products)

► Show Figures

Figure 1

11 pages, 1854 KiB

Open AccessArticle

Rapid and Simultaneous Extraction of Bisabolol and Flavonoids from Gymnosperma glutinosum and Their Potential Use as Cosmetic Ingredients

by Mayra Beatriz Gómez-Patiño, Juan Pablo Leyva Pérez, Marcia Marisol Alcibar Muñoz, Israel Arzate-Vázquez and Daniel Arrieta-Baez

Separations 2023, 10(7), 406; https://doi.org/10.3390/separations10070406 - 14 Jul 2023

Cited by 2 | Viewed by 1705

Abstract

Gymnosperma glutinosum is a plant popularly known as “popote”, “tatalencho”, “tezozotla” or “pegajosa”, and it is used in traditional medicine in the region of Tehuacán, Puebla (Mexico), for the treatment of jiotes and acne and to cure diarrhea using the aerial parts in [...] Read more.

Gymnosperma glutinosum is a plant popularly known as “popote”, “tatalencho”, “tezozotla” or “pegajosa”, and it is used in traditional medicine in the region of Tehuacán, Puebla (Mexico), for the treatment of jiotes and acne and to cure diarrhea using the aerial parts in infusions. To analyze the phytochemical composition, we have developed a rapid protocol for the extraction and separation of the components of the aerial parts of G. glutinosum. After a maceration process, chloroformic and methanolic extracts were obtained and analyzed. Extracts were evaluated by GC-MS (gas chromatography-mass spectrometry), and their composition revealed the presence of (−)-α-bisabolol (BIS) as the main component in the chloroformic extract, which was isolated and analyzed by ¹H NMR to confirm its presence in the plant. The analysis of methanolic extracts by UPLC-MS (ultra-performance liquid chromatography-mass spectrometry) revealed the occurrence of six methoxylated flavones with m/z 405.08 (C₁₉H₁₈O₁₀), m/z 419.09 (C₂₀H₂₀O₁₀) and m/z 433.11 (C₂₁H₂₂O₁₀), and a group of C20-, C18-hydroxy-fatty acids, which give the plant its sticky characteristic. The presence of BIS, an important sesquiterpene with therapeutic skin effects, as well as some antioxidant compounds such as methoxylated flavones and their oils, could play an important role in cosmetology and dermatology formulations. Full article

(This article belongs to the Special Issue Analysis of Natural Bioactive Compounds in Plant, Food, and Pharmaceutical Products Using Chromatographic Techniques)

► Show Figures

Graphical abstract

15 pages, 16586 KiB

Open AccessArticle

Fluorinated Poly(ionic liquid)s Coated Superhydrophobic Functional Materials with Efficient Oil/Water Separation Performance

by Fumin Shen, Xuna Cheng, Shunyang Yao and Yuanchao Pei

Separations 2023, 10(7), 405; https://doi.org/10.3390/separations10070405 - 14 Jul 2023

Cited by 2 | Viewed by 1424

Abstract

There is an urgent need to develop new and improved oil-water separation materials with high stability and reusability for the cleanup of oily environmental pollutants. Here, fluorinated poly(ionic liquid)s were synthesized and their structure and property were characterized by nuclear magnetic resonance spectroscopy, [...] Read more.

There is an urgent need to develop new and improved oil-water separation materials with high stability and reusability for the cleanup of oily environmental pollutants. Here, fluorinated poly(ionic liquid)s were synthesized and their structure and property were characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. These fluorinated poly(ionic liquid)s were proposed as superhydrophobic coating on different metallic substrates through the combination of tethering fluorine groups in the PIL’s cation and anion exchange, and the superhydrophobic coating showed compactly stacked morphology under scanning electron microscope. The results of surface wettability experiments indicated that nearly all the fabricated materials showed a water contact angle larger than 150°, which is devoted to superhydrophobic nature. Moreover, for longer alkyl chain ILs and materials with smaller pore sizes, the water contact angle can be increased. At the same time, the fabricated superhydrophobic material exhibits a relatively high oil phase permeate flux, benefiting from the loose fibrous structure. Take the PIL@SSM300 for instance, the permeate fluxes were reached as high as 374,370 L·m⁻²·h⁻¹, 337,200 L·m⁻²·h⁻¹ and 302,013 L·m⁻²·h⁻¹ for petroleum ether, hexane and cyclohexane, respectively. Instead, water is effectively repelled from the superhydrophobic surface. These virtues make the fabricated superhydrophobic material an effective membrane for oil/water separation under gravity. The separation efficiency and water contact angle are nearly unaffected after at least 20 cycles, confirming the excellent robustness of the coatings. These efficient poly(ionic liquid)s-based superhydrophobic materials possessed the potential to be used for oil/water separation. Full article

(This article belongs to the Special Issue Application of Ionic Liquids in Separation Science)

► Show Figures

Figure 1

12 pages, 2109 KiB

Open AccessArticle

Design Strategy for Performance Enhancement of Vertical Plate Microdistillators

by Yosuke Muranaka, Taisuke Maki, Kosuke Nishigaya and Kazuhiro Mae

Separations 2023, 10(7), 404; https://doi.org/10.3390/separations10070404 - 14 Jul 2023

Cited by 1 | Viewed by 1173

Abstract

Microdevices have been actively implemented in chemical processes, such as in mixing and reactions. However, microseparation devices, excluding extraction devices, are still under development. In distillation, the use of microdevices has been expected to improve separation performance, as their large specific surface area [...] Read more.

