Search Results (894)

Rhodium is a high-value strategic platinum-group metal extensively applied in automotive exhaust purification, fine chemicals, glass production and high-temperature materials. Restricted by uneven primary resource distribution and volatile market prices, recovering rhodium from secondary resources has become increasingly critical. Solvent extraction is regarded as a promising technology for continuous and selective separation of rhodium, yet direct extraction of Rh(III) from chloride media faces severe industrial limitations. These bottlenecks are mainly attributed to diversified chloro-aqua complexes, kinetic inertness of low-spin Rh(III), strong hydration capacity and polynuclear species generation, while solution aging and inconsistent thermodynamic-experimental results further complicate extraction behaviors. This review systematically summarizes recent advances in rhodium solvent extraction from chloride media, correlating aqueous speciation regulation, activation chemistry, extractant molecular structure and extraction-stripping mechanisms. Special emphasis is placed on SnCl₂-, ascorbic acid-, trichloroacetic acid- and malonate-assisted activation systems, as well as amine-, phosphorus-, sulfur-based, synergistic, ionic-liquid and deep-eutectic-solvent extractants. Key factors affecting extraction efficiency, distribution ratio, selectivity and stripping performance are clarified, and current challenges are outlined. Future research should focus on quantitative speciation analysis, in situ mechanistic characterization, targeted extractant design, and integrated evaluation of extraction, stripping, recyclability, cost and real-feed adaptability, so as to provide theoretical support for efficient and clean rhodium recovery. Full article

Grape pomace, the main solid by-product of winemaking, is a promising feedstock for the recovery of trans-resveratrol, a high-value stilbene of increasing interest for food, nutraceutical, and pharmaceutical applications. However, its efficient isolation remains challenging because of matrix complexity, the co-occurrence of structurally related stilbenes and polyphenols, and the chemical instability of trans-resveratrol. This review critically examines recent advances in the recovery of trans-resveratrol from grape pomace, while also incorporating relevant findings from other grapevine-derived matrices to distinguish matrix-specific recovery potential and to place grape pomace within the broader context of grapevine by-product valorization from extraction intensification and selective purification to analytical determination. Various extraction technologies, including ultrasound-, microwave-, and enzyme-assisted extraction, natural deep eutectic solvents, and subcritical water extraction, are assessed alongside conventional solvent extraction with emphasis on yield, selectivity, solvent compatibility, and process feasibility. Downstream separation methods such as liquid–liquid partitioning, solid-phase isolation, adsorbent resins, counter-current chromatography, molecularly imprinted polymers, and foam fractionation are compared in terms of selectivity, enrichment efficiency, solvent demand, and scale-up potential. Although significant progress has been achieved, major challenges remain regarding process integration, solvent sustainability, product stability, and industrial feasibility. Combining mild extraction with selective downstream purification is essential for producing stable, high-purity trans-resveratrol fractions suitable for future use in functional ingredients, natural preservation strategies, and other value-added applications within sustainable food systems. Full article

Fatty alcohols and aliphatic hydrocarbons occur abundantly in nature and serve as critical feedstocks for the surfactant and fuel industries, respectively. However, their industrial-scale separation and purification are significantly hampered by high boiling points and the formation of complex azeotropes. To address these challenges, this study explores a five-column high-vacuum pressure-swing distillation (HVPSD-5C) strategy. Vapor–liquid equilibrium (VLE) analysis of the key components (n-hexanol, n-octanol, n-dodecane, and n-tridecane) validated the thermodynamic viability of the process and established optimal operating conditions. To further enhance efficiency, a heat-pump-integrated configuration (HPI-HVPSD-5C) featuring vapor recompression and heat integration was designed, optimized, and evaluated. Comparison with the baseline HVPSD-5C process demonstrates that the HPI-HVPSD-5C configuration significantly improves sustainability and economics, reducing the total annual cost (TAC) by 17.48%, CO₂ emissions by 16.09%, and energy consumption cost by 12.79%. These findings provide a robust framework for the efficient separation of fatty alcohols from aliphatic hydrocarbons, offering a valuable reference for the purification of other pressure-sensitive azeotropic mixtures. Full article

