This study developed a detection method for hymexazol residues in sugar beet, targeting its low molecular weight, high polarity, and lack of chromophores. The method optimized mass spectrometry conditions, liquid chromatography parameters, and extraction/purification protocols to address the matrix characteristics of sugar beet. Specifically, the sample pretreatment involved extraction with acetonitrile, followed by purification using GCB, silica, and C18 sorbents to minimize matrix interference. Sensitivity was enhanced by reducing flow rate and spray voltage. The method demonstrated high performance and was applied to analyze real samples. The LOD and LOQ were theoretically determined to be 1.22 and 3.80 μg/kg, respectively, using the blank standard deviation method. At the spiked levels of 5.0, 10, and 50 μg/kg, the intraday and interday recoveries were 80.2–97.9% and 78.1–101.7%, with corresponding RSDs of 4.8–6.4% and 4.6–8.8%, respectively. These results could meet the requirements for pesticide residue analysis and regulatory monitoring.
A simple and efficient QuEChERS-HPLC-DAD method was developed and validated for the simultaneous determination of benzoic acid, sorbic acid, and eight parabens in diverse food matrices. The sample preparation procedure was systematically optimized by evaluating the extraction solvent composition, salting-out conditions, and dispersive solid-phase extraction clean-up to achieve satisfactory recoveries while minimizing matrix interferences. Chromatographic separation was accomplished using isocratic elution on a C18 column with dual-wavelength ultraviolet detection, enabling the simultaneous determination of both authorized preservatives and non-authorized parabens within a single analytical run. The validated method exhibited excellent linearity (R2 > 0.996), low to moderate matrix effects (within ±20%), satisfactory recoveries (79–112%), and good precision (RSD < 7.3%), meeting the performance criteria for routine residue analysis. The applicability of the method was demonstrated by analyzing commercial food samples from six food categories. Benzoic acid and sorbic acid were the most frequently detected preservatives, whereas only methylparaben and propylparaben were identified among the investigated parabens. No non-authorized parabens were detected in the analyzed samples. Owing to its simplicity and reliability, the proposed QuEChERS-HPLC-DAD method represents a practical analytical approach for routine multi-matrix monitoring of food preservatives in quality control and food safety laboratories.
A circular economy for polyethylene terephthalate (PET) aims to achieve complete material recirculation and reduce dependence on fossil-based feedstocks. Among recycling strategies, depolymerization offers the greatest potential for true circularity. This work investigates deep eutectic solvent (DES)-assisted PET depolymerization using a tetrabutylammonium bromide/sulfolane (TBABr/Sulf) system. A four-factor, three-level Box–Behnken design was employed, where reaction time, NaOH concentration, PET/solvent ratio, and water content were selected as independent variables, with PET weight loss as the response. The optimized conditions of 35 min reaction time, 5.9 wt% NaOH, a PET/solvent ratio (g/g) of 0.061, and a 1:1 water-to-DES ratio achieved 97% PET depolymerization and 93.8% TPA recovery. The process achieved a relatively low PET/DES (g/g) utilization ratio of 0.12 and required at least 40% less NaOH than other DES-based alkaline hydrolysis reported in the literature. The identity and quality of the recovered TPA were confirmed by FTIR, NMR, DSC, and elemental analysis. Under microwave-assisted conditions, TBABr/Sulf was successfully reused over three consecutive cycles while maintaining 100% depolymerization efficiency with consistent TPA quality. Collectively, these results demonstrate the technical potential of the proposed DES-assisted PET depolymerization process, particularly in terms of reduced solvent and alkaline requirements, shortened reaction time, and demonstrated solvent recyclability.
Germanium is a strategically critical metal with indispensable applications in infrared optics, fiber-optic communications, and semiconductor devices. Although previous reviews have extensively addressed the hydrometallurgical recovery of germanium from specific enriched materials and the associated extraction efficiencies, a systematic and integrated understanding of its migration behavior, occurrence states, and phase transformations across the entire zinc smelting process is still lacking. This review fills this gap by investigating the migration and enrichment characteristics of germanium in zinc smelting residues and by constructing a comprehensive framework encompassing occurrence, roasting, leaching, separation, and purification, covering the entire route from zinc concentrate to high-purity germanium production. By establishing this integrated analytical framework that traces the migration and enrichment pathways throughout the whole process chain, this review provides a valuable technical reference for elucidating the migration patterns of germanium in complex smelting systems, devising efficient recovery strategies, and advancing the sustainable utilization of germanium resources.
