Search Results (3,067)

Reaching the end of their lifecycle, lithium-ion batteries contain significant amounts of lithium residues as well as valuable metals such as Co, Ni, and Mn, presenting both environmental risks and opportunities for resource recovery. Recent advances in hydrometallurgical, pyrometallurgical, and biotechnological methods enable the recovery of high-purity lithium compounds while also increasing their economic viability. This study analyzes the contribution of lithium recovery methods to sustainability criteria, their annual averages, and total data between 2008 and 2026, considering the number of academic references in the literature. The analysis compares the contributions of recycling methods to lithium and other metal recovery efficiency, process efficiency, energy consumption, environmental impact, economic impact, adaptation to technological developments, and integrated applications. LIB recycling methods showed higher overall and annual average sustainability contributions to the recovery efficiency of other metals and lithium compared to other criteria. Their contributions to process efficiency and the environment were also relatively high. However, their contributions to the economy, adaptation to technological developments, and integration of methods remain low. Furthermore, since the contribution to energy consumption is negative overall, further academic studies are needed to improve contributions, particularly in energy consumption and the other three criteria mentioned above. Full article

The transport of metal ions from highly saline matrices remains challenging due to the elevated ionic strength and complex chemical speciation that characterize seawater and desalination brines. In this work, the influence of membrane composition on Cd(II) transport through polymer inclusion membranes (PIMs) was evaluated using cellulose triacetate (CTA), poly(vinyl chloride) (PVC), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membranes containing Aliquat 336. Membranes were tested using model NaCl solutions, seawater, and desalination brine, and the effects of membrane mass, polymer matrix, carrier/plasticizer composition, and receiving phase were investigated. Reducing the CTA membrane mass by 50% did not significantly affect transport efficiency, indicating that membrane composition had a greater influence on Cd(II) transport than membrane mass under the conditions evaluated. Among the evaluated formulations, the optimum PVDF-HFP membrane contained 60 wt.% PVDF-HFP, 30 wt.% Aliquat 336, and 10 wt.% butyl stearate (BTS), achieving a transport efficiency of 95.5% and an initial flux of 2.7 × 10⁻⁶ mol m⁻² s⁻¹ in desalination brine. The use of 0.5 M HNO₃ as the receiving phase markedly improved Cd(II) transport in both synthetic saline solutions and real seawater and desalination brine compared with ultrapure water. These results highlight the importance of polymer–plasticizer interactions in controlling Cd(II) transport and demonstrate the potential of PVDF-HFP/Aliquat 336/BTS membranes for metal recovery from complex saline media. Full article

Reliable visual identification of household gas facilities is important for safety inspection, yet images acquired in real indoor environments are frequently affected by cluttered textures, shadows, metallic reflections, stains, dust, motion blur, occlusion, and viewpoint variation. In RT-DETR, these conditions can weaken cross-scale structural cues, reduce the ranking of small-object candidates, and amplify localization errors under strict IoU criteria. We hypothesize that coordinated intervention at feature fusion, query allocation, and box regression can alleviate this coupled failure process without enlarging the decoder-query budget. Accordingly, DRQ-RTDETR integrates degradation-aware detail recovery, small-object-guided query selection, and scale-adaptive geometric refinement. Experiments on a real household gas facility dataset containing 21,813 images and 47,169 instances across eight safety-related categories show that DRQ-RTDETR improves mAP from 0.6168 to 0.6576, mAP50 from 0.7909 to 0.8124, mAP75 from 0.6702 to 0.7136, and mAPsmall from 0.4639 to 0.5247 relative to RT-DETR. The larger gains in mAPsmall and mAP75 indicate that the proposed coordination is particularly effective for weak-response compact components and boundary-sensitive localization in degraded household scenes. Full article

This study presents a novel, low-temperature thermochemical activation process for the selective extraction of Cr and V from carbon steel EAF (CH1) and FeCr (CH2) slags at temperatures of up to 600 °C. Of the twelve reagents tested, NaOH was identified as the optimal alkaline agent for Cr activation at 500 °C, achieving extraction yields of 61.6% for CH1 (slag-to-reagent ratio of 12:8 g) and 80.6% for CH2 (ratio of 12:16 g). KOH at 400 °C was the most effective reagent for V extraction, yielding 89.4% for CH1 and 54.5% for CH2. Maximum metal concentrations were achieved after only five minutes of leaching at 60 °C. The process exhibits high selectivity; primary matrix components (Fe, Si, Al, Ca, Mg) either do not leach or only leach in negligible amounts. Iron forms insoluble oxides, and calcium converts into stable calcite, while magnesium is bound in the form of hydrotalcite specifically in the CH2 slag leaching residue. The CaCO₃ content was proven to be a crucial parameter determining the activation efficiency and effective transformation of Fe-Cr-V phases. This procedure enables the recovery of clean Cr and V leachates, while the residual mineral-rich fraction offers potential for various industrial applications in a closed-loop slag recycling process. Full article