Microdevices have been actively implemented in chemical processes, such as in mixing and reactions. However, microseparation devices, excluding extraction devices, are still under development. In distillation, the use of microdevices has been expected to improve separation performance, as their large specific surface area enables a rapid vapor–liquid equilibrium and for large temperature gradients to be easily realized. In this study, improvements in throughput and product purities in microdistillation devices were achieved for ethyl acetate–toluene distillation. At low feedstock flow rates, ethyl acetate was successfully purified to 99.5 wt%. Although the performance decreased with increasing feedstock flow rate, by increasing the channel length, this performance decrease was suppressed even at high flow rates. The thickness of the channel was also important, and the highest performance was observed at the lowest thickness of 0.5 mm. A performance evaluation using the HETP showed that the efficiency was seven times higher than that of conventional packed column distillators. Full article

(This article belongs to the Topic Advances in Chemistry and Chemical Engineering)

► Show Figures

Graphical abstract

14 pages, 3960 KiB

Open AccessArticle

Stripping Enhanced Distillation—A Novel Application in Renewable CO₂ to Dimethyl Ether Production and Purification

by Vladimir Dikić, Lawien Zubeir, Marija Sarić and Jurriaan Boon

Separations 2023, 10(7), 403; https://doi.org/10.3390/separations10070403 - 13 Jul 2023

Cited by 2 | Viewed by 2442

Abstract

The transition towards a CO₂ neutral industry is currently spurring many new developments regarding processes for the conversion of CO₂, or CO₂-rich streams, into platform molecules such as methanol and dimethyl ether (DME). New processes give rise to [...] Read more.

The transition towards a CO₂ neutral industry is currently spurring many new developments regarding processes for the conversion of CO₂, or CO₂-rich streams, into platform molecules such as methanol and dimethyl ether (DME). New processes give rise to new separation challenges, as well as novel opportunities for joint optimization of reaction and separation. In this context, the separation of CO₂ and DME can be performed very efficiently using the newly developed concept of stripping enhanced distillation (SED). SED is a distillation process that utilizes an additional stripping component (clearing gas) to promote the separation in the column. SED benefits from the utilization of the feedstock components as a clearing gas that can afterwards be recycled back to the conversion unit with the vapor distillate. Strongly improving the separation performance in the column, this approach also removes the need for external stripping mediums and, in addition, this recycling approach may significantly reduce the demand on the conversion unit upstream of SED. The benefits of using SED are demonstrated for two different processes for DME synthesis: (i) CO₂–DME separation after the sorption enhanced DME synthesis (SEDMES) process, using hydrogen as clearing gas, and (ii) CO₂–DME separation after direct DME synthesis via dry reforming (DIDR), using methane as a clearing gas. For the different cases, it is shown that, with minimal adaptations, the energy consumption for distillation is reduced by 20–30%, while product losses are minimized at the same time. Full article

(This article belongs to the Special Issue Advances in Separation Engineering)

► Show Figures

Graphical abstract

14 pages, 1610 KiB

Open AccessArticle

A Comparison of Quantitative Composition and Bioactivity of Oils Derived from Seven North American Varieties of Hops (Humulus lupulus L.)

by Ágnes M. Móricz, Mariola Bartoszek, Justyna Polak, Patrycja Marczewska, Magdalena Knaś, Andrea Böszörményi, József Fodor, Teresa Kowalska and Mieczysław Sajewicz

Separations 2023, 10(7), 402; https://doi.org/10.3390/separations10070402 - 12 Jul 2023

Cited by 3 | Viewed by 1659

Abstract

Seven commercial hop (Humulus lupulus L.) oils originating from a selection of North American hop varieties (Amarillo, Azacca, Cascade, Centennial, Chinook, Saaz, and Ahhhroma) and six homemade hop oils hydrodistilled from the same commercial hop pellets (except Ahhhroma) were compared. Seven terpenes [...] Read more.

Seven commercial hop (Humulus lupulus L.) oils originating from a selection of North American hop varieties (Amarillo, Azacca, Cascade, Centennial, Chinook, Saaz, and Ahhhroma) and six homemade hop oils hydrodistilled from the same commercial hop pellets (except Ahhhroma) were compared. Seven terpenes regarded as hop oil markers (i.e., α-pinene, β-pinene, β-myrcene, β-ocimene, limonene, β-caryophyllene, and α-humulene) and methyl heptanoate were identified and quantified by GC–MS and GC-FID. The antioxidant potential of the commercial hop oil samples was evaluated using electron paramagnetic resonance (EPR) spectroscopy, while their components’ antibacterial (against Aliivibrio fischeri) and enzyme (α-glucosidase and lipase) inhibition activities were screened using high-performance thin-layer chromatography (HPTLC)-based assays. A distinct feature of five of the commercial hop oils (except Saaz and Ahhhroma) was relatively high contents of β-myrcene (between 4.21 and 6.40 µg mg⁻¹ hop oil). Azacca, Cascade, and Centennial hydrodistilled oils had perceptibly higher contents of β-caryophyllene than the rest, and most of them (except Chinook) contained relatively high amounts of α-humulene. Differences between the terpene profiles of the commercial and homemade hydrodistilled hop oils suggested that the commercial hop oils were derived from hop cones in a process different from hydrodistillation. The oils showed relatively low antioxidant potential, comparable to that of popular beers and white wines. The highest antioxidant potential was observed in Ahhhroma oil, while it was very low in Centennial oil, and no antioxidant potential was observed in Cascade and Saaz oils. The developed streamlined workflow, including parallel HPTLC-directed bioassays and HPTLC—TLC–MS Interface—SPME–GC–MS, enabled the identification of β-myrcene, dimyrcenes, β-farnesene, and 2-methylbutyl isobutyrate as anti-obesity compounds and β-farnesene, β-myrcene, and 2-methylbutyl isobutyrate as weak antibacterial hop oil components. Full article

