Search Results (79)

To address the core industrial bottlenecks of conventional batch tannic acid-based germanium precipitation processes—high reagent consumption, long reaction cycles of several hours, severe impurity co-precipitation as well as the common mismatch between single-channel microreactor throughput and industrial production demands. This work combines numerical simulation with experimental validation to investigate microscale two-phase flow regulation, high-throughput microreactor optimization, and tannic acid precipitation intensification. Two-dimensional two-phase flow models are established for straight and zigzag microchannels, with the level set method applied to track interfacial evolution. The regulatory effects of inlet velocity and channel geometry on flow patterns, droplet behavior and mixing performance are clarified. Zigzag channels induce chaotic convection via periodic corners, achieving an order-of-magnitude improvement in mixing efficiency at low Reynolds numbers (Re < 400), which lays a fundamental basis for reaction intensification. Taking zigzag channels as core units, a bidirectional symmetric superposition scale-up strategy is proposed to break the throughput limitation of single-channel systems, and a 3D-printed high-throughput microreactor integrating 78 parallel zigzag channels is designed. 3D simulations reveal a three-stage mixing mechanism and uniform flow distribution among parallel channels, with total throughput two orders of magnitude higher than a single channel. Single-channel experiments with industrial germanium-bearing raffinate yield 91.81% precipitation efficiency under optimal conditions, reducing the reaction residence time from hours in conventional batch processes to the second scale. Staged reagent addition and two-stage serial configuration further raise the efficiency to ~98%, realizing deep germanium recovery with significantly improved reagent utilization and reduced impurity co-precipitation. This process achieves efficient intensification of the chelation precipitation process while balancing throughput and mixing performance, providing a novel and technically feasible approach for efficient low-consumption germanium recovery, and offering solid technical support for the industrial application of microreactors in the hydrometallurgy field. Full article

Ilmenite is the core carrier of titanium resources in China. Conventional flotation systems generally have the problems of insufficient collector adsorption efficiency and limited separation index. Microwave pretreatment can strengthen the flotation process by activating the surface of minerals, but its regulation mechanism on the interface properties of ilmenite and the adsorption behavior of collectors remains to be systematically elucidated. Based on the previous research on the flotation separation effect of the ‘OHA + HDPA composite collector + microwave pretreatment (power of 800 W and irradiation time of 180s)’ system, this paper uses the OHA + HDPA (mass ratio 3:1) composite system as the collector and uses surface tension, contact angle, Zeta potential, infrared spectroscopy and X-ray photoelectron spectroscopy, and other multi-scale complementary characterization methods to systematically study the effect of microwave activation on the wettability of ilmenite surface and the adsorption of collector interface. The results show that the wettability of ilmenite surface by microwaves presents a two-way regulation characteristic. In a pure water system, microwave activation increases the surface polar active sites, the water contact angle decreases from 48.44° to 46.65°, and the hydrophilicity is slightly enhanced. Under the action of the collector, microwaves promoted the directional adsorption and orderly arrangement of reagents, the contact angle of minerals increased to 85.24°, the adhesion work reached 0.560 J/m², and the surface hydrophobicity and solid–gas adhesion ability were significantly improved. Interfacial electrokinetic analysis showed that microwave activation enhanced the positive surface charge of ilmenite, and the isoelectric point shifted from pH 5.1 to alkaline to pH 6.3. In the range of pH 2–10, the Zeta potential of the sample after microwave treatment shifted more negatively, which was due to the synergistic enhancement of electrostatic attraction and chemical chelation sites. Microscopic characterization confirmed that the collector was attached to the surface of ilmenite in the form of chemical adsorption. Microwaves did not change the essential properties of adsorption but increased the adsorption capacity of the collector by 10.9%, and the adsorption layer was more compact and orderly. A mechanism analysis reveals that microwave irradiation induces the oxidation of surface Fe²⁺ to Fe³⁺, and its atomic proportion increases from 23.91% to 38.64%, which significantly enhances the chelation between the collector and the iron site and the stability of the chemical bond. At the same time, combined with the change of XPS coordination environment, it is speculated that microwaves can induce lattice distortion, change the coordination environment of titanium atoms, increase the proportion of Ti-O-Fe bridge oxygen structure, increase the unsaturated titanium active site, and strengthen the coordination between the collector and the titanium site. The synergistic activation of iron–titanium multi-sites together enhances the adsorption strength and adsorption capacity of the collector. This study can provide theoretical support at the interface chemical level for the development of high-efficiency ilmenite flotation process. Full article