Industrial effluents containing zinc, cadmium, and nickel represent both an environmental challenge and a valuable secondary resource. This study investigates the simultaneous recovery of Zn(II), Cd(II), and Ni(II) from nitric acid solutions using di-(2-ethylhexyl) phosphoric acid (D2EHPA) dissolved in commercial diesel fuel in a continuous counter-current semi-pilot mixer–settler extraction system. The effects of key operating parameters, including aqueous-phase pH, initial metal concentration, phase ratio, contact time, stirring speed, and stripping agent, were systematically evaluated. Metal concentrations were determined by atomic absorption spectrometry, while Fourier-transform infrared spectroscopy was employed to investigate the extraction mechanism. The optimum operating conditions were pH 2.45 for Zn(II) and pH 5.38 for Cd(II) and Ni(II), a phase ratio of V_A/V_O = 1.5/3.5, and a stirring speed of 700 rpm. Under these conditions, high extraction efficiencies were achieved, with Zn(II), Cd(II), and Ni(II) recoveries of 98.52%, 76.86%, and 84.04%, respectively. FTIR characterization, together with slope analysis, suggested a dimeric cation-exchange extraction mechanism involving D2EHPA species in the organic phase. Among the stripping agents evaluated under the present experimental conditions, 0.5 M H₂SO₄ produced the highest stripping efficiencies for Zn(II), Cd(II), and Ni(II). Although the stripping efficiencies remained moderate, particularly for Cd(II) and Ni(II), these results demonstrate the relative effectiveness of H₂SO₄ compared with the other stripping agents examined. Further optimization of the stripping conditions is expected to improve metal recovery. The proposed process shows significant potential for industrial wastewater treatment, metal recovery, and resource valorization. Full article

The rapid increase in electric vehicles has increased the generation of spent lithium-ion batteries (LIBs) and the need for efficient lithium recovery technologies. This study compared two distinct sulfation roasting routes, using sodium sulfate (Na₂SO₄) at 750 °C and sulfuric acid (H₂SO₄) at 550 °C, applied to black mass derived from lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NCM) batteries. Metal extraction efficiencies were determined by inductively coupled plasma optical emission spectrometry, while reaction products were identified by X-ray diffraction analysis. Sulfation roasting using Na₂SO₄ resulted in low lithium recovery for both materials, with maximum extractions of 5.7% for LFP and 24.5% for NCM. In contrast, H₂SO₄-assisted roasting achieved high lithium recovery from NCM black mass, reaching 90.8%, 91.5%, and 88.5% at 45, 90, and 180 min at 550 °C, respectively, with lithium predominantly converted into water-soluble lithium sulfate. Lithium extraction from LFP black mass remained below 13% under all conditions. Statistical analysis confirmed that lithium recovery at 45 min was equivalent to longer residence times, while prolonged roasting increased manganese coextraction and altered cobalt and nickel behavior. Overall, sulfuric acid-assisted sulfation roasting is an efficient and energy-favorable route for lithium recovery from NCM black mass, whereas sulfation roasting is unsuitable for LFP materials, under the tested conditions. The results highlight the importance of cathode chemistry segregation and demonstrate the feasibility of reducing processing time without compromising lithium recovery. Full article