Replacing artificial dyes with natural pigments in foods, especially carotenoids, has proven to be technologically feasible. This study developed a high-performance pitanga carotenoid extraction process using ionic liquids (ILs) and a factorial design to identify a potential substitute for artificial azo dyes, specifically Allura Red AC and Sunset Yellow FCF. 1-Hexyl-3-methyl-imidazolium chloride [C6mim]Cl was the most efficient IL. The optimized process conditions included a solid–liquid ratio R(S/L) of 1:10 m/m, an IL to ethanol co-solvent ratio R(IL/E) of 1:1 m/m, ultrasound power of 350 W, and six extraction cycles of 7 min each. These conditions yielded a total carotenoid content of 100.40 ± 3.71 μg/g (dry matter), demonstrating effective pigment recovery and a concentration suitable for practical use as a natural colorant alternative to synthetic azo dyes. The reuse of ILs and carotenoid purification were achieved through solid-phase extraction (SPE) using XAD-7HXP adsorbent, resulting in recovery rates of 89.2–76.2% for [C6mim]Cl and 108.9–23.2% for carotenoids. The major carotenoids identified were all-trans-β-cryptoxanthin, all-trans-rubixanthin, and all-trans-lycopene, whose combined presence contributed to a yellowish-orange hue similar to that of Sunset Yellow FCF, as confirmed by CIELAB parameters. Additionally, the [C6mim]Cl carotenoid extract exhibited high antioxidant activity, with an antioxidant capacity of 23.54 µmol of α-tocopherol equivalent. Full article

The flow behavior of montmorillonite (MMT) slurries with a volume fraction of $6.6\times {10}^{-4}$ to $1.6\times {10}^{-3}$, coagulated in 1.0 M NaCl, was investigated across laminar, transitional and turbulent regions using a closed-loop circular pipeline system equipped with dual pressure transducers and a flow meter. In the laminar region, the linearized approximation of the Bingham model was applied to extract yield stress and plastic viscosity, which were subsequently used to estimate friction losses as a function of the Reynolds number. The predicted friction loss calculated using the Hedström number and the Bingham model showed excellent agreement with experimental data. Furthermore, the critical Reynolds number indicating the transition from laminar to turbulent flow was confirmed to increase with increasing yield stress. This trend is qualitatively consistent with flow stability predictions. Notably, the plastic viscosity obtained by this method was significantly lower than values estimated from sediment volume fractions using conventional viscosity correlations based on an effective volume fraction of flocs. These insights into the flow resistance of coagulated clay suspensions are useful for improving the design and operation of water purification, slurry transport, and solid–liquid separation processes. Full article

This study evaluates the non-catalytic thermal pyrolysis of post-consumer polystyrene (PS) in a laboratory-scale batch fixed-bed reactor to recover aromatic-rich liquid products. The PS feedstock was characterized by thermogravimetric analysis (TGA) and micro-Raman spectroscopy to assess its thermal behavior and chemical homogeneity. In addition, the main TGA degradation region was analyzed using Coats–Redfern, Horowitz–Metzger, and Broido kinetic models, yielding apparent activation energies of 269.18, 288.83, and 280.69 kJ mol⁻¹, respectively. Pyrolysis experiments were performed at final temperatures of 400, 450, and 500 °C and heating rates of 10 and 20 °C min⁻¹ under continuous N₂ flow. The maximum liquid yield reached 95.2 wt% at 500 °C and 20 °C min⁻¹, while the estimated gaseous fraction decreased to approximately 2.0 wt%. ANOVA confirmed that final temperature was the dominant factor controlling liquid recovery, contributing approximately 83% of the model variability, whereas heating rate had a secondary but significant effect. GC–MS analysis showed that the pyrolysis oil was mainly composed of aromatic hydrocarbons, including styrene, toluene, and ethylbenzene, with increasing temperature promoting the redistribution of the liquid fraction toward lighter monoaromatic compounds. These results indicate that non-catalytic fixed-bed pyrolysis is a promising route for converting post-consumer PS into aromatic-rich liquid products. However, the recovered oil should be considered a complex mixture rather than a purified monomer stream, and further gas-phase characterization, downstream purification, energy-balance evaluation, life-cycle assessment, and techno-economic analysis are required before definitive claims regarding industrial circularity or environmental performance can be established. Full article