Green synthesis of metal oxide nanoparticles is a promising route to reduce toxic reagents and energy consumption while enabling biocompatible nanomaterials for biomedical use. In this work, cerium oxide (CeO₂) nanoparticles were synthesized using lemon juice and sucrose as bio-based chelating, capping and stabilizing agents. Three synthesis routes were designed by varying the use of lemon juice, sucrose, or their combination. The synthesized materials were characterized using thermal analysis (DSC—Differential Scanning Calorimetry and TGA—Thermogravimetric Analysis), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Additionally, their antibacterial activity was assessed against Gram positive bacterium Staphylococcus aureus (S. aureus). Thermal analysis showed that heat treatment at 600 °C promotes high crystallinity, as evidenced by the development of sharp diffraction peaks associated with the cubic fluorite CeO₂ structure, and a dominant F_2g Raman mode at 463 cm⁻¹. SEM micrographs revealed nanometric particles and highlighted that combining lemon juice and sucrose effectively suppresses coalesced structures, yielding more homogeneous morphologies. Crystallite size calculations gave average sizes of 17.2 nm, with the lemon juice-only route producing the largest crystallites. Antibacterial tests revealed a clear dose-dependent inhibition of S. aureus, with marked inhibition of bacterial growth at concentrations ≥5 mg/mL and a plateau effect above 25 mg/mL. This study confirms the feasibility of using plant-based extracts as sustainable reagents for CeO₂ nanoparticle synthesis, with promising structural and biological performance for potential biomedical applications. Full article

To address the challenges of low germanium recovery and high reagent consumption during precipitation from strongly acidic solutions, this study developed a two-stage tannin process intensified by microfluidic mixing and systematically examined the synergistic effects of tannin dosage and pH on coordination chemistry. First-stage recovery rose from 45.23% to 91.28% as the tannin ratio increased from 5- to 15-fold, confirming that sufficient ligand promotes dense chelate formation. Optimising pH to 2.0–2.5 deprotonated tannin hydroxyls, enabling electrostatic–chelation synergy with Ge(OH)₃⁺ and yielding 79.88% recovery—a 20.28% improvement over pH 1.5. The staged second-stage process proved particularly effective: at pH 1.5, a “5-fold primary + 15-fold secondary” scheme achieved 92.04% total recovery with only 13.22-fold cumulative tannin, a 46.81% increase over the single-stage 5-fold treatment; at pH 2.5, a “5-fold + 10-fold” combination reached 95.44% recovery with just 8.67-fold reagent. Microfluidic processing refined particle size and intensified the Ge–O vibration at 864 cm⁻¹, indicating more stable coordination. Economic analysis reveals that efficiency plateaus beyond a 17-fold cumulative dosage, making staged addition the cost-effective choice. By harmonising staged coordination with enhanced mass transfer, this approach resolves the inherent conflict between precipitation depth and reagent overuse, delivering a sustainable strategy for germanium recovery. Full article