A simple and cost-effective graphite paste electrode modified with 5-(4-aminophenyl)-4-amino-1,2,4-triazole-3(2H)-thione was developed for the selective voltammetric determination of Cu(II) ions in environmental water samples. The N,S-donor ligand was incorporated into a graphite–polystyrene matrix without the use of nanomaterials, providing a reproducible and straightforward electrode fabrication route. Scanning electron microscopy revealed a rough, porous surface morphology with an enhanced electroactive surface area of 0.065 cm², approximately twice the geometric area. Electrochemical impedance spectroscopy confirmed diffusion-controlled mass transport, while cyclic voltammetry indicated quasi-reversible behaviour of the Cu(II)/Cu(0) redox system with a linear dependence of peak current on the square root of the scan rate. Differential pulse voltammetry under optimised conditions (0.1 mol·L⁻¹ H₂SO₄, pH 1.0–1.2) yielded a linear analytical response over the concentration range of 0.01–0.4 μmol·L⁻¹ (R² = 0.99507), with a limit of detection of 0.02 μmol·L⁻¹ and a limit of quantification of 0.06 μmol·L⁻¹—well below the WHO guideline for copper in drinking water. The sensing mechanism involves selective N,S-bidentate coordination of Cu(II) at the electrode surface, followed by electrochemical reduction, as supported by FT-IR spectroscopic evidence. The sensor demonstrated good selectivity toward Cu(II) in the presence of common interfering metal ions at up to 20-fold excess. The method was successfully validated against ICP-OES (recovery 99.8%, RSD < 0.33%) and confirmed by spike–recovery experiments (99.0–99.5%), confirming its practical applicability for trace-level environmental monitoring. The modified electrode retained approximately 93% of its initial response after 30 consecutive measurements and 91% after 14 days of storage, demonstrating good operational stability. Full article

Exhaust gas temperature is a critical indicator of combustion efficiency and waste heat recovery in regenerative aluminum smelting furnaces, directly governing the energy intensity and carbon footprint of secondary aluminum production—a cornerstone of the circular economy. However, accurate prediction is challenged by pronounced long-range thermal lag and dynamically evolving spatial dependencies among process variables during operational transitions, which hinder real-time process optimization for energy savings. To address these challenges and advance sustainable manufacturing, a novel prediction model termed ChronoClassGAT (Chronological Class-aware Graph Attention Network) is proposed in this paper. The model integrates three key components: (1) a Temporal Convolutional Autoencoder (TCN-AE) with a Gaussian Mixture Model (GMM) for unsupervised identification of distinct operating regimes, providing categorical priors for dynamic graph construction; (2) a multi-graph fusion mechanism that builds operating-condition-specific spatial structures, enabling a Graph Attention Network (GAT) to adaptively model evolving inter-variable dependencies; and (3) a ChronoSwish activation function that modulates LSTM-based temporal encoding with time-aware periodic and switching signals, enhancing responsiveness to transient dynamics. Validated on real-world industrial datasets, ChronoClassGAT achieves superior prediction accuracy (RMSE of 2.2712, MAE of 1.8023, and $R^2$ of 0.9985) over state-of-the-art baselines. By enabling precise and robust exhaust gas temperature forecasting, our framework provides the decision-support intelligence needed for optimizing regenerator switching, minimizing thermal losses, and reducing fuel consumption, thereby contributing significantly to the operational energy efficiency and environmental sustainability of the energy-intensive non-ferrous metal industry. Full article

To control the impact of the invasive crayfish Faxonius limosus on native crayfish and fish biodiversity in the Danube River ecosystem, one possible approach is the valorization of this species through the production of value-added biopolymers, considering the continuously increasing demand for chitosan. However, there are very limited data regarding the utilization of Faxonius limosus shell waste as a source of chitosan. Therefore, this study evaluated chitosan recovery from spiny-cheek crayfish shell, including conventional chemical treatment with different demineralization intensities and numbers of deproteinization steps, as well as ultrasound and autolysis-assisted deproteinization. The obtained chitosans were characterized in terms of yield, moisture content, degree of deacetylation, color, crystallinity and structural properties. Residual heavy metal concentrations (Hg, Cd and Pb) were determined to assess the safety of crayfish shell as a raw material intended for food-related applications. Particular emphasis was placed on gel-related functional properties of obtained chitosans, including rheological behavior, wettability on fruit surfaces, antioxidant and antimicrobial activities, and film-forming ability. These properties govern the formation of structured biopolymeric networks and their performance as active food coating materials. The relationships between the extraction process, physicochemical characteristics and functional performance were investigated to identify the most suitable chitosan for potential food preservation applications. The results demonstrated that extraction conditions significantly affected the physicochemical and functional properties of chitosan. Samples obtained through intensive deproteinization showed enhanced antimicrobial activity, whereas higher antioxidant activity was observed in samples containing residual bioactive compounds. Most formulations exhibited suitable wettability on apple and nectarine surfaces and successfully formed transparent films, indicating their potential application as edible coatings. Full article