► Show Figures

Graphical abstract

16 pages, 4185 KiB

Open AccessFeature PaperArticle

Removal of Indium Ions from Aqueous Solutions Using Hydroxyapatite and Its Two Modifications

by Inga Zinicovscaia, Nikita Yushin, Doina Humelnicu, Maria Ignat, Ionel Humelnicu, Dmitrii Grozdov and Tatyana Vershinina

Separations 2023, 10(7), 401; https://doi.org/10.3390/separations10070401 - 12 Jul 2023

Cited by 3 | Viewed by 1585

Abstract

Hydroxyapatite (HAP) coupled with its two modifications HAP P123 and HAP F127 were applied for indium removal from aqueous solutions. Adsorbents’ abilities to remove indium ions were assessed in relation to pH, time of contact, indium concentration, temperature, and presence of co-existing ions. [...] Read more.

Hydroxyapatite (HAP) coupled with its two modifications HAP P123 and HAP F127 were applied for indium removal from aqueous solutions. Adsorbents’ abilities to remove indium ions were assessed in relation to pH, time of contact, indium concentration, temperature, and presence of co-existing ions. Adsorption was discovered to be pH-dependent for all sorbents, with maximum indium ion removal at pH 4.0. Both the Langmuir and the Freundlich isotherm models were used to explain the experimental results. For all adsorbents, the Freundlich isotherm provided a better description of the equilibrium of the sorption. The sorption capacity computed from the Langmuir model changed from 10,799 mg/g for HAP F127 to 11071 mg/g for HAP. A number of models were used to describe the adsorption’s kinetics. The adsorption of indium on HAP was better described by the pseudo-second-order model, on HAP P123 by the pseudo-first-order model, and on HAP F127 by the Elovich model. Thermodynamic parameters showed that indium ions’ adsorption onto HAP adsorbents was a feasible, spontaneous, and exothermic process. The effectiveness of indium removal by the examined adsorbents was unaffected by the presence of other metal ions in the solutions. ORCA quantum chemistry software was used to theoretically examine the interactions between the surfaces of adsorbents and the indium ions. High desorption efficiency showed that the applied adsorbents can be used for manifold wastewater treatment. Full article

(This article belongs to the Special Issue Applications of Porous Materials in Adsorption)

► Show Figures

Figure 1

13 pages, 2568 KiB

Open AccessArticle

Basic Research on Selective Extraction of Iron from Titanium Dioxide Waste Acid to Prepare Iron Phosphate Precursors

by Xuejiao Cao, Yang Chen, Xinxing Liang, Yibing Li, Weiguang Zhang, Zhenlei Cai and Ting’an Zhang

Separations 2023, 10(7), 400; https://doi.org/10.3390/separations10070400 - 11 Jul 2023

Cited by 2 | Viewed by 1868

Abstract

In view of the current situation wherein acid resources and valuable components in titanium dioxide waste acid cannot be effectively extracted and are prone to secondary pollution, our research team proposed a new technique consisting of step extraction and the comprehensive utilization of [...] Read more.

In view of the current situation wherein acid resources and valuable components in titanium dioxide waste acid cannot be effectively extracted and are prone to secondary pollution, our research team proposed a new technique consisting of step extraction and the comprehensive utilization of titanium dioxide waste acid. In this paper, the thermodynamics of selective precipitation and the preparation of doped iron phosphate from waste acid were studied. The thermodynamics results show that the content of Al³⁺, Mn²⁺, Mg²⁺, and Ca²⁺ in the reaction system can be tuned by adjusting the pH during the pre-precipitation process. In the first step, these impurity ions should be settled as much as possible; then, Fe²⁺ should be oxidized to Fe³⁺ so as to obtain iron phosphate with higher purity in the next step of the precipitation process. The effects of the reaction temperature, seed crystals, pH value, and P/M on the precipitation process were investigated in detail. The experimental results show that in the reduced state, the optimal precipitation conditions are a temperature of 75 °C, an initial pH value of 4.5, and an optimal P/M molar ratio of 1.1. In the oxidized state, the optimal precipitation conditions are a temperature of 60 °C, a solution pH = 2.5, and a reaction time of 25 min. After calcination, the precipitate mainly consists of iron phosphate, which basically meets the requirements of an iron phosphate precursor. Full article

(This article belongs to the Special Issue Efficient and Green Recovery of Metal Minerals)

► Show Figures

Figure 1

11 pages, 987 KiB

Open AccessArticle

The Temporal Variation of Secondary Metabolites in the Mycobiont Culture and Thallus of Parmelina carporrhizans and Parmelina quercina Analyzed using High-Performance Liquid Chromatography

by David Alors, Pradeep Kumar Divakar, Anjuli Calchera, Imke Schmitt, Ana Crespo and María Carmen Molina

Separations 2023, 10(7), 399; https://doi.org/10.3390/separations10070399 - 11 Jul 2023

Viewed by 1615

Abstract

Lichens are composite organisms that produce a wide variety of secondary metabolites; many of the compounds have a high potential as bioactive compounds. The major limitations of using bioactive compounds from lichens is their slow growth rate and the damage to environmental populations [...] Read more.

