Search Results (648)

This work performed a sensitivity analysis based on a conventional extractive distillation system to thoroughly evaluate the cost of separating bioethanol from water. The analysis considers the compositions and production volumes that are likely to result from the fermentation process of various biorefineries, regardless of their specific generation. It also outlines how the cost of bioethanol purification decreases as the ethanol concentration in the fermentation broth increases. For each composition-flow point in a gridded workspace, a distillation train was designed using the Aspen Plus^® simulation framework, focusing on minimizing the total annual cost. The results are discussed graphically, illustrating total annual costs and specific column costs in relation to feed stream composition and inflow. The findings quantitatively demonstrate that the cost of separation per mass unit of anhydrous ethanol decreases with higher inflow and increased input ethanol concentration. Additionally, it is evident that the primary cost is associated with the preconcentrator column. Full article

One of the major current societal challenges concerns the reuse of waste materials and valuable substances to mitigate the environmental impact of human activities, which has led to the increasing release of pollutants, from plastics to pharmaceuticals. In this study, we report a simple recycling strategy for surgical masks to obtain an activated carbon-like material, suitable for the solid-phase extraction (SPE) of Phthalic acid esters (PAEss) from plastic bottled water. The sorbent was produced by high-temperature calcination after sulfuric acid treatment to enhance the thermal stability of polypropylene. The sorbent was characterized by thermal analysis, Raman spectroscopy, FTIR and scanning electron microscopy. SPE was used to preconcentrate the analytes, and the main parameters affecting the extraction, such as pH, sorbent amount, organic modifier percentage, ionic strength and elution volume, were optimized. PAEs were determined by UHPLC-PDA under gradient elution. The developed method was linear in the range 0.25–1000 ng/mL, with LOQs between 0.25 and 0.10 ng/mL and LODs between 0.008 and 0.003 ng/mL. Recovery ranged from 95.9 to 104.7%, the precision expressed as RSD% was below 7.32, and the accuracy expressed as BIAS% ranged from −5.75 to 5.93. The proposed approach provides a simple and low-cost valorization route for PPE waste, while enabling reliable PAEs analysis in drinking water. Full article

The manuscript describes an optical sensing microplate for the high-throughput screening of imidazolinone herbicides in soil extracts. As far as we know, imprinted proteins (IPs) specific to imidazolinone herbicides have not been synthesized and used as a recognition element for their solid-phase extraction before. Imprinted bovine serum albumin (BSA) and glucose oxidase (GOx) were synthesized in the presence of imazamox as a template and then these IPs were immobilized at the bottom of microplate wells. The sorption capacity (Q) of aminated silica nanoparticles modified by IPs (IP–BIS) was 6.38 mg g⁻¹ while the imprinting factor ($IF$) equaled 2.6. The concentration of imazamox was determined by a “turn-off” solid-phase assay using alloyed CdZnSeS/ZnS quantum dots (QDs) as a component of fluorescent substrate. Alloyed CdZnSeS/ZnS QDs were stabilized in an aqueous phase by positively charged cysteamine that, as far we know, had not been used as this type of ligand before. Our method allows for determining the concentration of imazamox in the range of 0.5–9.2 μg mL⁻¹, with a limit of quantification limit of quantitation (LOQ) equal to 0.45 μg mL⁻¹ The sensing microplate enables parallel detection of up to 96 samples containing herbicides using standard fluorescence microplate readers or smartphones. The paper describes how such sensing microplates can be used for the analysis of artificially contaminated soil samples. The proposed approach combines pre-concentration of analyte at the IPs with its subsequent determination on a single analytical platform, thus allowing for both highly sensitive determination in laboratory conditions and mass screening in the field. Full article

Ensuring the simple, rapid, and real-time monitoring of the freshness of fresh food items is essential for maintaining food safety. By reacting with characteristic substances generated during spoilage, pH-responsive indicators can effectively reveal the degree of food freshness. In this study, a mixture of hydroxypropyltrimethyl ammonium chloride chitosan (HACC), polyvinyl alcohol (PVA), and blueberry anthocyanins (BAs) was adopted and, via an electrospinning strategy, changed into a membrane coupled with a pH-responsive ability to assess the freshness of shrimp. The results showed that HACC/PVA-BA membranes with a HACC: PVA ratio of 1:4 exhibited enhanced hydrophobicity, better WVP properties (4.32 × 10⁻⁹ g m⁻¹ s⁻¹ Pa⁻¹), a rapid pH-response ability within 5 s and super radical scavenging capacity (56.34% for DPPH and 54.74% for ABTS radicals). HACC’s immutable positive charge creates a strong electrostatic field that pre-concentrates spoilage-generated ammonia and intensifies the protonation state of BAs, which dramatically enhances colorimetric sensitivity and rapid response to volatile amines. Moreover, a satisfactory antibacterial ability for S. aureus and E. coli were also evidenced: HACC/PVA-BA (1:4) membranes achieved a maximum inhibition rate of 64.9% for E. coli and 62.2% for S. aureus. Once applied to monitor the freshness of shrimp stored at 4 °C, the HACC/PVA-BA (1:4) membranes were able to indicate shrimp freshness through visually recognizable color changes within 3 h, which correlated strongly with the spoilage indicators of total volatile basic nitrogen, total viable count, and pH value. It is suggested that the intelligent pH-responsive membranes show great potential for practical application in monitoring food freshness. Full article