The global energy transition and rapid electrification are driving increased demand for copper. However, conventional pyrometallurgical and hydrometallurgical extraction routes are increasingly challenged by declining ore grades and stricter environmental regulations. Bioleaching involves the microbial catalysis of sulfide mineral dissolution and provides a sustainable method for copper recovery from low-grade ores, tailings and secondary resources. This review provides a critical and integrated analysis of copper sulfide bioleaching, covering microbial diversity, molecular mechanisms, mineralogical controls, operational parameters, and industrial applications. This review also examines the functional roles of prominent acidophiles, including the functional roles of prominent acidophiles, including Acidithiobacillus spp., Leptospirillum spp. and thermophilic archaea, in the oxidation of iron and sulfur, mitigation of passivation, and metal solubilization. The molecular underpinnings of these processes are explored by investigating iron and sulfur oxidation gene networks (the rus operon and sox cluster), copper resistance systems (CopA, CusCBA) and biofilm formation pathways. The mineralogical controls on the behavior of chalcopyrite (refractory/passivating), chalcocite (highly reactive) and bornite (intermediate) are critically assessed. The synergistic effects of key operational parameters (temperature, pH, redox potential, aeration and particle size) on leaching kinetics and microbial community dynamics are investigated. The scalability, efficiency and environmental footprint of industrial applications such as heap, dump, stirred-tank and in situ bioleaching are discussed. Despite more than four decades of commercial development, several challenges remain, such as slow chalcopyrite dissolution, passivation, metal toxicity, and scale-up limitations. Emerging solutions such as synthetic microbial consortia, multi-omics technologies, artificial intelligence-assisted optimization, and digital twins are identified as transformative approaches for next-generation biomining. In this review, microbiology, mineralogy, electrochemistry, and process engineering are integrated to demonstrate that biotechnological leaching is among the most promising technologies for the sustainable production of copper and to identify future directions for its industrial application.
Reversed-phase chromatography stationary phases (such as C18) are widely used in commercial high-performance liquid chromatography (HPLC). However, when dealing with complex mixtures, they often exhibit limited separation capabilities and peak tailing phenomena. To address this problem, two novel HPLC stationary phases based on polyamine macrocycles were developed. A trianglamine macrocyclic stationary phase (TRI-Sil) was first prepared using chlorinated silica gel as the support, which can effectively separate a variety of aromatic compounds, but with limited selectivity for positional isomers such as phenylenediamine. To further improve the separation selectivity, a polyamine-silica macrocyclic stationary phase (CPAM-Sil) was synthesized by introducing a branched-chain-containing monomer. Under optimized conditions, CPAM-Sil achieved baseline separation of phenylenediamine and phenylenediol positional isomers and improved the separation of terphenyl isomers, with favorable asymmetry factors and high column efficiency compared with the commercial C18 column. Molecular docking confirmed multiple interactions such as electrostatic interactions and hydrogen bonding between the polyamine macrocycle (CPAM) and analytes. The CPAM-Sil column also exhibited good reproducibility and stability, showing promising potential for industrial application in chromatographic separation.
A new efficient coupled process to produce green solvent ethyl propionate was developed, which involved a fixed-bed reactor and pervaporation membrane separation. Firstly, the esterification reaction alone was investigated to explore reaction conditions and kinetics. Secondly, the pervaporation alone was investigated to explore separation conditions and the separation performance of pervaporation membranes. Then, the esterification reaction, coupled with pervaporation to enhance the reaction process, was investigated. Finally, the mathematical model of the esterification reaction, coupled with the pervaporation process, was established. The results showed that the conversion of ethanol reached 78.4% within 5 h. The reaction kinetics were obtained based on the pseudo-homogeneous (PH) model. Under the condition of a circulation flow rate of 100 L/h, the influence of concentration polarization could be well overcome, and a high level of pervaporation could be achieved. The pervaporation coefficients of the four-component system were obtained based on Fick’s law. The dehydration rate increased significantly with the increase in pervaporation temperature, which could effectively enhance the esterification reaction. The model could well predict the experimental results, and the experimental results were in good agreement with the theoretical calculations.