Lichens are composite organisms that produce a wide variety of secondary metabolites; many of the compounds have a high potential as bioactive compounds. The major limitations of using bioactive compounds from lichens is their slow growth rate and the damage to environmental populations caused by massive collection. The alternative to the massive collection of lichens in the field is their culture under laboratory conditions. We chose two related lichen species of Parmeliaceae that produce similar metabolites and isolated from spores in cultures placed under axenic conditions for over 550 days. From these cultures, we sampled 35 mg of each species from different culture media at two sampling times. The samples were analyzed using high-performance liquid chromatography (HPLC) to detect and identify major compounds. We found no differences in the metabolites produced within the species in comparisons between different culture media. Our results show that the mycobiont cultures produced different secondary metabolites than those found in natural lichen thalli. Moreover, different secondary metabolites between species and different metabolites over time were observed. We conclude that mycobiont cultures are a promising alternative for determining bioactive compounds and enhancing the efficiency of growth and production. These could be a good option for eco-friendly metabolite production. Full article

► Show Figures

Figure 1

17 pages, 5327 KiB

Open AccessArticle

Fast Procedure for Removing Silver Species in Waters Using a Simple Magnetic Nanomaterial

by Yésica Vicente-Martínez, Moisés Ruiz-Mendieta, Manuel Caravaca-Garratón, Manuel Hernández-Córdoba and Ignacio López-García

Separations 2023, 10(7), 398; https://doi.org/10.3390/separations10070398 - 10 Jul 2023

Cited by 2 | Viewed by 1929

Abstract

The increase in the production and use of disinfectants containing silver atoms (in both its ionic and nanomeric forms) in their formulation, due to the global pandemic situation caused by COVID-19, has increased the presence of silver species in wastewater. Moreover, silver atoms [...] Read more.

The increase in the production and use of disinfectants containing silver atoms (in both its ionic and nanomeric forms) in their formulation, due to the global pandemic situation caused by COVID-19, has increased the presence of silver species in wastewater. Moreover, silver atoms are now considered as emerging pollutants in water. In this work, we propose a novel method for the instantaneous and simultaneous removal of ionic and nanomeric silver in water samples, using a previously unpublished methodology consisting of the in situ formation of magnetic nanoparticles in the aqueous samples to be treated. While the nanoparticle precursors react to form them, the silver atoms present in the sample are adsorbed onto them due to a strong electrostatic interaction. As the final nanoparticles are magnetic, they can be easily removed from the aqueous medium using a magnet, leaving the samples free of silver species. The innovative feature of the method is that the adsorbent is synthesized in situ, within the sample to be treated, making the approach a low-cost, easy-to-perform solution. Temperature, contact time, dose of Fe₃O₄, and concentration of nanomeric and ionic silver were investigated. The results showed that at 50 °C, 100% of both silver species were removed from the water samples simultaneously. The surface of Fe₃O₄ was characterized before and after the application of the removal process using energy-dispersive X-ray spectroscopy and Field Emission scanning electron microscopy. Adsorption kinetics and equilibrium isotherms studied reveal a Langmuir-type physicochemical process. The procedure has been applied to different water samples (river and drinking water) with excellent results, making the method a new standard for the removal of ionic and nanomeric silver. In addition, the nanoparticles formed could be recycled and reused for other analytical and decontamination purposes. Full article

(This article belongs to the Section Environmental Separations)

► Show Figures

Graphical abstract

16 pages, 3424 KiB

Open AccessArticle

Enhanced Oil Spill Remediation Using Environmentally Asymmetric Dicationic Ionic Liquids: Synthesis, Characterization, and Evaluation

by Rima D. Alharthy, C. E. El Shafiee, M. I. Nessim, R. I. Abdallah, Y. M. Moustafa, M. Wafeek, D. A. Ismail, M. M. H. Khalil and R. A. El-Nagar

Separations 2023, 10(7), 397; https://doi.org/10.3390/separations10070397 - 10 Jul 2023

Cited by 6 | Viewed by 1395

Abstract

The disastrous consequences for society—economically, environmentally, and socially—caused by oil spills encouraged us to treat this problem. The target of this work is to synthesize new amphiphilic dicationic ionic liquids (Ia, Ib, and Ic) and evaluate them spectroscopically and gravimetrically as potential oil [...] Read more.