A new method has been established for determining trace amounts of platinum in water using ion liquid (IL)-dispersive liquid–liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectroscopy (GFAAS). The method is based on the use of a self-prepared reagent, 5-(5-cyano-2-pyridineazo)-2,4-diaminotoluene (5-CN-PADAT), as a chelating agent, which reacts with Pt(IV) to form a hydrophobic chelate. The extraction solvent is 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈mim][PF₆]), and ethyl acetate is used as the dispersive solvent. After the extraction is completed, the extraction phase formed by [C₈mim][PF₆] and ethyl acetate has a relatively low viscosity and can be directly used for the determination of GFAAS. A single-factor rotational method was employed to optimize conditions affecting DLLME extraction efficiency. The interactions among the factors affecting DLLME were analyzed using response surface optimization (RSM). Under optimal conditions, platinum concentrations exhibited good linearity within the range of 40–280 ng/mL, with a detection limit of 0.3 ng/mL. AGREEprep was used to discuss the ecological friendliness of the method, demonstrating its low cost, ease of operation, simple equipment requirements, and environmental friendliness. When applied to determining trace amounts of platinum in water samples, the results were satisfactory. Full article

The most widely used chelating agent, ethylenediaminetetraacetic acid (EDTA), can cause mild to serious side effects when used for clinical applications. Introducing a polyethylene glycol (PEG) moiety into the molecular structure of EDTA has been shown to lower its toxicity; however, it is unclear whether this could affect EDTA chelation efficiency due to the steric hindrance and the loss of a coordination site caused by the PEGylation reaction. This research aimed to determine if PEGylation could reduce EDTA toxicity without affecting its chelation efficiency. To this end, effective formation constants were determined for EDTA and PEG-EDTA rare earth metal ion complexes using spectrophotometric and titrimetric methods. The stability of PEG-EDTA complexes with the target metal ions was assessed under different conditions using Fourier-transform infrared spectroscopy. The cytotoxicity and metal detoxification capacity of EDTA, PEG-EDTA, and their zinc(II) complexes were determined in two selected human cell types exposed to toxic heavy metal ions. This study suggests that PEG-EDTA has lower toxicity than EDTA, especially when complexed with a nontoxic metal ion, such as zinc(II), while only slightly losing chelation efficiency, potentially making PEG-EDTA a more favourable metal detoxification reagent for clinical applications. Full article

Selective depression of serpentine remains a major challenge in the flotation of low-grade nickel sulphide ores because serpentine slimes impair concentrate grade and recovery. In this study, four structurally related micromolecular depressants bearing amino and phosphonic functionalities were designed, synthesized and systematically evaluated. Micro-flotation screening (depressant range: 0–20 mg·L⁻¹) and bench-scale tests identified an operational optimum near pH 9 and a reagent dosage of ≈18 mg·L⁻¹; potassium butyl xanthate (PBX) was used as a collector and methyl isobutyl carbinol (MIBC) as a frother. Phosphonate-containing molecules (PMIDA and GLY) delivered the largest gains in pentlandite recovery and concentrate selectivity compared with carboxylate analogues and a benchmark depressant. Mechanistic studies (zeta potential, adsorption isotherms, FT-IR, and XPS) indicated that selective adsorption of amino and phosphonate groups on serpentine occurs via coordination with surface Mg sites and by altering the electrical double layer. The DLVO modelling showed that these reagents generate an increased repulsive barrier, mitigating slime coating and entrainment. Contact-angle measurements confirmed selective hydrophilization of serpentine while pentlandite remained hydrophobic. These findings demonstrate that incorporating targeted phosphonate chelation into small-molecule depressants is an effective strategy to control serpentine interference and to enhance flotation performance. Full article