This work presents a novel one-step plasma–solution synthesis of Prussian Blue (PB) and copper hexacyanoferrate (Cu-PBA) nanoparticles via underwater pulsed DC discharge. For the first time, the direct plasma-assisted formation of these coordination polymers is reported. The obtained materials were examined by X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM). These analyses confirmed that the desired phases had formed, along with small amounts of oxide byproducts (α-Fe₂O₃, CuO) arising from the erosion of the electrodes. Photocatalytic activity was evaluated through the degradation of organic dyes (Reactive Red 6C, Rhodamine B, and Methylene Blue) under UV-light irradiation. Both catalysts achieved complete dye degradation within 90 min of UV irradiation (after an initial 30 min dark adsorption step, total experiment time 120 min). Notably, selective performance was observed: PB exhibited higher activity toward the cationic dye Methylene Blue, while Cu-PBA was more effective for the anionic dye Reactive Red 6C. This selectivity is attributed to the specific oxide impurities forming heterojunctions that facilitate charge separation and generate distinct reactive oxygen species. The plasma–liquid method offers a rapid and environmentally benign route to functional PBA-based composites, with potentially scalable characteristics pending further engineering optimization. These findings highlight the potential of utilizing synthesis-induced impurities to tailor photocatalytic selectivity for water purification applications. Full article

Previous studies have demonstrated that C. camphora exhibits diverse bioactivities, but its roots, particularly their phenolic constituents, remain largely unexplored. In this study, we optimized the extraction and purification of total phenolics from C. camphora roots, isolated their chemical constituents, and evaluated their bioactivities. Response surface methodology yielded optimal conditions of 71% ethanol, 78 °C, and a liquid-to-solid ratio of 24:1 (mL/g), giving a total phenolic content of 3.60 mg/g. Purification with HPD-600 resin followed pseudo-second-order kinetics (R² = 0.9987). From the enriched phenolic fraction, twelve phenolic compounds were isolated, seven of which are reported from C. camphora roots for the first time. The enriched fraction exhibited strong antioxidant activities (DPPH IC₅₀ = 107.21 μg/mL; •OH IC₅₀ = 130.7 μg/mL; O₂⁻ IC₅₀ = 141.70 μg/mL) and significant pancreatic lipase inhibitory activity (IC₅₀ = 0.80 mg/mL). This integrated approach expands the chemical diversity of C. camphora roots and highlights their potential as a natural source of antioxidants and lipid-lowering agents. Full article

Radionuclide contamination of surface water bodies poses a significant environmental challenge, particularly for low-productivity dystrophic systems where natural self-purification capacity is limited. This study aimed to assess the potential of phytoplankton and bottom sediments as biogeochemical barriers for radionuclides. Laboratory modeling of ⁹⁰Sr, ²³³U, ²³⁹Pu, and ²⁴¹Am accumulation was conducted using samples of Lake Dryazlo (Tver Oblast) water and bottom sediments as a representative dystrophic model system. Sorption onto phytoplankton biomass over a single growing season was estimated at 1.89 × 10⁴, 5.41 × 10⁴, 6.64 × 10⁴, and 4.04 × 10⁴ Bq g⁻¹ dry biomass for ⁹⁰Sr, ²³³U, ²³⁹Pu, and ²⁴¹Am, respectively. Actinide immobilization in bottom sediments depended on mineral composition and microbial community activity. Ammophos addition increased radionuclide removal from the liquid phase by 2–5-fold through enhanced phytoplankton productivity, and promoted actinide fixation via phosphate mineral phase formation and stimulation of anaerobic sulfur- and iron-cycling bacteria. These results demonstrate a viable biogeochemical barrier approach applicable to the decommissioning of radioactive waste storage ponds and remediation of radionuclide-contaminated water bodies. Full article