The disastrous consequences for society—economically, environmentally, and socially—caused by oil spills encouraged us to treat this problem. The target of this work is to synthesize new amphiphilic dicationic ionic liquids (Ia, Ib, and Ic) and evaluate them spectroscopically and gravimetrically as potential oil spill dispersants at different temperatures to cover cold and warm areas. The synthesized ILs were well characterized by different tools for analysis of their surface activity and thermal stability. Ia, Ib, and Ic showed good dispersion effects, which were recorded to be 5.32, 20.45, and 33.61% for Ia, Ib, and Ic, respectively, at 10 °C and 12.28, 52.55, and 66.80% for Ia, Ib, and Ic, respectively, at 30 °C with a dispersant-to-oil ratio (DOR) of 0.8:10 (wt.%). Acute toxicity tests were elucidated against Nile tilapia and Oreochromis niloticus fish and confirmed their slight toxicity by determining a LC50 value greater than 100 ppm after 96 h, which recorded 13.25, 17.75, and 37.5 mg/L for Ia, Ib, and Ic, respectively. Overall, the new synthesized ILs can be represented as sustainable materials for toxic chemicals to disperse oil spills. Full article

(This article belongs to the Special Issue Advanced Techniques in the Separation Processes and Development of Novel Adsorbents)

► Show Figures

Figure 1

14 pages, 4988 KiB

Open AccessArticle

Anticorrosive Effects of Essential Oils Obtained from White Wormwood and Arâr Plants

by Ghada Beniaich, Mustapha Beniken, Rajae Salim, Nadia Arrousse, Elhachmia Ech-chihbi, Zakia Rais, Asmae Sadiq, Hiba-Allah Nafidi, Yousef A. Bin Jardan, Mohammed Bourhia and Mustapha Taleb

Separations 2023, 10(7), 396; https://doi.org/10.3390/separations10070396 - 10 Jul 2023

Cited by 5 | Viewed by 1806

Abstract

This article is part of the contribution to the development of two medicinal plants widely used by the Moroccan population: white wormwood (Artemisia herba-alba) andArâr (Juniperus phoenicea), species belonging to the Asteraceae and Cupressaceae families, respectively. The present work [...] Read more.

This article is part of the contribution to the development of two medicinal plants widely used by the Moroccan population: white wormwood (Artemisia herba-alba) andArâr (Juniperus phoenicea), species belonging to the Asteraceae and Cupressaceae families, respectively. The present work was conducted to investigate the chemical composition and anticorrosive properties of essential oils (EOs) extracted from these plants. The chemical analysis of the essential oils (EOs) was carried out by GC-MS/MS. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and quantum chemical calculations by density-functional theory at B3lYP were used to study the anticorrosive effect of the researched oils on mild steel in 1 M hydrochloric acid solution. Moreover, SEM-EDX analysis was used to identify the surface morphology of mild steel surface. GC-MSMS results showed the presence of 32 potentially active compounds in the EOs of Artemisia herba-alba. The average yield of the EOs was about 1.39 ± 0.17 mL/100 g dry matter. Beta thujone (30.07%) and alpha thujone (13.32%) are the main components, while for the EOs of Juniperus phoenicea, the study showed the presence of 30 constituents, with alpha-pinene (43.61%) and manoyl oxide (11.5%) as the main components. The average yield of HE was 1.10 ± 0.03 mL/100 g dry matter. The findings demonstrated an important anticorrosive action of EOs from Artemisia herba-alba and Juniperus phoenicea. Notably, the experimental results showed good efficiency of the studied essential oils and correlated well with the density-functional theory (DFT) calculations. The results of potentiodynamic polarization measurements showed that hydrazone acted as a mixed-type inhibitor. The EIS results showed an increase in charge transfer resistance accompanied by a noticeable decrease in C_dl values, revealing that both studied oils were effective as reliable inhibitors for the protection of mild steel in 1 M HCl solution. Also, the efficiency decreased with decreasing inhibitor concentrations. Surface studies ensure the effectiveness of both investigated oils and the reduction of the surface roughness of mild steel. Furthermore, DFT results of the major constituents of Artemisia herba-alba and Juniperus phoenicea EOs revealed insights into the chemical reactivity of the tested oils while supporting the experimental conclusions and showed outstanding adsorption ability of both investigated EOs on the steel surface. Full article

(This article belongs to the Special Issue Essential Oils: Extraction, Chemical Composition, and Biological Activity)

► Show Figures

Figure 1

17 pages, 3709 KiB

Open AccessArticle

Bacterial Endophytes from Moringa oleifera Leaves as a Promising Source for Bioactive Compounds

by Amr H. Hashem, Abdulaziz A. Al-Askar, Hamada Abd Elgawad and Amer M. Abdelaziz

Separations 2023, 10(7), 395; https://doi.org/10.3390/separations10070395 - 6 Jul 2023

Cited by 9 | Viewed by 2636

Abstract

Bacterial endophytes reside within the tissues of living plant species without causing any harm or disease to their hosts. Bacterial endophytes have produced a variety of bioactive compounds that can be used for different biomedical applications. In the current study, two bacterial endophytes [...] Read more.