We hypothesized that compounds containing ether linkages within their backbone structures, when exposed to hydroxyl radicals (•OH), can generate ultra-weak photon emission (UPE) as a result of the formation of triplet excited carbonyl species (³R=O*). To evaluate this hypothesis, we investigated the UPE of four compounds, each at a final concentration of 185.2 µmol/L: EGTA (ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid), a potent chelator of divalent cations, and three crown ethers—12-crown-4, 15-crown-5, and 18-crown-6—containing two, four, five, and six ether bonds, respectively. •OH was generated using a modified Fenton reagent—92.6 µmol/L Fe²⁺ and 2.6 mmol/L H₂O₂. The highest UPE was recorded for the Fe²⁺–EGTA–H₂O₂ (2863 ± 158 RLU; relative light units), followed by 18-crown-6, 15-crown-5, and 12-crown-4 (1161 ± 78, 615± 86, and 579 ± 109 RLU, respectively; p < 0.05), corresponding to the number of ether groups present. Controls lacking either H₂O₂ or Fe²⁺ exhibited no significant light emission compared to the buffer medium. These findings support the hypothesis that ether bonds, when oxidatively attacked by •OH, undergo chemical transformations resulting in the formation of ³R=O* species, the decay of which is associated with UPE. In crown ethers exposed to Fe²⁺-H₂O₂, the intensity of UPE was correlated with the number of ether bonds in their structure. Full article

Mass cytometry has promoted the development of single-cell analysis by enabling the highly multiplexed detection of cellular markers using metal-tagged antibodies or cells. Polymer-based mass cytometry reagents have played a critical role in this technique due to their structural versatility, high metal-loading capacity, and sensitivity. This review comprehensively examines the advances in polymer-based reagents for mass cytometry, focusing on their design principles, synthetic strategies, and biomedical applications. We systematically analyze three key categories: metal-chelating polymers with macrocyclic/acyclic chelators developed through controlled polymerization techniques, polymeric particles including encoded microspheres and semiconducting polymer dots, and emerging metal–organic frameworks with high metal-loading capacities. The discussion highlights how these engineered materials overcome spectral limitations of conventional flow cytometry while addressing current challenges in sensitivity, and multiplexing capacity. Finally, we outline current challenges and future research directions for developing polymer probes in single-cell mass cytometry. Full article

N,N,N′-tris(trimethylsilyl)-carboximidamides are effective reagents in synthetic chemistry in reactions with both non-metal and metal halides, because the side product is the mild and volatile ClSi(CH₃)₃ rather than corrosive HCl. The title compound inserts the 2-pyridylamidinate fragment into several non-metal systems, including custom chelating radical ligands. The single-crystal X-ray diffraction structure was determined and modeled by Hirshfeld atom refinement using custom aspherical atomic scattering factors. Excellent data quality led to a model with enhanced precision of all interatomic distances and free refinement of H-atom positions and anisotropic displacement ellipsoids. This structure model is compared to the four previously published analogous structures. Full article

A novel method for the spectrophotometric determination of trace amounts of molybdenum has been developed. This method utilizes a centrifuge-less cloud point extraction (CL-CPE) in a mixed micellar (MM) system containing a nonionic surfactant (Triton X-114) and an ionic liquid (Aliquat^® 336, A336). The chromophore chelating reagent employed was 4-nitrocatechol (4NC, H₂L). This work marks its first application as a CPE reagent. Under the optimal conditions, Mo(VI) forms a yellow ternary complex with 4NC and A336, which can be represented by the formula (A336⁺)₂[MoO₂L₂]. The method possesses the following characteristics: limit of detection (LOD) of 3.2 ng mL⁻¹, linear range of 10.8–580 ng/mL, absorption maximum of 435 nm, molar absorptivity coefficient of 3.34 × 10⁵ L mol⁻¹ cm⁻¹, and Sandell’s sensitivity of 0.29 ng cm⁻². The method has been successfully employed for the determination of molybdenum in reference standard steel samples, bottled mineral water, and a molybdenum-containing dietary supplement. Full article