Gas–solid fluidized bed separation uses upward gas flow to fluidize a dense medium. By controlling medium properties, gas velocity, and bed height, the apparent bed density can be adjusted so that low-density particles float and high-density particles sink. In practice, separation density may differ from measured bed density. Large feed particles can cause local defluidization near the upper bed, increasing resistance and effective particle weight. Bubble behavior also affects separation: near minimum fluidization, limited bed activity restricts particle motion, whereas higher gas velocities promote bubble growth, coalescence, and wake-induced upward transport of medium particles. Fine low-density particles may also pass through bubbles, disrupting normal separation. These effects are especially important in high-bed Geldart A systems. This study developed a separation-density model for a Geldart A dense-medium gas–solid fluidized bed from the force balance of spherical particles and compared it with a Geldart B model. Forces on spherical simulated feed particles were measured under different operating conditions, and theoretical separation densities were calculated. Separation tests were then performed to evaluate the effects of gas velocity and bed height, compare bed and separation densities, and assess model reliability. The results support density regulation and scale-up of dry beneficiation using Geldart A media.
Excessive nitrate discharge causes water eutrophication and public health risks, which has become a core challenge in global water environment governance. Conventional nitrogen removal technologies suffer from limitations such as carbon source dependence and secondary pollution, and can hardly meet the requirements of low-carbon water treatment. Driven by electric energy and free of additional chemical reagents, electrocatalytic nitrate reduction enables flexible regulation of product selectivity. Among all possible reaction pathways, selective N2 production is the nitrogen removal route with the highest environmental benefits. However, constrained by the high energy barrier of N–N coupling and intense competition from side reactions, achieving highly selective N2 production remains a major technical difficulty, and most existing reviews in this field focus on ammonia synthesis. This paper systematically reviews the research progress in this field, elucidates the reaction network and nitrogen production mechanism, compares the advantages and disadvantages of three types of selectivity evaluation methods, summarizes the design strategies of multi-scale electrocatalysts, and analyzes how operational parameters (including applied potential, electrolyte composition, pH, etc.) and reactor configuration regulate the reaction selectivity. Finally, the existing challenges are concluded and future development directions are prospected, so as to provide a reference for the research, development and engineering application of electrocatalytic nitrogen removal technology.
Extracellular polymeric substances (EPS) are recoverable high-value biopolymers from excess sludge (ES), but their antioxidant performance and enhancement strategies remain poorly understood. This study systematically investigated sludge-derived EPS (EPSS) and Pseudomonas sp.-derived EPS (EPSP) to elucidate the effects of source, extraction conditions, and sulfation on antioxidant activity. Compositional analysis, physicochemical characterization, Fourier-transform infrared spectroscopy, and excitation-emission matrix fluorescence spectroscopy were used for mechanistic analysis. EPSS exhibited stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity than EPSP, associated with its higher polysaccharide content, lower protein-to-polysaccharide ratio, and more stable polysaccharide–protein heterogeneous network. Extraction conditions significantly influenced EPS yield, particle size, apparent viscosity, and composition; optimal recovery efficiency and antioxidant activity were achieved by centrifugation at 10,000 rpm for 10 min followed by dialysis through a 3500 Da molecular weight cutoff membrane. Sulfation successfully introduced sulfate ester groups while preserving the main structural framework, further enhancing the radical scavenging activities of both EPS types. Notably, EPSS demonstrated greater structural stability during sulfation and retained higher Pb(II) removal capacity compared with EPSP at the tested concentration. Overall, this study provides a mechanistic understanding of factors governing EPS antioxidant performance and validates sulfation as an effective enhancement strategy, supporting the high-value utilization of ES from wastewater treatment plants.