Bacterial endophytes reside within the tissues of living plant species without causing any harm or disease to their hosts. Bacterial endophytes have produced a variety of bioactive compounds that can be used for different biomedical applications. In the current study, two bacterial endophytes were isolated from healthy Moringa oleifera leaves, and identified genetically as Stenotrophomonas maltophilia and Alcaligenes faecalis. Phytochemical results illustrated that A. faecalis produced phenolics at 547.2 mg/g, tannins at 156.7 µg/g, flavonoids at 32.8 µg/g, and alkaloids at 111.2 µg/g compared to S. maltophilia, which produced phenolics at 299.5 mg/g, tannins at 78.2 µg/g, flavonoids at 12.4 µg/g, and alkaloids at 29.4 µg/g. GC-MS analysis indicated that A. faecalis extract has 24 bioactive compounds, including 9 major compounds, namely octadecanoic acid, hexadecanoic acid, linoleic acid ethyl ester, octadecenoic acid, methyl ester, methyl stearate, nonacosane, indolizine, palmitoleic acid, and heptacosane. On the other hand, S. maltophilia extract has 11 bioactive compounds, including 8 major compounds, namely oleic acid, octadecanoic acid, hexadecanoic acid, cis-2-phenyl-1, 3-dioxolane-4-methyl, ergotamine, diisooctyl phthalate, diethyl phthalate, and pentadecanoic acid. To check the safety of these extracts, the cytotoxicity of Ethyl acetate (EA) extracts of S. maltophilia and A. faecalis were evaluated against the Vero normal cell line, and the results confirmed that these extracts are safe to use. Moreover, results revealed that EA extracts of S. maltophilia and A. faecalis exhibited anticancer activity against the cancerous MCF7 cell line, where IC₅₀ was 202.4 and 119.7 µg/mL, respectively. Furthermore, EA extracts of S. maltophilia had antibacterial and antifungal activity against Gram-positive and Gram-negative bacteria, and unicellular fungi. Likewise, the EA extract of A. faecalis exhibited antibacterial and antifungal activity against Gram-positive bacteria, as well as unicellular fungi, but did not show any activity against Gram-negative bacteria. Also, EA extracts of S. maltophilia and A. faecalis exhibited moderate antioxidant activity where IC₅₀ were 146.2 and 147.6 µg/mL, respectively. In conclusion, the two isolated endophytic bacteria S. maltophilia and A. faecalis have promising bioactive compounds that have antibacterial, antioxidant, and anticancer activities. Full article

(This article belongs to the Special Issue Separation, Analysis and Biological Evaluation of Bioactive Compounds)

► Show Figures

Graphical abstract

18 pages, 873 KiB

Open AccessArticle

A Multi-Approach Study of Phytochemicals and Their Effects on Oxidative Stress and Enzymatic Activity of Essential Oil and Crude Extracts of Rosmarinus officinalis

by Soumeya Bencharif-Betina, Nadjia Benhamed, Amina Benabdallah, Hamdi Bendif, Abderrahim Benslama, Carmine Negro, Gabriel Plavan, Omar H. Abd-Elkader and Luigi De Bellis

Separations 2023, 10(7), 394; https://doi.org/10.3390/separations10070394 - 6 Jul 2023

Cited by 4 | Viewed by 1915

Abstract

Rosmarinus officinalis or Rosemary is a highly valued medicinal vegetal, owing to its notable antispasmodic, anti-inflammatory, and antibacterial properties. In the current work, we aimed to identify the chemical components of the essential oil (EO) of R. officinalis and evaluate its biological properties [...] Read more.

Rosmarinus officinalis or Rosemary is a highly valued medicinal vegetal, owing to its notable antispasmodic, anti-inflammatory, and antibacterial properties. In the current work, we aimed to identify the chemical components of the essential oil (EO) of R. officinalis and evaluate its biological properties using an in vitro approach. High performance liquid chromatography time-of-flight mass spectrometry (HPLC-TOF-MS) was utilized to analyze of the hydro-methanolic extract (HME), while gas chromatography–mass spectrometry (GC/MS) was considered during the analysis of the EO’s chemical composition. The antioxidant abilities of HME and the EO were assessed using diverse tests (DPPH, ABTS, GOR, CUPRAC, and FRAP). The anti-enzymatic properties were tested by the inhibition of cholinesterases, α-glucosidase, and tyrosinase enzyme. The HPLC-TOF-MS displayed the existence of flavonoids like luteolin glucuronide I and II, and a few known hydroxycinnamic acids. The EO contained three major components, namely, eucalyptol (28.7%), camphor (16.7%), and borneol (13.5%). The HME had a high total polyphenol content, as determined by the Folin–Ciocalteau method (335.37 ± 9.33 µg of gallic acid eq·mg⁻¹). Notably, the analysis of the bioactivities of the HME and EO revealed comparatively that they possessed higher radical scavenging capacity in the DPPH, ABTS, and galvinoxyl assays, while EO exhibited a higher capacity for enzyme inhibition. Overall, our findings suggest that both the EO and HME extract of Algerian’s R. officinalis holds great usefulness in the pharmaceutical and nutraceutical fields due to its elevated polyphenol content and potent bioactivities. Full article

► Show Figures

Figure 1

14 pages, 2974 KiB

Open AccessArticle

A Prominent Streptomyces sp. Biomass-Based Biosorption of Zinc (II) and Lead (II) from Aqueous Solutions: Isotherm and Kinetic

by Sheetal Kumari, Nitin Kumar Agrawal, Animesh Agarwal, Anil Kumar, Neeraj Malik, Dinesh Goyal, Vishnu D. Rajput, Tatiana Minkina, Pinki Sharma and Manoj Chandra Garg

Separations 2023, 10(7), 393; https://doi.org/10.3390/separations10070393 - 4 Jul 2023

Cited by 11 | Viewed by 1537

Abstract

Traditional freshwater sources have been over-abstracted in the worldwide crisis of water scarcity. Effluents have extremely high amounts of Zn²⁺ and Pb²⁺, according to an investigation of wastewater samples taken from several industrial zones. However, these heavy metals are among [...] Read more.