Chalcopyrite and molybdenite are vital strategic metal resources. Due to their close association in ores, flotation methods are commonly used for separation. The flotation separation method primarily employs the “copper depression and molybdenum flotation” process, enhancing the wettability difference between chalcopyrite and molybdenite through a chalcopyrite depressant. Traditional depressants often face challenges, including low selectivity, high dosage requirements, poor stability, and significant environmental pollution, highlighting the need for new, highly selective green reagents. This study introduces the novel chalcopyrite depressant 2-mercapto-6-methylpyrimidin-4-ol (MMO) for flotation separation. The influence of MMO on chalcopyrite and molybdenite flotation recovery was examined through microflotation experiments. Additionally, the effects of MMO and ethyl xanthate on surface wettability were assessed via contact angle measurements. The adsorption microstructure and interaction mechanism of MMO on chalcopyrite were elucidated using FT-IR, TOF-SIMS, and XPS analyses and DFT simulations. Results indicate that MMO enhances chalcopyrite hydrophilicity and exhibits a strong depressing effect on its flotation, while minimally impacting molybdenite recovery. Thus, it serves as an effective depressant. During adsorption, N and S atoms in MMO donate electrons to Fe and Cu ions, leading to triple bond adsorption and a stable chelate structure. These findings are crucial for achieving a greener and more efficient flotation separation of copper and molybdenum. Full article

A single (Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃ phase material with a tetragonal structure is processed and synthesized with a modified Pechini method using ethylenediaminetetraacetic acid and glycerol as chelating and esterifying agents, respectively. The complete chemical transformation to the desired phase is achieved at 900 °C, which is 300 °C lower than conventional synthesis methods. Its consolidation, reaching up to 91% relative density, is carried out at 1400 °C. It is clearly demonstrated that the use of ethylenediaminetetraacetic acid and glycerol reagents is particularly beneficial for inducing a homogeneous grain size distribution (10 μm), which leads to very promising electromechanical properties (d₃₃ = 451 pC/N; d₃₁ = 160 pC/N; kp = 0.40; $\epsilon {\prime }_{33}^T$ = 4790 and Q_m = 358) of the densified system. Full article

The success of multiple nuclear medicine radiotherapeutics in treating cancer requires an increased supply of companion diagnostic imaging agents radiolabeled with gallium-68. Cyclotron production addresses the need for access to gallium-68 and has been validated for use with commercially produced sterile kits. For novel research tracers undergoing translational studies (IND or RDRC), developing and purchasing sterile kits is time- and cost-prohibitive. An on-cassette labeling method with terminal filtration allows non-sterile kits to be fabricated in-house, simplifying workflow and allowing multiple PET imaging agents to be evaluated using the same kit (i.e., parts, reagents, and timelist) with minimal variation. Using modified GE gallium chloride cassettes, four diverse clinically relevant tracers (DOTA-TOC, FAPI-04, pentixafor, and PSMA-11) were radiolabeled with gallium-68 to evaluate the approach using DOTA and HBED-CC chelator types. The tracers were all formulated according to established FDA-approved formulations and sterile-filtered using a PVDF membrane. The automated procedure is robust, tolerating DOTA and HBED-CC chelators, and can be used to screen numerous gallium-68 agents for rapid translation to clinical use. Full article

Anticoagulants can complicate the interpretation of routine and specialised coagulation assays. Several methodologies have been developed to minimise or eliminate anticoagulant-associated interferences; however, no ‘universal methodology’ that encompasses different anticoagulant classes is currently available. Ciraparantag is a promising reversal agent that can bind both direct oral anticoagulants (DOACs) and heparin-like anticoagulants. As such, we aimed to investigate whether ciraparantag could be employed as a ‘universal’ anticoagulant chelator in vitro. Human plasma was spiked with ascending concentrations of ciraparantag, with or without DOACs or heparin, and assayed for routine coagulation parameters. Ciraparantag had minimal effects on coagulation testing when added to human plasma at concentrations similar to pharmacokinetic maxima; however, ciraparantag did not remove DOAC- or heparin-associated activities in vitro, which was likely due to the preferential chelation of anionic substances in the coagulation reagents. In contrast, DOAC-Stop™, a commercial activated charcoal-based adsorbent, efficiently removed both DOAC- and ciraparantag-associated interferences. In conclusion, although ciraparantag is not effective as a ‘universal’ anticoagulant chelator in vitro, we report that activated charcoal-based adsorbents may be clinically useful in situations where laboratory investigations are complicated by the presence of DOACs and/or ciraparantag. Full article