With the rapid development of DC grids, resonant DC circuit breakers (RDCBs) have become critical for fault isolation. However, existing RDCBs often suffer from severe energy mismatches, and components, including mechanical switches, resonant capacitors, and power electronic devices, suffer from excessive internal overvoltage during the current interruption process. To address these issues, a novel RDCB with a capacitor self-charging current excitation source (CES) is proposed in this paper. First, by controlling the charging process of CES by the fault current, the injected energy is matched with the commutation requirements, significantly reducing the transient recovery voltage (TRV) applied to the mechanical switch. Second, to suppress the voltage applied to the resonant capacitor, a metal oxide arrestor (MOA) should be connected directly in parallel with the resonant capacitor, avoiding overvoltage caused by the internal oscillation between the resonant inductance and the resonant capacitor. Furthermore, an anti-parallel magnetic core is designed for CES, ensuring dynamic current sharing among parallel IGBTs while maintaining a zero-inductance characteristic externally. Simulation results verify that the proposed RDCB reduces the peak TRV by at least 64% compared with existing RDCBs. Furthermore, the effectiveness of the proposed overvoltage suppression methods is validated, significantly improving the interrupting reliability. Full article

The development of reusable nanomaterials for the extraction of trace-metals from complex matrices remains challenging because strong metal-chelating functionalities often hinder desorption and regeneration, whereas weaker binding sites compromise selectivity and enrichment efficiency. This limitation has been addressed by designing a ligand-engineered fibrous mesoporous silica nanomaterial (Van-KCC-1) via the integration of the unique structural features of KCC-1 with an o-vanillin-derived Schiff-base chelator. The material was synthesized throughout the chemical grafting of 3-aminopropyltriethoxysilane (APTES) onto fibrous mesoporous silica KCC-1, followed by condensation with 3-methoxy-2-hydroxybenzaldehyde (o-vanillin). The successfulness of functionalization and Schiff-base formation were confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The radially oriented fibrous channels of KCC-1 provide a highly accessible surface that remains available for interaction with the targeted ions even after chemical modification. This architecture facilitates rapid mass transfer and efficient utilization of binding sites, while the incorporated Schiff-base ligand introduces imine, phenolic, and methoxy donor groups capable of selectively and reversibly coordinating Ni(II) and Cd(II). The resulting balance between adsorption strength and desorption efficiency enables both effective metal capture and sorbent reusability. More importantly, the study demonstrates how KCC-1 can serve as a versatile nanosilica scaffold for the incorporation of tailored chelating ligands without sacrificing structural accessibility. The functionalized nanomaterial was evaluated as a dispersive solid-phase extraction (DSPE) sorbent coupled with inductively coupled plasma optical emission spectrometry (ICP-OES). Under optimized conditions, linear ranges of 0.035–50 μg L⁻¹ for Ni(II) and 0.058–50 μg L⁻¹ for Cd(II) were obtained, with limits of detection of 0.011 and 0.019 μg L⁻¹, respectively. The method exhibited excellent precision (relative standard deviation ≤ 3.6%) and recoveries of 92.00–98.83% in certified reference materaisl (NIST CRM 1643d), mineral water, tap water and synthetic wastewater. In addition, the nanochelator has retained more than 87% of its initial sorption efficiency after six adsorption–desorption cycles and showed minimal interference from common coexisting ions. These findings establish Van-KCC-1 as an efficient, selective, and reusable DSPE sorbent in the determination of trace-metals while highlighting the broader potential of fibrous mesoporous silica KCC-1 as a platform for the rational design of next-generation chelated nanomaterials. Full article

This critical perspective review first classifies glyphosate-sensing platforms and then evaluates their analytical applicability to agricultural runoff. Platforms are divided at the primary level into optical and electrochemical transduction, because these families measure different physical signals and have different sources of matrix interference. They are then grouped by the process that produces selectivity or signal change: direct interaction or metal coordination, affinity recognition by aptamers, antibodies, or molecularly imprinted polymers, catalytic modulation by enzymes or nanozymes, and separation or preconcentration before detection. This hierarchy distinguishes recognition chemistry from transduction method and device configuration. The review next defines four intended analytical applications—trace surveillance, runoff event screening, spill triage, and laboratory-adjacent confirmation—and compares them in terms of matrix, target concentration range, sample preparation, reporting metrics, and quality control requirements. Glyphosate occurs in dissolved and particle-associated forms, degrades mainly to AMPA, and coexists with phosphate, glufosinate, divalent cations, natural organic matter, and suspended sediment. Consequently, the lowest reported LOD is rarely the sole criterion for selecting a method. Matrix-matched calibration, spike recovery, selectivity, response time, storage stability, reader requirements, and invalid result rules determine whether an assay is suitable for a specified analytical application. The most defensible near-term approach combines matrix-specific sample preparation, platform-specific controls, and LC-MS/MS confirmation when results are regulatory, contested, or close to a decision threshold. Full article