Traditional freshwater sources have been over-abstracted in the worldwide crisis of water scarcity. Effluents have extremely high amounts of Zn²⁺ and Pb²⁺, according to an investigation of wastewater samples taken from several industrial zones. However, these heavy metals are among the most harmful to both humans and wildlife that are currently known. Streptomyces sp. is utilized in this study as a biosorbent to biosorb Zn²⁺ and Pb²⁺ from single and binary aqueous solutions. Several factors, such as biomass concentration (0.25–4 g), metal solution concentration (5–50 mg L⁻¹), solution pH (2–5), and contact time were standardized. Streptomyces sp. biomass was able to extract 93% Pb²⁺ and 91% Zn²⁺ from a single and 95% Pb²⁺ and 97% Zn²⁺ from a binary metal aqueous solution containing 25 mg L⁻¹ and pH 4. The highest adsorption capacity in both single and binary sorption experiments was determined to be shared by Zn²⁺ and Pb²⁺. The biosorbent’s metal adsorption increased from 0.48 to 4.56 mg g⁻¹ for Pb²⁺ and from 0.21 mg g⁻¹ to 4.65 mg g⁻¹ for Zn²⁺ when the metals were present singly, and from 0.44 to 4.18 mg g⁻¹ for Pb²⁺ and from 0.41 mg g⁻¹ to 5.67 mg g⁻¹ for Zn²⁺ when the metals were present in binary form. The amount of metal ions was raised from 5 to 50 mg L⁻¹. Correlation coefficient (R²) values indicate that the adsorption pattern for Zn²⁺ and Pb²⁺ followed Freundlich isotherm R² > 0.9543 for single and 0.9582 for binary sorption system. In order to remove Zn²⁺ and Pb²⁺ from an aqueous solution, Streptomyces sp. is a potential and different source of adsorbents. Full article

(This article belongs to the Special Issue Development of Mesoporous Materials for Adsorption and Recovery of Metals)

► Show Figures

Figure 1

19 pages, 4758 KiB

Open AccessArticle

Remediation of Amitriptyline Pharmaceutical Wastewater by Heteroatom-Doped Graphene Oxide: Process Optimization and Packed-Bed Studies

by Wan Ting Tee, Jasmine Chua, Jia En Yong, Billie Yan Zhang Hiew, Suyin Gan and Lai Yee Lee

Separations 2023, 10(7), 392; https://doi.org/10.3390/separations10070392 - 3 Jul 2023

Cited by 3 | Viewed by 1815

Abstract

Amitriptyline residue released into the aquatic ecosystem can have detrimental consequences on marine organisms and human wellbeing via consumption of polluted water. With a uniquely large surface area and abundant functionalities, graphene oxide adsorption offers a remediation solution for such water pollution. This [...] Read more.

Amitriptyline residue released into the aquatic ecosystem can have detrimental consequences on marine organisms and human wellbeing via consumption of polluted water. With a uniquely large surface area and abundant functionalities, graphene oxide adsorption offers a remediation solution for such water pollution. This study focused on synthesizing a novel graphene-based adsorbent via ice-templating of boron-doped graphene substrate. The batch adsorption performance of the as-synthesized adsorbent was explored by central composite design (CCD), while its potential large-scale application was evaluated with a packed-bed column study. The CCD optimized conditions of 12.5 mg dosage, 32 min adsorption time, 30 °C operating temperature and 70 ppm concentration produced the highest removal efficiency of 87.72%. The results of the packed-bed study indicated that continuous adsorption of amitriptyline was best performed at a graphene bed of 3.5 cm in height, with 100 ppm of the pharmaceutical solution flowing at 2 mL/min. Furthermore, the breakthrough curve was effectively portrayed by the Log Bohart–Adams model. The as-synthesized adsorbent showed a high regeneration potential using ethanol eluent via multiple adsorption–desorption cycles. The results suggest the boron-doped graphene adsorbent in packed-bed as a highly effective system to remediate amitriptyline in an aqueous environment. Full article

(This article belongs to the Section Environmental Separations)

► Show Figures

Graphical abstract

13 pages, 2020 KiB

Open AccessArticle

Stability-Indicating Quantification of Ciprofloxacin in the Presence of Its Main Photo-Degradation Product by CZE and UPLC: A Comparative Study

by Alhumaidi B. Alabbas and Sherif A. Abdel-Gawad

Separations 2023, 10(7), 391; https://doi.org/10.3390/separations10070391 - 3 Jul 2023

Cited by 2 | Viewed by 2262

Abstract

Active pharmaceutical ingredients (APIs) can be assured to be safe and effective with the help of stability-indicating procedures. An accurate comparison comprising the utilization of capillary zone electrophoresis (CZE) and ultra-performance liquid chromatography (UPLC) for the sensitive and accurate measurement of ciprofloxacin (CPF) [...] Read more.