We evaluated the antimicrobial and antioxidant capabilities of a bacteriocin purified from a recently identified marine Lactococcus lactis (L. lactis) NAN6399 strain, a lactic acid bacterium recovered from Mediterranean coastal waters near Alexandria, Egypt, and identified by combined API 50 CHL phenotypic profiling and 16S rRNA gene sequencing. Bacteriocin purification was achieved by sequential ammonium sulfate precipitation and reverse-phase high-performance liquid chromatography (RP-HPLC). The purified bioactive fraction had an approximate molecular weight of 20 kDa by SDS-PAGE and a 106-amino-acid N-terminal sequence that, upon BLAST alignment, returned 98.1% overall identity to the Lactococcin 972 family bacteriocin AAK06118.1 from L. lactis IL1403, with divergence confined exclusively to the terminal two C-terminal residues. This sequence is structurally and functionally distinct from canonical Lcn972 (L. lactis IPLA 972): the two peptides share an identical 25-residue signal peptide but diverge entirely in their mature bioactive domains, which exhibit only 9.1% sequence identity. Canonical Lcn972 operates through Lipid II-mediated septum disruption and inhibits only Lactococcus species; the NAN6399 peptide, correctly designated as a novel member of the Lcn972-like peptide family, demonstrated broad-spectrum antimicrobial efficacy against multiple indicator organisms (Staphylococcus aureus, Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterococcus faecalis), producing inhibition zones of up to 30 mm and minimum inhibitory concentration (MIC) values as low as 1.25 μg/mL against S. aureus. Antioxidant capacity was assessed using the DPPH radical scavenging assay, with the purified preparation achieving 73.14 ± 0.34% inhibition. Collectively, these data establish L. lactis NAN6399 as the producer of a bifunctional Lcn972-family bacteriocin with both antimicrobial and antioxidant potential, provide the first experimental characterization of the antimicrobial activity of this Lcn972-family branch, and highlight marine LAB as a productive reservoir for novel bioactive peptide discovery. Full article

Background/Objectives: Understanding the causes of bull subfertility and developing reliable diagnostic tools are critical to reducing economic losses caused by reproductive failure in beef cattle. Metabolomic analysis of sperm from bulls with diverging field fertility may provide insights on sperm metabolism that are associated with fertility. The objective was to determine metabolomic differences in sperm from bulls with differing field fertility. Methods: Angus bulls (n = 15) were classified based on a composite field fertility index (CFI). Frozen–thawed semen straws (n = 10 per bull) underwent a Percoll gradient sperm purification process. Metabolomic analysis was performed through ultra-high performance liquid chromatography coupled high resolution mass spectrometry at the University of Tennessee Biological and Small Molecule Mass Spectrometry Core. The general linear model (GLM) procedure of Statistical Analysis System (SAS) was used to evaluate linear and quadratic relationships between metabolites and CFI. Furthermore, the MIXED procedure was used to determine differences in metabolite abundance between the four highest and lowest fertility bulls. Significance was determined when p ≤ 0.05 and tendency was declared when p ≤ 0.10. Results: A total of 75 metabolites were detected. Quadratic relationships with fertility were observed for kynurenine, xanthine, and ophthalmate. Tricarballylic acid and creatinine showed a negative linear relationship with fertility. When differences in metabolite abundance were assessed between the four highest and lowest fertility bulls, N-acetylglutamate and N-acetylglutamine had greater abundance in low fertility bulls. Conclusions: Metabolites kynurenine, xanthine, ophthalmate, tricarballylic acid, and creatinine are potential fertility markers to identify subfertile bulls from a breeding population. These metabolites have promising future implications in the diagnosis and treatment of beef bull subfertility. Full article