Efficient component separation is a prerequisite for high-value recycling of blended textile waste. Herein, a two-stage metal-free recycling process for wool/polyamide 6 (PA6) carpet waste is developed, combining mild acid-assisted selective separation with monomer-level PA6 regeneration. Acetic acid pretreatment at 80 °C removes surface dyes, followed by formic acid treatment for selective PA6 dissolution. Both acids are efficiently recyclable via low-temperature rotary evaporation, with an average PA6 recovery yield over 75% across five consecutive cycles. Recovered wool preserves its original scale structure and tensile strength comparable to virgin fibers, and reclaimed PA6 maintains its macromolecular and crystalline structure, verifying the mildness of the separation protocol. The recovered PA6 is further depolymerized via a microwave-assisted acetic anhydride/organobase system, where the phosphazene base ^tBuP₄ achieves a maximum N-acetyl-ε-caprolactam yield of 74.6%. Depolymerization efficiency is governed by catalyst basicity, nucleophilicity, and acetic anhydride-mediated polyamide backbone activation. After deacetylation, the resulting ε-caprolactam is repolymerized with the same ^tBuP₄ catalyst, producing regenerated PA6 with chemical structure and thermal properties nearly identical to virgin PA6. Full article

The depletion of high-grade manganese ore reserves, accompanied by the progressive decline in ore quality, has intensified concerns regarding the supply of suitable manganese raw materials for Kazakhstan’s ferroalloy industry. Under these conditions, the development of efficient processing technologies for iron manganese ores characterized by low Mn/Fe ratios and complex mineralogical compositions has become increasingly important. This review examines current pyrometallurgical approaches for the processing of iron manganese ores, including carbothermic reduction roasting followed by magnetic separation, reduction smelting for the production of rich manganese slag, and hydrogen-based selective reduction followed by magnetic separation. Particular attention is given to the mineralogical and chemical characteristics of Kazakhstan’s iron manganese ores, which significantly limit their direct utilization in conventional ferromanganese production processes. The advantages and limitations of these technologies are critically evaluated in terms of metal recovery, Mn/Fe upgrading efficiency, energy requirements, environmental performance, and industrial applicability. The comparative analysis identifies reduction smelting as the most suitable route for Kazakhstan’s iron manganese ores under current technological conditions. This conclusion is primarily supported by the low Mn/Fe ratios, elevated iron contents, and complex mineralogical associations characteristic of the major Kazakhstan deposits, which limit the efficiency of solid-state reduction followed by magnetic separation. During smelting, the original mineral structure is destroyed, and iron and manganese are separated directly between the liquid metal and slag phases. Published studies report iron recoveries exceeding 95%, MnO recovery to the slag of approximately 94.6%, and Mn/Fe ratios above 15 in the resulting rich manganese slag. In addition, the process produces two potentially marketable products-cast iron and rich manganese slag-and can be integrated more readily into Kazakhstan’s existing ferroalloy production infrastructure. Therefore, reduction smelting currently represents the most technologically mature and practically feasible route for the comprehensive utilization of Kazakhstan’s iron manganese resources. Full article

Automotive paint sludge (APS) is a hazardous industrial waste generated during automotive coating operations and is characterized by high moisture content, variable organic and inorganic composition, volatile organic compounds, pigments and heavy metals. Conventional disposal methods, including landfilling and direct incineration, present increasing environmental and regulatory challenges, thereby motivating interest in thermochemical conversion technologies for APS valorization and energy recovery. This review evaluates the current state of research on APS thermochemical conversion through incineration, pyrolysis and gasification pathways. The review compares the major operational characteristics of thermochemical pathways, including reactor conditions, temperature ranges, product yields, energy recovery potential, pollutant formation and downstream cleanup requirements. Also, techno-economic considerations such as drying energy demand and scale-up limitations are discussed. According to the current literature, incineration is the most industrially mature route for APS destruction, whereas pyrolysis offers more flexibility for fuel and material recovery. Gasification shows potential for syngas and hydrogen production but remains insufficiently studied for APS applications. Despite growing interest in APS valorization, a lot of research gaps remain regarding standardized feedstock classification, pilot-scale validation, process integration, environmental risk assessment and techno-economic optimization. Conclusively, future approaches towards managing APS would need to incorporate process optimization for specific APS types, incorporation of co-processing techniques, as well as an overall assessment for both environmental and economic feasibility. Full article