Active pharmaceutical ingredients (APIs) can be assured to be safe and effective with the help of stability-indicating procedures. An accurate comparison comprising the utilization of capillary zone electrophoresis (CZE) and ultra-performance liquid chromatography (UPLC) for the sensitive and accurate measurement of ciprofloxacin (CPF) in the presence of its major photo-degradation product was conducted. The CZE and UPLC working conditions were optimized to obtain the best pattern of separation for CPF and its photo-degradant. The linearity range of the cited techniques was confirmed to be 0.5 to 50 µg/mL. A thorough validation scheme according to the ICH-Q2B criteria was performed, including linearity, accuracy, precision, robustness, detection, and quantification limits. Selective quantification of CPF in the presence of up to 90% of its main photo-degradant was carried out using the proposed methods. For the analysis of CPF in tablet and intravenous (I.V.) solution forms, the CZE and UPLC procedures were applied. The suggested methods can be applied to keep an eye on the safety and efficacy of CPF in either bulk or dosage forms. Full article

(This article belongs to the Special Issue Analysis of Natural Products and Synthetic Drugs by HPLC or HPTLC)

► Show Figures

Figure 1

18 pages, 3155 KiB

Open AccessEditor’s ChoiceReview

Advances in Cork Use in Adsorption Applications: An Overview of the Last Decade of Research

by João Jesus, Raquel Nunes da Silva and Ariana Pintor

Separations 2023, 10(7), 390; https://doi.org/10.3390/separations10070390 - 3 Jul 2023

Cited by 5 | Viewed by 2641

Abstract

Cork-based adsorbents have been gathering interest from the research community since the 1990s. A first review was published on this topic in 2012. Still, in the last decade, novel activated carbons and biochars, in multiple applications, have been produced using cork as a [...] Read more.

Cork-based adsorbents have been gathering interest from the research community since the 1990s. A first review was published on this topic in 2012. Still, in the last decade, novel activated carbons and biochars, in multiple applications, have been produced using cork as a raw material. This review presents these novel insights into the properties of cork, in its various forms, and how they relate to adsorption capacity. Details on new preparation methodologies and respective characteristics of cork-based activated carbons and biochars are thoroughly compared, and patterns are identified. Finally, the adsorption capacity of these materials in experimental conditions is reviewed for different compounds: heavy metals, organics, and gaseous pollutants. This review provides a complete picture of the kind and quality of different cork forms, their relative economic value, and how their conversion into activated carbons and biochars can contribute to a more circular economy by producing adsorbents that aid in the reduction of multiple pollution types. Full article

(This article belongs to the Special Issue Removal of Metals or Other Toxic Substances from Wastewaters by Natural Sorbents)

► Show Figures

Graphical abstract

16 pages, 9650 KiB

Open AccessArticle

Adsorption Studies of Pb(II) and Cd(II) Heavy Metal Ions from Aqueous Solutions Using a Magnetic Biochar Composite Material

by Virendra Singh, Nidhi Pant, Rajat Kumar Sharma, Diwakar Padalia, Pankaj Singh Rawat, Rabina Goswami, Praveen Singh, Akhilesh Kumar, Prabhakar Bhandari, Alam Tabish and Ahmed Mohamed Deifalla

Separations 2023, 10(7), 389; https://doi.org/10.3390/separations10070389 - 2 Jul 2023

Cited by 14 | Viewed by 3446

Abstract

Heavy metal toxicity in water is a serious problem that may have harmful effects on human health and the ecosystem. Lead [Pb(II)] and cadmium [Cd(II)] are two such heavy metal ions, present in water, whose severity is well-known and well-studied. In the current [...] Read more.

Heavy metal toxicity in water is a serious problem that may have harmful effects on human health and the ecosystem. Lead [Pb(II)] and cadmium [Cd(II)] are two such heavy metal ions, present in water, whose severity is well-known and well-studied. In the current research, magnetic biochar composite (MBC) is studied as an adsorbent material for the effective removal of lead and cadmium ions from water solutions. Magnetite (Fe₃O₄) nanoparticles and pine-needle-derived ultrasonicated magnetic biochar were used in different weight ratios to prepare APTES (3-aminopropyl triethoxysilane)-functionalized MBC (FMBC). An average crystalline size of ~10 nm for magnetite NPs was obtained via XRD analysis. The adsorption characteristics of both Pb(II) and Cd(II) ions were investigated in a batch experiment. The FTIR spectra of raw biochar, MBC, FMBC, and metal-loaded FMBC were obtained at different stages. The decrease in the intensity of the –NH₂ functional group in the FTIR spectra of the residue confirmed the successful adsorption of heavy metal ions. The SEM-EDX spectra of the residue showed the uniform adsorption of Pb(II) and Cd(II) heavy metal ions onto the surface of the adsorbent. Magnetic biochar composite (MBC) was found to be a very effective adsorbent at basic pH, as a maximum of 97% instantaneous heavy metal removal was observed for both ions in synthetic water solutions. The Langmuir isotherm model predicted the monolayer adsorption and good affinity between the metal ions and adsorbent. The prepared MBC is low-cost, environmentally friendly, and it has shown good adsorption performance. Therefore, our study suggests that the magnetic biochar composite under study is an effective adsorbent for lead and cadmium metal ion removal from aqueous solutions at normal room temperature. Only a few hundred milligrams of the adsorbent dose is sufficient to remove higher concentrations (~100 ppm) of lead and cadmium at basic pH conditions of aqueous solutions. Full article

(This article belongs to the Section Purification Technology)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Separations, Volume 10, Issue 7 (July 2023) – 53 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI