Search Results (1,329)

A new approach to 5,5-fused heterocyclic derivatives of cyclopentadienylmanganese tricarbonyl and pentamethylruthenocene is presented. 1,2-Dicarbophenoxycyclopentadienyl complexes of manganese and ruthenium were hydrolyzed to 1,2-dicarboxylic acids. Oxalyl chloride converted the acids to chlorocarbonyls, which reacted with bis(trimethylsilyl)sulfide to give the cyclopentadienyl-fused thioanhydrides. Alternatively, dehydration of the diacids with trifluoroacetic anhydride closed the diacids to cyclopentadienyl-fused anhydrides. Treatment of the anhydrides with p-toluidine followed by oxalyl chloride led to cyclopentadienyl-fused carboxylic imides. This approach enables direct comparison of electron-deficient Mn(CO)₃ and electron-rich Ru(Cp*) coordination environments on the 5,5-fused heterocycles. Spectroscopic data reveal systematic downfield NMR shifts and higher infrared carbonyl stretching frequencies for the manganese complexes, consistent with lower electron density in the Mn(CO)₃ compared to Ru(Cp*). Crystallographic analyses confirm that heterocycle fusion occurs without significant perturbation of the metal–cyclopentadienyl geometry. Comparative analysis across the series demonstrates that metal-dependent effects are primarily electronic rather than structural, with the Mn(CO)₃ and Ru(Cp*) fragments modulating electron distribution within the fused ligand framework. Full article

This study investigates the feasibility of recycling scallop shells as a partial substitute for natural coarse aggregates in concrete at replacement rates of 20%, 30%, and 40% by mass. The originality of the work lies in combining conventional mechanical and durability tests with a six-month environmental monitoring protocol under simulated rainfall and an end-of-life regulatory interpretation of chemical release. Processed shells were used as a 2/20 mm coarse fraction and characterized by a density of 2713 kg/m³, a water absorption of 2.93%, and a Los Angeles coefficient of 15.1. At 28 days, compressive strength decreased from 33.7 MPa for the reference concrete to 27.9 MPa, 28.1 MPa, and 26.7 MPa for SS20, SS30, and SS40, respectively. Water-accessible porosity increased from 7.8% to 9.9%, and carbonation depth after 70 days increased from 6.2 mm to 12.8 mm at 40% shell replacement. In contrast, chloride ion migration decreased from 19.0 × 10⁻¹² m²/s for the reference concrete to 17.4, 16.3, and 12.1 × 10⁻¹² m²/s at 90 days for SS20, SS30, and SS40, respectively. Environmental monitoring showed low runoff concentrations for anions and trace metals, all below the French regulatory thresholds considered in this work. Under the conditions of this study, shell replacement up to 30% appears technically feasible for non-structural or lightly loaded applications, while the environmental behavior remained compatible with an inert end-of-life classification. Full article

Traditional electro-Fenton systems for chlorinated antibiotic wastewater suffer from low mineralization, catalyst deactivation, and secondary pollution caused by chloride ions. In this work, nitrogen-functionalized graphite felt cathodes were synthesized by electrodeposition-pyrolysis. Pyridinic N and graphitic N were identified by XPS. The obtained cathodes were employed in a metal-free electro-Fenton system for effective tetracycline (TC) removal and mineralization. The results show that the optimal electrode (N-GF-3) achieved 93% degradation efficiency and 73% mineralization of TC in 60 min, when the optimized conditions (pH = 3 and current density = 20 mA/cm²) were employed. Unusually, with the presence of Cl⁻, the system showed even higher catalytic performance, having a degradation kinetic constant 2.4 times higher than that without chloride. The electrode was also reusable, maintaining a TC degradation efficiency above 90% in the fifth cycle. Based on fluorescence analysis of ·OH, a possible dual-path reaction mechanism is proposed. This mechanism provides new insights into designing advanced oxidation processes for the treatment of complex chlorinated organic wastewater. Nevertheless, the potential formation of chlorinated byproducts requires additional investigation. Full article