Uranium ore preconcentration is a critical step in achieving environmentally sustainable uranium mining and reducing the operational load of hydrometallurgical processing systems. Conventional radioactive sorting systems predominantly employ a “single-ore-particle intermittent measurement” mode. Under continuous ore flow and high-throughput operating conditions, however, the radiation fields of adjacent ore particles inevitably overlap, which results in gamma-counting interference and blurred ore-segment boundaries, thereby limiting sorting accuracy and system capacity. To address these challenges, this study established a convolutional model that describes the relationship between ore-grade distribution and gamma-response characteristics under continuous ore flow conditions. On this basis, a deconvolution-based method for uranium ore grade calculation was proposed, and an adaptive determination strategy for the characteristic parameter α was introduced to improve grade estimation accuracy and enable reliable identification of ore-segment boundaries. The experimental results showed that, for uranium grades ranging from 0.05% to 0.18% and ore-segment lengths of 16–40 cm, the relative errors between the inverted and true grades of individual segments were all less than 10%. Compared with conventional intermittent measurement and identification schemes, the proposed method achieves stable and accurate grade inversion under conditions of overlapping radiation fields in continuous ore segments. Full article

In-tube solid-phase microextraction (IT-SPME) is an advanced microextraction technique in which a sample solution flows through a capillary containing an internal stationary phase, enabling efficient extraction and preconcentration of target analytes. The online coupling to liquid chromatography is a key advantage of this technique, enabling full automation and high analytical throughput, both of which are significant for food analysis. Recent advances have focused on developing novel sorbent materials that respond to external stimuli (e.g., magnetic, electrical, or thermal) and on integrating them into emerging chromatographic platforms. Moreover, key operational parameters, including sample volume, pH, phase thickness, and the capillary’s dimensions (length and inner diameter), must be optimized to achieve enhanced selectivity, speed, and sensitivity. Despite this, the literature still lacks updated reviews of SPME concepts and their innovations for versatile applications in food matrices. Hence, this review outlines the fundamental principles of IT-SPME while highlighting key parameters that affect analytical performance. Finally, we provide a literature review of SPME applications in food analysis over the past 6 years, while exploring current trends and future directions for SPME development and enhanced applications in food science. Full article

Increasing constraints related to water consumption and operational complexity have intensified interest in dry coal beneficiation as an alternative to conventional wet cleaning, particularly for low-calorific coals used in thermal power plants. In this study, the performance of a gravity-based dry beneficiation process using an air table was experimentally investigated for run-of-mine coals from the Soma Coal Basin, utilized in the Soma A Thermal Power Plant. The coal was crushed to −10 mm and classified into three size fractions, 5–10 mm, 3–5 mm, and 1–3 mm, before beneficiation. A pilot-scale air table with a capacity of 10 t/h was employed, and operating parameters including table inclination, airflow rate, and vibration frequency were optimized for each size fraction. Clean coal yields of 86.8–88.7% were achieved, while the ash content was reduced from 32 to 35% in the feed to 27.8%–29.7% in the clean coal (dry basis), remaining within the acceptable ash limits of the boiler design. The reject fractions exhibited high ash contents of approximately 71%–72%, indicating effective de-stoning and removal of high-density gangue minerals. Low and consistent E_p values (0.05–0.06) together with nearly constant cut-point densities (D₅₀ ≈ 1.82%–1.83 g/cm³) demonstrated sharp and stable density-based separation. The dust fraction remained limited (1.4%–2.1%), confirming mechanically stable operation. The removal of approximately 10% of the feed as high-density reject was found to reduce coal milling energy demand and lower the energy consumption of ash handling and disposal systems. Overall, the results show that air table-based dry beneficiation enables water-free and energy-efficient pre-concentration of low-calorific coals, offering strong potential for application in water-scarce regions. Full article