Separation sciences in Türkiye have evolved from early laboratory-based instruction into a robust, multidisciplinary field integral to analytical chemistry. The foundational roots were established before the Ottoman period and were further strengthened with the integration of chemistry into medical, pharmacy, military, and technical curricula. Following the inception of Darülfünun, the first European-style higher education institution and subsequent Republican-era academic reforms, chemistry emerged as an independent discipline supported by specialized institutes and training programs. Collaborative efforts by Turkish and foreign scientists fostered a rigorous laboratory culture, laying the groundwork for modern analytical practices. Since the mid-twentieth century, advanced sample preparation, chromatographic, electrophoretic, and mass spectrometry-based methods have become pivotal across Turkish research centers. Today, these methodologies drive critical applications in environmental monitoring, pharmaceutical and biomedical analysis, food safety, toxicology, forensic science, and industrial quality control. Reflecting this sustained growth and rising international prominence, Türkiye was formally admitted to the Central European Group of Separation Sciences at the 29th International Symposium on Separation Sciences in Belgrade, Serbia, in September 2025. This article provides a comprehensive historical overview of separation sciences in Türkiye, highlighting institutional evolution, major scientific contributors, and the contemporary research directions shaping the field’s future.
Heavy metal wastewater, characterized by high toxicity, poor biodegradability, and strong bioaccumulation potential, poses a serious threat to the ecological environment and human health. Conventional chemical treatment methods are costly and prone to secondary pollution. In contrast, using solid waste to prepare environmental functional materials for “waste control by waste” has emerged as a research hotspot in the field of synergistic water pollution control and resource recovery. This review systematically consolidates the sources, physicochemical properties, and compositional characteristics of typical industrial solid wastes—including red mud, electroplating sludge, fly ash, copper slag, and blast furnace slag—and elucidates how compositional variations constrain the selection of functionalization pathways. On this basis, key preparation techniques, namely hydrothermal synthesis, surface modification/impregnation, thermal treatment, geopolymerization, and sol–gel/polymerization, are critically reviewed and compared in terms of product structural regulation, process complexity, and engineering scale-up potential. Subsequently, the adsorption performance of the resultant materials toward heavy metals such as Pb2+, Cu2+, Cr(VI), As(VI), Cd2+, Ni2+, and Zn2+ is discussed, with particular emphasis on the pronounced effects of pH, temperature, initial concentration, coexisting ions, and adsorbent dosage on adsorption capacity. Notably, Pb2+ exhibits the highest adsorption capacity, whereas the removal of Cr(VI) and As(V) is strongly governed by the positive charge density and reduction efficiency of the material surface. In quinary heavy metal competitive systems, marked differences in the affinity of adsorption sites toward distinct metal ions have been observed. Mechanistic analysis identifies ion exchange, surface complexation, electrostatic attraction, and redox reactions as the predominant removal pathways. This review further incorporates engineering-oriented assessments, including multi-component competitive adsorption, fixed-bed column operation, and regeneration stability, and identifies the critical bottlenecks currently impeding the transition from laboratory-scale research to practical implementation—namely, performance instability arising from feedstock variability, attenuation of adsorption capacity during prolonged operation (with a 10–40% decline over 5–10 cycles), underdeveloped regeneration and recovery routes, and a systemic deficiency in techno-economic analysis and life-cycle assessment data. Finally, future research directions are proposed, emphasizing the development of low-carbon and energy-efficient preparation technologies, the promotion of synergistic valorization of multiple solid wastes alongside critical metal recovery, and the advancement of this field toward engineering applications through artificial intelligence-assisted design and life-cycle assessment, thereby furnishing theoretical references and technical support for the integrated management of industrial solid waste resource utilization and heavy metal wastewater treatment.
After in situ leaching of weathered crust elution-deposited rare earth ore (WREO), large amounts of residual ammonium (RA) salts remain in the ore body and slowly release, causing persistent ammonia-nitrogen pollution in surrounding waters. This study proposes using magnesium chloride for in situ elution remediation of closed mines. Column experiments were conducted to evaluate the effects of eluent concentration, liquid–solid ratio, flow rate, pH, and temperature on residual ammonium removal, and a kinetic model was established based on the shrinking unreacted-core model. The results show that increasing Mg2+ concentration, temperature, or flow rate accelerates the eluting rate, with temperature being the most influential. A higher liquid–solid ratio in the tested range could enhance the elution efficiency of residual ammonium, but it will substantially raise the production cost. Weakly acidic pH 4–6 favors the reaction, while alkaline conditions inhibit it. Kinetic analysis indicates inner particle diffusion control, with an activation energy of 6.03 kJ/mol and a reaction order of 0.3009. Under optimal conditions of 0.1 mol/L Mg2+, 2:1 liquid–solid ratio, 0.6 mL/min, pH 4–6 and room temperature, elution efficiency reaches 95.45%. This work provides theoretical and technical support for green remediation of historical ammonium contamination in WREO.