This study investigates the effect of sintering temperature on the hot-corrosion behavior of Ti-6Al-4V alloy in a molten salt environment. Samples were sintered at 800 °C, 900 °C, 1000 °C and 1100 °C, then exposed to the Na₂SO₄—25%NaCl for 300 h at 650 °C. The corrosion kinetics were evaluated by measuring the mass change in the specimens, and the results were correlated with their corresponding corrosion rates. The results show that the sintering temperature drives corrosion kinetics by influencing the sample density and grain size. The sample sintered at 900 °C shows a low corrosion rate due to its refined microstructure. This refined microstructure provides a high grain boundary density, which serves as a diffusion path and enables the formation of a dense, protective Al₂O₃–TiO₂ layer, as confirmed by XPS. In contrast, the sample sintered at 800 °C exhibits high porosity, resulting in an initial weight loss due to molten-salt penetration and evaporation of volatile metal chlorides. The samples sintered at 1000 °C and 1100 °C exhibit coarsened grains, leading to a thicker, brittle oxide layer and severe delamination, which in turn result in high corrosion rates. The results show that optimizing the sintering temperature to around 900 °C would enhance hot-corrosion resistance in salt-contaminated environments. Full article

Next-generation wastewater treatment and recycling rely on membrane-based processes, but they face a trade-off among permeability, selectivity, and fouling resistance. In the present study, thin-film nanocomposite (TFN) membranes were fabricated by incorporating a ternary TiO₂-SiO₂-biochar nanofiller into a polysulfone (PSf) support using nonsolvent-induced phase separation, after which m-phenylenediamine and trimesoyl chloride were used via interfacial polymerization to produce a selective polyamide layer. The membrane compositions were M1 (22 wt.% PSf), M2 (22 wt.% PSf/0.5 wt.% TiO₂/0.5 wt.% SiO₂/0.5 wt.% biochar), and M3 (polyamide-coated M2). FTIR, XRD, SEM, contact-angle, porosity, and mechanical analyses supported successful membrane formation and changes in morphology, wettability, and structural strength after nanofiller incorporation and TFC coating. The addition of a nanofiller increased the hydrophilicity of the membranes by decreasing the water contact angle from 98.6 ± 0.8° for pristine PSf to 35.6 ± 1.5° for the nanocomposite membrane. Consequently, the pure-water permeability increased from 21 to 37 L m⁻² h⁻¹ bar⁻¹. After polyamide layer formation, the optimized TFN membrane maintained a contact angle of 55.4 ± 3.8° and achieved a high Congo red rejection of 98% with permeate flux of 7–9 L m⁻² h⁻¹ bar⁻¹. The membrane also showed good antifouling performance, with flux recovery ratios exceeding 90%. For heavy-metal-containing solutions, the optimized membrane showed apparent removal efficiencies of 78–98% for multivalent heavy metals (Pb²⁺, Hg²⁺, Cd²⁺, Mn²⁺, Zn²⁺, Cu²⁺, Ni²⁺, Fe³⁺, As³⁺, and Cr⁶⁺). Static adsorption tests showed the order M2 > M3 > M1, confirming that exposed TiO₂-SiO₂-biochar sites contribute to pollutant uptake, while the superior filtration performance of M3 is attributed to the combined effect of the polyamide selective layer and adsorption-assisted interactions. Overall, the TiO₂-SiO₂-biochar-based TFN membrane provides a promising platform for dye removal and preliminary heavy-metal attenuation from contaminated water. Full article

The rapid growth of photovoltaic panels installations has led to a dramatic increase in the end-of-life (EoL) panels, creating an urgent need for efficient recycling strategies. In the present study, a pretreatment system consisting of hydrochloric acid was developed to remove impurity metals such as aluminum and iron from EoL PV panel powder prior to the precious metals leaching step. Response surface methodology (RSM) based on a central composite design (CCD) was employed to optimize the effects of main operational parameters, i.e., HCl concentration, leaching time, and solid-to-liquid (S/L) ratio on the dissolution of Al, Fe, Pb, Sn, and Cu. Thermodynamic analysis with the help of HSC Chemistry^® 10 software, confirmed the feasibility of dissolution of the Al, Fe, Pb, Sn, and Cu in chloride media. Experimental results demonstrated that the dissolution rate of Al and Fe under optimal conditions were 86.05 and 91.77 percent, respectively. In all of the tests, copper dissolution remained negligible (<4%), and no silver was detected which confirms the selectivity of the pretreatment. The optimized conditions (1.5 M HCl, 198 min, 20% S/L) enabled effective impurity removal while preserving silver in the solid residue. This study highlights the importance of selective pretreatment in enhancing downstream silver recovery and provides a practical approach for the hydrometallurgical recycling of end-of-life PV waste. Full article