This work reports the synthesis and photocatalytic performance of TiO₂–MgO/kaolinite nanocomposites for the degradation of crystal violet (CV) and butyraldehyde under UV irradiation. MgO incorporation enhanced charge separation by limiting electron–hole recombination, while the halloysite-type kaolinite support increased surface area and improved dispersion of the active phases. The materials exhibited strong synergy between adsorption and photocatalysis, as the clay support pre-concentrated pollutants and facilitated their rapid degradation. The composite containing 10 wt% MgO (TK10) showed the highest efficiency, achieving 99.8% CV removal and outperforming commercial P25. The catalyst also demonstrated efficient degradation of gaseous butyraldehyde, highlighting its dual applicability for water and air purification. Kinetic analysis indicated a pseud-second-order adsorption mechanism, and isothermal data fitted the Langmuir model, suggesting monolayer adsorption. The TK10 composite showed excellent stability and reusability over multiple cycles, underscoring its potential as a cost-effective and environmentally benign photocatalyst for integrated environmental remediation. Full article

Development of novel methods for the separation, characterization, and analysis of microplastics is an urgent task. Countercurrent chromatography (CCC) has been proven to be an efficient method for the separation and preconcentration of microplastics from aqueous samples using two-phase water–oil systems. However, the efficiency of separation of microplastics from natural seawater by CCC has not been studied so far. Here we demonstrate the high efficiency of separation of microplastics from Black Sea water samples by CCC. The separation efficiency of PE, PP, PS, PVC, PET microparticles of different size (<63, 63–100, 100–250 μm) from spiked seawater samples is about 100%. The method enables the separation of microplastics with size at least down to 1 μm to be performed. The combination of CCC and pyro-GC-MS was applied to the quantification of microplastics in Black Sea water samples. Seven microplastics (μPE, μPP, μSBR, μPVC, μPET) were determined in the seawater samples under study. The total concentration of determined microplastics was about 6.5 μg/L. It was shown that the combination of CCC and pyro-GC-MS enabled robust analytical data to be obtained and hence can be applied to an accurate quantification of microplastics in seawater. Full article

Waste deposits from the Iberian Pyrite Belt that are rich in pyrite are a valuable secondary resource for getting back sulphide minerals and important metals that go with them. This study assessed the efficacy of a Multi-Gravity Separator (MGS) in concentrating pyrite and related polymetallic minerals from sulphide waste material sourced from the Alonso mining district (Huelva, Spain). Bench-scale MGS tests were done on two particle size fractions (−500 µm and −50 µm) to see how the speed of the drum rotation, the angle of the tilt, and the flow rate of the wash water affected the separation efficiency. Mineral Liberation Analysis (MLA) showed that both size fractions had about 65.8 wt% pyrite, but the −50 µm fraction was much more liberated. Under the best operating conditions, the MGS was able to recover about 58% of the pyrite from the −500 µm fraction and about 64% from the −50 µm fraction. The mass recoveries were about 38% and 42%, respectively. There was also a better recovery of related metals like Co, Cu, Zn, and Mn, especially for the finer fraction. This shows the improvement of the liberation and stratification behaviour. The results show that MGS is a good way to pre-concentrate fine-grained pyrite-rich waste. The performance is heavily influenced by the size distribution of the particles and the operating parameters. These results suggest that improvements in gravity separation may offer a long-term pathway for the recycling of sulphide mine waste within a circular economy. Full article

The separation of rare earth elements (REEs) with similar chemical properties remains a relevant challenge today, most often addressed using liquid–liquid and solid-phase extraction with various chelating agents. Excellent complexing agents for REEs are 1,3-diketones and their analogs. We have for the first time proposed a method for preparing a material consisting of a covalently immobilized 3-acyl-4-hydroxycoumarin ligand on silica. For its synthesis, we employed a strategy based on the “click” reaction of 3-azidopropyl silica with a propargyl-containing coumarin–chalcone conjugate—this approach is the most tolerant and does not affect the coordinationally active fragment of the ligand. The material was characterized by thermal analysis, IR spectroscopy, and ¹³C NMR. The potential of the synthesized material for REE preconcentration was demonstrated at pH 5–5.5: high extraction efficiency for Gd(III), Dy(III), Er(III), Eu(III), Sm(III), and Yb(III) was observed, with fast adsorption kinetics (30 min) and extraction degrees of ~98%. Under unified conditions of static and dynamic extraction for Gd(III), Dy(III), Er(III), Eu(III), Sm(III), and Yb(III), affinity series toward the surface were obtained as a function of the distribution coefficient. It was shown that 10-fold molar excesses of Fe(III), Al(III), Cu(II), Ni(II), and Co(II) allow retention of more than 95% extraction for Dy(III) and Er(III). After adsorption of Dy(III) and Er(III), shifts in the carbonyl group absorption bands are visible in the IR spectra of the material, indicating a chelating mechanism of sorption. Additional studies are required for implementation in analytical and preparative REE separation schemes; however, preliminary data show that the material is a highly active adsorbent. Full article