Capillary electrophoresis (CE) is widely used for DNA fragment analysis, but its separation performance depends strongly on the composition of the polymer sieving matrix, especially in multicapillary systems where matrix operability and reproducibility are critical. Herein, a laboratory-built multicapillary electrophoresis system was used to optimize the sieving matrix for high-throughput DNA fragment separation. The system integrated twelve fused-silica capillaries, high-voltage electrokinetic injection, fluorescence detection, and digital electropherogram acquisition. Using a 100 bp DNA ladder as the model sample, the effects of poly(ethylene oxide) (PEO), Tween 20, and glycerol on electropherogram quality were systematically investigated. PEO concentration was the dominant factor controlling the dynamic sieving network: 0.1% PEO provided insufficient separation, whereas 0.8–1.0% PEO produced clearly resolved DNA peaks. Tween 20 improved peak regularity and electropherogram quality under the tested conditions, with 0.05% providing sufficient improvement without prolonging migration time. Glycerol affected peak distribution by increasing apparent migration resistance in the polymer matrix; however, excessive glycerol slowed DNA migration and markedly extended the separation window. Considering separation quality, matrix operability, and analytical efficiency, 1.0% PEO, 0.05% Tween 20, 2.5% glycerol, 1× SYBR Gold, and 0.5× TBE were selected as the optimized sieving matrix. Under the optimized matrix, inter-capillary migration-time alignment improved the consistency of parallel capillary outputs, with corrected migration-time RSD values generally below 0.5%. The optimized formulation provides a practical basis for high-throughput CE-based DNA fragment analysis.
Low-cost and effective F− removal technology and operational parameters were provided. A novel bimetallic fluoride-removing coagulant (BFrC) was synthesized. Simultaneous removal of fluoride (F−) and turbidity were studied using a new integrated coagulation–adsorption technology based on BFrC (BFrC-“Coagulation-driven adsorption” system (BCS)) in treating low-temperature and low-turbidity waters, in which a “Coagulation-driven adsorption” was the key point. Optimal conditions of the BCS were determined, and Zeta potential and meso- and micro-scopic morphologies were characterized. The results showed BFrC was hydrolyzed and hydroxylated to form positively charged flocs, and BCS reduced residual F− concentration to <1 mg/L. The in situ flocs formed in the BCS (BCS-flocs) gave a very large surface area, providing abundant adsorption sites and channels for F−. Neutral water environment (7.5–8) was conducive to remove F−, while neutral and alkaline conditions are beneficial for turbidity removal. The BCS exhibited strong adaptability to varying water temperatures and turbidity levels. Higher initial turbidity in test waters improved F− removal, while elevated initial F− levels linearly reduced F− removal. Divalent anions (SO42−) inhibited defluoridation more significantly than monovalent anions (Cl− or HCO3−). The BCS-flocs effectively removed F− and turbidity simultaneously, in which F- removal was achieved through adsorption on the flocs, maybe including a combination among initial chemical adsorption, subsequent physical adsorption, and complex composite adsorption, and turbidity removal mainly relied on a multi-mechanism process, including double-layer compression, charge neutralization, and sweep flocculation.
Sludge-conditioning strategies are commonly optimized for filtration performance, with less attention paid to the rheological and textural properties of concentrated sludge and their relevance to low-temperature drying. Here, thermally modified drinking-water sludge (HDWS) was evaluated as a waste-derived mineral conditioner for filtration dewatering and low-temperature drying. The specific resistance to filtration (SRF) was lowest at 30% DS, whereas the 60% DS treatment reduced the moisture content to 35.66% after drying at 60 °C for 30 min, indicating that the optimum filtration condition did not deliver the best drying performance. Increasing the HDWS dosage from 0 to 60% DS reduced the Jenike shear stress from approximately 565 to 490 Pa and the apparent yield stress from approximately 670 to 380 Pa, while also decreasing adhesiveness and cohesiveness. At higher dosages, the sludge retained relatively high small-strain stiffness but exhibited lower nonlinear elastic and viscous resistance. These responses were consistent with weakened macroscopic bonding and altered deformation-dependent energy dissipation after HDWS addition. A possible contribution from mineral-particle contacts is suggested, although the underlying microstructural mechanism was not directly resolved. The 60% DS treatment shortened the time required to reach 20% water content to approximately two-thirds of that for raw sludge but reduced the cake calorific value from approximately 9.6 to 4.3 kJ g−1. HDWS, therefore, exhibited process-specific trade-offs, and its dosage should be selected according to the targeted unit operation and downstream management route rather than regarded as a single overall optimum.