As the use of electronics and mobile devices increases, indium and its related compounds are increasingly prevalent in consumer products. However, the effects of the ionic form of indium on the mammalian renal cells are unclear. Understanding indium toxicity in these cells is important, as it relates to kidney health. Kidneys remove heavy metals, maintain electrolyte balance, and perform other vital functions. This in vitro study examines the effects of indium chloride (InCl₃) on Vero cells, focusing on cell morphology, viability, reactive oxygen species (ROS) production, and expression of key focal adhesion proteins. Cells were incubated in culture media with InCl₃ concentrations ranging from 0 to 3.2 mM for 24 h. Fluorescence confocal microscopy analyses revealed that concentrations above 0.8 mM caused the cells to become more compact and display decreased actin filament lengths, suggesting cellular degeneration, which was further supported by the AlamarBlue^® Cell Viability Reagent. Using a 2′,7′–dichlorofluorescin diacetate (DCFDA/H2DCFDA) assay, we show that ROS levels increase with InCl₃ concentration, accompanied by significant increases in focal adhesion kinase (FAK) and paxillin at InCl₃ concentrations above 0.8 mM. Interestingly, the level of α-actinin detected is not affected by exposure to InCl₃. Our findings demonstrate that InCl₃ has negative impacts on the growth and behaviour of Vero cells at concentrations exceeding 0.8 mM, underscoring the need for further investigation into the biological effects of indium-containing compounds. Full article

In this work, an amide extractant was employed to purify Mo(VI) from chloride media, with particular emphasis on the extraction behavior of impurities and their migration during the extraction and scrubbing stages. The effects of hydrochloric acid concentration, extractant concentration, phase ratio, and temperature on Mo(VI) extraction were examined to clarify the extraction equilibrium and kinetics. Under the optimized conditions, a high extraction efficiency of 93.13% was achieved in a single stage. The loaded organic phase was subsequently purified by hydrochloric acid scrubbing, effectively removing co-extracted impurities while maintaining minimal Mo loss. Efficient stripping of Mo(VI) was realized using an ammonia solution with a stripping efficiency of 98.47%. FT-IR and ESI-MS analyses revealed that Mo(VI) was extracted as a protonated molybdenum oxychloride species interacting with the amide extractant through hydrogen bonding. Density functional theory calculations further confirmed the favorable interaction between the protonated molybdenum species and the carbonyl oxygen of the amide extractant. Thermodynamic analysis indicated that the extraction process was exothermic, with an enthalpy change of −22.17 kJ/mol. These findings provide mechanistic insight into the amide extraction of molybdenum from chloride systems and offer practical guidance for the purification of low-purity molybdenum products. Full article

To elucidate the corrosion behavior of Ti-based metallic glass composites in chloride-containing environments, this study investigates the corrosion resistance of an in situ dendritic Ti₄₈Zr₂₀Nb₁₂Cu₅Be₁₅ metallic glass composite across varying NaCl concentrations and temperatures. The microstructure, surface film composition, and corrosion characteristics were characterized using XRD, SEM, TEM, EDS, XPS, and electrochemical measurements. Results indicate that the alloy consists of a β-Ti(Zr, Nb) dendritic phase embedded in an amorphous matrix. Both increasing NaCl concentration and rising temperature lead to an increase in corrosion current density and a reduction in the capacitive loop radius, signaling a decline in corrosion resistance. The degradation is primarily characterized by localized corrosion and the selective dissolution of the amorphous matrix, which leaves the dendritic phase increasingly prominent. Following polarization, a multi-component oxide film, dominated by TiO₂, ZrO₂, and Nb₂O₅, develops as a protective layer on the alloy surface. However, higher Cl⁻ concentrations and temperatures destabilize this passive film, accelerating matrix dissolution and compromising the material’s overall protective performance. Full article