This study investigated lithium beneficiation from nepheline syenite ore containing 242.57 ppm Li, identifying biotite as the primary lithium-bearing mineral. A high-intensity dry magnetic separation produced a pre-concentrate assaying at approximately 850–1000 ppm Li, and flotation tests were conducted on both the run-of-mine ore and this magnetic product. Flotation performance was systematically evaluated using two top sizes (−500 and −300 µm), six size fractions (−500 + 75, −500 + 53, −500 + 38, −300 + 75, −300 + 53, −300 + 38 µm), four pH values (2.5, 4.0, 6.5, 9.5), and three collectors (DAHC, Derna 7, and Der A4). Among the reagents, Der A4 yielded the most promising results. Optimization using sodium silicate as a depressant demonstrated that, at 20 g/t Der A4, 500 g/t Na₂SiO₃, and pH 4.0, the −300 + 75 µm fraction of the run-of-mine ore reached approximately 5300 ppm Li. Applying the same parameters to the magnetic pre-concentrate resulted in a 6326.46 ppm Li concentrate with roughly 80% of flotation recovery. Mineralogical characterization using MLA, XRD, modal mineralogy, and SEM-EDS confirmed that the optimized product consisted predominantly of biotite, accompanied by K-feldspar, nepheline, and albite. Liberation results showed high liberation levels and the free surface, supporting the efficiency of combining magnetic separation with flotation for upgrading nepheline syenite as a potential lithium resource. Full article

Metal–organic framework (MOF)-based surface-enhanced Raman scattering (SERS) sensors have emerged as a versatile platform for high-sensitivity and selective detection in agricultural, environmental, and biomedical applications. By integrating plasmonic nanostructures with tunable MOF architectures, these hybrid systems combine ultrahigh signal enhancement with molecular recognition, analyte preconcentration, and controlled hotspot distribution. This review provides a comprehensive overview of the fundamental principles underpinning MOF–SERS performance, including EM and chemical enhancement mechanisms, and highlights strategies for substrate design, such as metal–MOF composites, plasmon-free frameworks, ligand functionalization, and hierarchical or core–shell architectures. We further examine their applications in environmental monitoring, pesticide and contaminant detection, pathogen identification, biomarker analysis, and theranostics, emphasizing real-sample performance, molecular selectivity, and emerging integration with portable Raman devices and AI-assisted data analysis. Despite notable advances, challenges remain in reproducibility, quantitative reliability, matrix interference, scalability, and biocompatibility. Future developments are likely to focus on rational MOF design, sustainable fabrication, intelligent spectral interpretation, and multifunctional integration to enable robust, field-deployable sensors. Overall, MOF-based SERS platforms represent a promising next-generation analytical tool poised to bridge laboratory innovation and practical, real-world applications. Full article

Metal-organic frameworks (MOFs) are porous crystalline materials composed of metal ions and organic ligands. By varying the combinations of metal centers and ligands, their structural properties, adsorption performance, and stability in aqueous environments can be tuned. Owing to these characteristics, MOFs have attracted attention as promising materials for environmental analysis and separation technologies. In this study, several MOFs with different metal ions and ligands were synthesized and evaluated for their adsorption performance for bensulfuron-methyl, a sulfonylurea herbicide. Among the tested MOFs, MIL-53(Al) exhibited the highest recovery. The results indicate that adsorption performance depends on the combination of metal ions and organic ligands. Full article

Microplastic pollution is a growing global environmental and public health concern, driven by the increasing production and use of plastics. Due to their ubiquitous presence in the environment, humans and animals may be exposed to micro- and nanoplastics via several possible routes. For micro- and nanoplastics, the development of standardized and validated methods remains an important area of progress to support human health risk assessments. In order to monitor micro/nanoplastics’ occurrence in organisms and the environment, it is necessary to develop accurate and reliable methods to quantify and characterize micro/nanoplastics from various biological and environmental matrices. In this study, an analytical, multi-platform approach was established to characterize and quantify polystyrene nanoplastics in biological samples through a combination of sample pre-concentration, asymmetric flow field-flow fractionation, ultraviolet–visible light, dynamic light scattering detectors and pyrolysis–gas chromatography–mass spectroscopy. Several digestion methods on various rodent tissues were tested and modified, and these led to the development of tissue-specific protocols to maximize yield. These digestion protocols were then combined with a new method of concentrating and retaining plastics to prevent the loss of submicron particles. For identification and quantification, known amounts of polystyrene nanoplastics were spiked into rodent tissues (intestine, kidney and liver). This was followed up by a mouse in vivo study consisting of a single dose of PS-NPs, followed by tissue collection, digestion and analysis. Polystyrene particles were detected in the liver and kidney, but not reliably in the intestinal tissues. Full article