Chromatography started to grow in Greece in the 1980s and it has expanded from basic primary separation methods to a sophisticated, multidisciplinary scientific infrastructure operated today by various expert groups distributed in universities and research institutes located in several cities. Over time, chromatography has become a fundamental scientific field constituting a substantial portion of Greece’s scientific output. Food authentication, environmental analysis and monitoring, biomedical and pharmaceutical research, archeological science, dentistry, veterinary medicine, etc., are, to a great extent, progressing based on advances and applications of chromatographic techniques. The contribution to the scientific field is profound, well established and globally recognized. The proof of this international recognition is reflected in the fact that Greece has been recently accepted in the Central European Group of Separation Sciences after being invited by the Steering Committee of the Group, during the 29th International Symposium on Separation Sciences (ISSS 2025) that took place in Belgrade, Serbia, in September 2025. Herein, a brief historical overview is provided briefly describing the main institutional and group contributors in chromatography all over Greece.
Elaeagnus angustifolia L., belonging to the family Elaeagnaceae and genus Elaeagnus, which is a medicinal and edible homologous material with significant economic and ecological value. Its polysaccharides are one of its key active components, exhibiting bioactivities, including antioxidant, immunomodulatory, antitumor, anti-fatigue, and hypolipidemic effects. This paper reviews the research progress on the extraction, purification, structural features, and bioactivities of E. angustifolia polysaccharides, aiming to provide a theoretical basis and reference for their high-value development and utilization.
Sludge electro-dewatering has emerged as a research hotspot in advanced sludge treatment due to its ability to effectively remove interstitial water that is difficult to separate by mechanical dewatering. This paper systematically reviews the fundamental principles, key influencing factors, evolution of electrode materials, and engineering applications of electro-dewatering technology. Emphasis is placed on analyzing the effects of sludge properties, electric field parameters, and electrochemical reactions on dewatering efficiency. The characteristics and applicable scenarios of three generations of electrode materials—from conventional metal electrodes and carbon-based materials to dimensionally stable anodes (DSA)—are summarized. Current challenges include insufficient electrode stability, the trade-off between energy consumption and efficiency, limited understanding of underlying micro-scale mechanisms, and difficulties in process scale-up. Future efforts should focus on the development of high-performance electrode materials, investigation of multi-field coupling enhancement mechanisms, establishment of machine learning-based intelligent control strategies, and engineering design of continuous electro-dewatering equipment to promote its large-scale application in sludge treatment and disposal.
212Pb is an important medical radionuclide for targeted alpha therapy, and its reliable supply depends on the efficient production of parent nuclides such as 228Ra, 228Th, and 224Ra. Natural thorium resources are abundant and represent a potential source of these radionuclides. However, the separation and enrichment of trace radium from thorium-rich high-salinity systems remain challenging due to extremely low radium concentrations and Th/Ra mass ratios on the order of 109. In this work, a radium separation strategy based on BaSO4 co-precipitation was developed. The precipitation behavior of BaSO4, precipitation kinetics, radium co-precipitation efficiency, and thorium recovery in concentrated thorium nitrate solutions were systematically investigated. The results show that elevated ionic strength and competitive interactions between Th4+ and SO42− reduce the effective sulfate activity under high-thorium conditions, making excess sulfate necessary to achieve efficient BaSO4 precipitation. Under optimized conditions, the radium co-precipitation recovery exceeded 80% at a Ba2+ concentration of 3 mM. Meanwhile, thorium exhibited negligible incorporation into the BaSO4 phase and could be almost completely recovered via subsequent hydroxide precipitation. The proposed method features operational simplicity, use of common reagents, low cost, and compatibility with high-salinity matrices. It provides a feasible technical pathway for the subsequent production of high-purity 228Th or 224Ra and the preparation of 228Th/212Pb or 224Ra/212Pb generator systems.