For the removal of hexavalent chromium [Cr(VI)] from drinking water, a hybrid biosorbent designated chitosan–natural diatomaceous earth (CNDE) was developed and thoroughly characterized. The material couples the ion-exchange and chelating capacity of chitosan—applied at an 85% degree of deacetylation—with the high-surface-area mineral framework of natural diatomaceous earth, onto which the polymer was deposited as a conformal coating. Surface morphology and internal microstructure were examined by scanning and transmission electron microscopy (SEM/TEM), while elemental composition across the hybrid matrix was resolved by energy-dispersive X-ray spectroscopy (EDX). Fourier transform infrared (FTIR) spectroscopy was employed to identify the surface functional groups responsible for chromate binding, and streaming current measurements established the pH of zero charge (pH_pzc), which governs the electrostatic environment at the sorbent–solution interface. Specific surface area was quantified by the Brunauer–Emmett–Teller (BET) method, and the balance of surface acidic and basic sites was determined through titrimetric analysis of total acidity and alkalinity. Thermogravimetric analysis (TGA) was conducted to assess thermal stability. Batch equilibrium isotherm experiments were performed to evaluate Cr(VI) uptake from model drinking water prepared using dilute potassium dichromate solutions adjusted to target pH levels. The effects of solution pH and competing anions (chloride and sulfate) were also investigated. Kinetic studies were conducted to determine the rate of Cr(VI) adsorption, and residual metal concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). Results indicated that CNDE containing 30% chitosan (CNDE30) achieved effective Cr(VI) removal at pH 5. Adsorption was strongly pH-dependent, decreasing as pH increased from 5 to 8. Equilibrium data were well described by both Langmuir and Freundlich isotherm models, while kinetic data followed a pseudo-second-order model. The presence of chloride ions (15 mg/L) reduced adsorption capacity by approximately one-third, whereas sulfate at the same concentration significantly inhibited Cr(VI) removal. Overall, the isotherm results suggest that CNDE30 is a promising material for Cr(VI) removal from drinking water. Its cost-effectiveness, ease of synthesis, and potential for reuse make it particularly attractive for small-scale and decentralized water treatment applications. Full article

Glitter is a distinctive and largely overlooked form of primary microplastic. Unlike more commonly studied microplastics, glitter particles are typically flat, highly reflective, multi-layered, and are composed of polymers such as polyethylene terephthalate, polyvinyl chloride with metallic coatings and a wide range of additives. In response to regulatory restrictions on intentionally added microplastics and increasing consumer demand, “eco-friendly” alternatives based on modified regenerated cellulose, cellulose nanocrystals, or mica have been introduced, although their environmental safety remains insufficiently characterized. This review synthesizes current knowledge on the environmental occurrence and ecotoxicological effects of both conventional and biodegradable glitters. A systematic literature search in Scopus identified 15 peer-reviewed experimental studies meeting predefined inclusion criteria. Evidence spans a wide range of taxa, including bacteria (i.e., Aliivibrio fischeri), microalgae and cyanobacteria (i.e., Phaeodactylum tricornutum, Raphidocelis subcapitata, Microcystis aeruginosa), aquatic plants (i.e., Lemna minor, Egeria densa), marine and freshwater invertebrates as crustaceans (i.e., Daphnia magna), bivalves (i.e., Mytilus galloprovincialis), sea urchins (i.e., Paracentrotus lividus), brine shrimp (Artemia sp.) and terrestrial soil fauna (Eisenia fetida, Folsomia candida). Results indicate that glitter cannot be treated as a uniform stressor: biological responses vary markedly with particle size, shape, colour, polymer type, additive composition, and weathering time, and leachates often exert stronger effects than intact particles. Reported impacts include impaired photosynthesis and growth, oxidative stress, developmental abnormalities, altered energy metabolism, and reduced reproduction. Substantial gaps remain regarding environmental concentrations, ageing processes, mixture effects, and long-term ecological consequences, particularly for biodegradable glitters. Addressing these gaps will require realistic exposure scenarios, mesocosm and field studies, and integrated chemical–biological approaches to support robust risk assessment and safer material design. Full article

The efficient recovery of highly concentrated cadmium (44.55 g/L) from zinc smelting dust leachate is recognized as a significant metallurgical challenge. In this study, we focused on the selective separation of Cd from coexisting arsenic and zinc using trioctylamine (N235) as the extractant. Accordingly, key operational parameters including initial pH, extractant concentration, phase ratio, and temperature were optimized in a systematic manner. Under the optimized conditions of 30% N235, 15% TBP, and 55% sulfonated kerosene by volume, together with an initial pH of 0.5, an organic to aqueous phase ratio of 1 to 1, and a temperature of 20 °C, a three-stage countercurrent extraction process was found to dramatically enhance the Cd extraction efficiency to 99.80% while successfully rejecting As. Subsequently, stripping with 0.7 mol/L aqueous ammonia achieved an 81.4% stripping efficiency in a single stage, and washing with 1.0 mol/L HCl ensured complete regeneration of the organic solvent. Furthermore, Fourier transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectrometry (ESI-MS) analyses corroborate that the extraction proceeds via an anion exchange mechanism. Specifically, within the chloride rich acidic environment, protonated N235 was shown to preferentially coordinate with the tetrachlorocadmate anion CdCl₄²⁻ to form the highly stable and lipophilic complex (R₃NH)₂CdCl₄. Overall, this work provides a scalable technological framework and a robust theoretical foundation for the extraction of highly concentrated heavy metals from complex secondary metallurgical resources. Full article