As a finite strategic resource, helium is extracted from natural gas (NG). The concentration of helium in NG is very low, which makes helium hard to separate. The hydrate-based gas separation (HBGS) was proposed as a promising method for the separation of the NG with low helium content in this work. This work systematically investigated the HBGS of helium from simulated NG. The thermodynamic analysis reveals that the existence of 5.00 mol% tetrahydrofuran (THF) in the liquid phase decreased the gas–liquid–hydrate equilibrium pressure by 92.11%, compared to the deionized water system. The single-stage HBGS experimental results show that high THF concentration, low temperature, and high pressure benefited the gas processing capacity and helium purification, but they led to a low helium recovery rate. The best HBGS performance was limited by the “hydrate shell effect”. The decrease in gas–liquid ratio led to an increase in helium concentration without losing the gas processing capacity, but it caused a decrease in the helium recovery rate. Through three-stage HBGS optimization, the helium concentration was increased from 0.54 mol% to 13.54 mol% (a 25.07-fold enrichment), and a total helium recovery of 87.34% was achieved. The mathematical model proposed in this work accurately predicts the performance of HGBS with 2.09% average relative error compared to the experimental data. Full article

A water acetone biphasic extraction system was developed for the separation and purification of erythromycin thiocyanate. Response surface methodology based on a Box-Behnken design was used to evaluate the effects of pH, liquid-to-solid ratio, extraction temperature, and acetone-to-water volume ratio on mass yield. All four variables influenced the extraction performance, and acetone-to-water volume ratio and liquid-to-solid ratio were the most significant factors. Under the optimized conditions of 50.5 °C, pH 9.2, a liquid-to-solid ratio of 3.0 mL/g, and an acetone-to-water volume ratio of 2.5 mL/mL, the mass yield reached 81.58 percent. The predicted and experimental values were in good agreement, confirming the adequacy of the model. The product obtained under the optimized conditions met the relevant requirements of the Chinese Pharmacopoeia. The proposed process is simple and effective, and provides a basis for the purification and scale up of erythromycin thiocyanate and related derivatives. Full article

In this study, new types of eutectic solvents (ESs) are tested for their ability to remove the eight most common bisphenols (BPA, BPB, BPC, BPE, BPF, BPG, BPS, BPAP), which are environmentally monitored substances, from aqueous matrices. A total of 18 ESs based on hydrophobic organic acids, such as capric, caprylic, lauric, and myristic acids, and terpenes, such as DL-menthol, terpineol, linalool, and geraniol, are prepared and mixed in various molar ratios. The highest extraction yield for all types of BPs is achieved with a binary mixture of geraniol:caprylic acid prepared in a molar ratio of 1:1. This ES can be used repeatedly for five consecutive cycles achieving almost 100% recovery for BPB, BPC, BPG, and BPAP, while for BPA, BPE, and BPF, the yield drops to 97% and for BPS to 90%. The efficiency of ES extraction is verified using HPLC-MS/MS to determine the BPs in the aqueous phase. This is performed at a pentafluorophenylpropyl stationary phase with LOQs ranging from 0.24 to 29.1 ng/mL. The applicability of this HPLC-MS/MS method was demonstrated by monitoring the occurrence of BPs in thermal paper and other industrial samples. Full article

Electric discharge cavitation is an effective method for water treatment that combines physical and chemical effects within a single process. It enables water disinfection, extraction acceleration, dispersion of solid particles, and enhancement of porous material permeability. Compared to conventional chemical treatment, it reduces the demand for reagents and minimizes secondary pollution. This new and developing technology significantly contributes to the preservation of natural aquatic ecosystems by providing a sustainable alternative to traditional decontamination methods, thereby reducing the overall anthropogenic pressure on the environment. This study focuses on developing a reliable method for assessing electric discharge cavitation intensity and controlling water purification processes. The proposed approach is based on the oxidation of iodide ions to molecular iodine by reactive species generated during electric discharge cavitation. The adapted iodometric method is sensitive, reproducible, and does not require complex optical or acoustic equipment. Experimental results confirmed that iodometry provides an accurate evaluation of cavitation intensity, allowing control of specific energy consumption and optimization of treatment parameters. Optimal operating conditions were established to control the water processing by electric discharge cavitation: stainless-steel electrodes, specific input energy not exceeding 280 kJ·L⁻¹, the presence of a free liquid surface in the working chamber, and a discharge pulse frequency below 10 Hz. The proposed method supports the development of energy-efficient, low-waste technologies for wastewater and natural water treatment and facilitates the integration of electric discharge systems into existing water treatment infrastructure, particularly under resource-limited conditions. Full article