Heavy metal contamination in water remains a major environmental concern due to the persistence, toxicity, and bioaccumulation potential of metal ions such as Ni²⁺ and Cu²⁺. Therefore, the development of sustainable membrane materials with improved permeability and metal ion retention capacity is of significant interest for advanced water purification applications. In this research, crown ether-functionalized cellulose acetate membranes were developed by employing cyanuric chloride as a linker in order to enable advanced heavy metal ion retention capacity. In order to achieve this, the modification process involved a multi-step approach comprising successive hydroxylation, silanization, triazine activation, and crown ether grafting. The successful functionalization was confirmed by FTIR (Fourier Transform Infrared Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) analyses, while thermal characterization demonstrated improved stability over a wide range of temperatures without compromising the integrity of the cellulose acetate backbone. The crown-ether-functionalized membranes exhibited enhanced performance in terms of heavy metal ion separation, demonstrating significantly higher retention of Ni²⁺ (30%) and Cu²⁺ (27%) as compared to pristine CA membranes (<10%) over repeated filtration cycles. These results demonstrate that crown ether functionalization is a versatile approach for tuning the interfacial features of cellulose acetate membranes in order to achieve increased permeability and selectivity toward heavy metal removal, highlighting their potential for advanced water purification applications. Full article

Lithium-ion batteries have been widely used as energy storage and power batteries due to their unique advantages. However, with increasing demands for battery performance and application scenarios, battery safety has become a significant obstacle to their application. To address this issue, this paper proposes and fabricates an advanced polyimide (PI) separator material with high porosity and excellent thermal stability. By introducing sodium chloride (NaCl) as a pore-forming template into a polyamic acid (PAA) precursor, a PI-based separator with a uniformly interpenetrating sponge-like pore structure was successfully constructed. The obtained PI-NaCl separator exhibits outstanding thermal structural stability, maintaining dimensional integrity without significant thermal shrinkage even when tested at temperatures as high as 250 °C. Furthermore, the porous structure of the PI-NaCl separator demonstrates excellent electrolyte wettability, as the electrolyte rapidly spreads upon contact (contact angle approaching 0°), which is significantly superior to commercial separators. In lithium symmetric cell tests, this separator achieves long-term stable stripping/plating cycling by virtue of its outstanding ionic conductivity, effectively mitigating interfacial side reactions with lithium metal. In LiFePO₄||C full-cell applications, the PI-NaCl-based battery exhibits good rate capability and cycling stability. Additionally, in an open-circuit voltage (OCV) monitoring experiment at a high temperature of 80 °C, the voltage of the PI-NaCl-based battery remained stable continuously for 8 h in comparison to that of the commercial separator-based battery. Full article

Electrochemical water splitting stands as a feasible approach for sustainable hydrogen production, but its industrial implementation is restricted by sluggish oxygen evolution reaction (OER) kinetics and excessive dependence on freshwater resources. As a widely existing alternative, seawater contains a high concentration of chloride ions (Cl⁻), which give rise to serious electrode corrosion and catalyst deactivation, bringing great challenges to actual electrolysis applications. Herein, we report a facile room-temperature two-step soaking strategy to fabricate sulfur-modified NiFe layered double hydroxide (S-NiFe-LDH) catalysts for efficient OER in both alkaline freshwater and seawater electrolytes. The introduction of sulfur not only optimizes the electronic structure of NiFe-LDH to strengthen intrinsic catalytic activity and speed up charge transfer, but also promotes the formation of a Cl⁻-resistant layer, thus significantly improving corrosion resistance. In addition, DFT calculations show sulfur modification in NiFe layered double hydroxide upshifts the O 2p-band center to activate lattice oxygen, switches the oxygen evolution reaction pathway to the lattice oxygen mechanism with reduced thermodynamic barriers, and realizes the selective adsorption of OH⁻ over Cl⁻. As a result, the as-prepared S-NiFe-LDH catalyst exhibits exceptional OER performance, requiring overpotentials (η) of 250, 270, and 290 mV to reach current densities of 50, 100, and 200 mA·cm⁻² in 1 M KOH, respectively, with a Tafel slope of 22.3 mV·dec⁻¹. Moreover, it maintains remarkable stability for more than 200 h in alkaline seawater electrolytes and achieves nearly 100% Faradaic efficiency for water splitting, effectively avoiding the parasitic chlorine evolution reaction (CER). This work provides a scalable and energy-efficient synthetic route for designing advanced non-noble metal catalysts, paving the way for industrial-scale hydrogen production from seawater. Full article