Polyacrylamide (PAM) in environmental water has become a major problem in water pollution management due to its high molecular mass, high viscosity and non-absorption by soil. CoFe2O4 with strong magnetic properties was prepared by solvent-thermal synthesis method and used as the catalyst for the removal on PAM in heterogeneous Electro-Fenton (EF) system. It showed that the removal efficiency of PAM by the heterogeneous EF system using CoFe2O4 catalyst was 92.01% at pH 3 after 120 min. Further studies indicated that ·OH was the most significant active species for the removal of PAM, and the contribution of ·O2- and SO4·- for the removal of PAM was less than 15%. The reusability test and XRD, XPS, FTIR analyses proved that the catalyst had good stability. After a repeated use for five times, the catalyst still had a high PAM removal rate and stable structure. The valence distribution and functional groups of the phase components of the catalyst did not change significantly before and after the reaction. The possible mechanism of catalyst activation of H2O2 was deduced by mechanism investigation. The CoFe2O4 is an efficient and promising catalyst for the removal of PAM wastewater.

Recent years have witnessed increasing attempts to track trade flows of critical materials across world regions and along the life cycle for renewable energy and the low carbon transition. Previous studies often had limited spatiotemporal coverage, excluded end-use products, and modeled different life cycle stages as single-layer networks. Here, we integrated material flow analysis and complex network analysis into a multilayer framework to characterize the spatiotemporal and multilayer trade network patterns of the global cobalt cycle from 1988 to 2020. We found substantial growth and notable structural changes in global cobalt trade over the past 30 years. China, Germany, and the United States play pivotal roles in different layers and stages of the global cobalt cycle. The interlayer relationships among alloys, batteries, and materials are robust and continually strengthening, indicating a trend toward synergistic trade. However, cobalt ore-exporting countries are highly concentrated and rarely involved in later life cycle stages, resulting in the weakest relationship between the ore layer and other layers. This causes fluctuations and uncertainty in the global cobalt trade. Our model, linking industrial ecology, supply chain analysis, and network analysis, can be extended to other materials that are critical for the future green transition.

BACKGROUND: Cobalt, an essential trace element, is vital for maintaining human nervous system function, aiding in DNA synthesis, and contributing to red blood cell production. It is helpful for disease diagnosis and treatment plan evaluation by precisely monitoring its concentration changes in the human body. Despite extensive efforts made, due to its ultra-low concentration, the current limit of detection (LOD) as reported is still inadequate and cannot be satisfied with the precise clinical applications. Therefore, it is crucial to develop novel label-free sensors with high sensitivity and excellent selectivity for detecting trace amounts of Co2+.
RESULTS: Here, an ultrasensitive optical fiber SPR sensor was designed and fabricated for label-free detection of Co2+ with ultra-low concentration. It is achieved by modifying the carboxyl-functionalized CQDs on the AuNPs/Au film-coated hetero-core fiber, which can specifically capture the Co2+, leading to changes in the fiber\'s surface refractive index (RI) and subsequent SPR wavelength shifts in the transmission spectrum. Both the Au film and AuNPs on the fiber are modified with CQDs, leveraging their large surface area to enhance the number of active sites and probes. The sensor exhibits an ultra-high sensitivity of approximately 6.67 × 1019 nm/M, and the LOD is obtained as low as 5.36 × 10-20 M which is several orders of magnitude lower compared to other conventional methods. It is also experimentally demonstrated that the sensor possesses excellent specificity, stability, and repeatability, which may be adapted for detecting real clinical samples.
CONCLUSIONS: The CQDs-functionalized optical fiber SPR sensor exhibits substantial potential for precisely detecting Co2+ of trace amounts, which is especially vital for scarce clinical samples. Additionally, the sensing platform with sample sensor fabrication and measurement configuration introduces a novel, highly sensitive approach to biochemical analysis, particularly adapting for applications involving the detection of trace targets, which could also be employed to detect various biochemical targets by facile modification of CQDs with specific groups or biomolecules.

BACKGROUND: Fluoroquinolones (FQs) are widely used for their excellent antimicrobial properties, yet their release into aquatic environments pose risks to ecosystems and public health. The accurate monitoring and analysis of FQs present challenges due to their low concentrations and the complex matrices found in actual environmental samples. To address the need for auto-pretreatment and on-line instrumental analysis, developing new microextraction materials and protocols is crucial. Such advancements will provide better analytical assurance for the effective extraction and determination of FQs at trace levels, which is of great significance to environmental protection and human health.
RESULTS: In this work, we presented a Co2+ mediated paper-based molecularly imprinted polymer chip (CMC@Co-MIP), combined with UPLC analysis, to develop an effective analytical method for identifying and quantifying trace amounts of ciprofloxacin (CIP) and enrofloxacin (ENR) in water samples. Notably, the addition of Co2+ in CMC@Co-MIP helped to capture the template molecule CIP through coordination before imprinting, which significantly improved the ordering of the imprinted cavities. CMC@Co-MIP exhibited a maximum adsorption capacity up to 500.20 mg g-1 with an imprinting factor of 4.12, surpassing previous reports by a significant margin. Furthermore, the enrichment mechanism was extensively analyzed by various characterization techniques. The developed method showed excellent repeatability and reproducibility (RSD < 13.0 %) with detection limits ranging from 0.15 to 0.21 μg L-1 and recoveries ranging from 64.9 % to 102.3 % in real spiked water samples.
CONCLUSIONS: We developed a novel microextraction paper-based chip based on Co2+ mediation, which effectively improved the selectivity and convenience of extracting FQs. This breakthrough allowed the chip to have a high enrichment efficiency as well as provide a robust on-line instrumental program. It also confirms that the imprinting scheme based on metal ion coordination is a high-performance strategy.

The synthesis of cobalt nanocrystal-graphene quantum dot-Ti3C2TX monolithic film electrode (Co-GQD-Ti3C2TX) is reported via self-assembly of Ti3C2TX nanosheets induced by protonated arginine-functionalized graphene quantum dot and subsequent reduction of cobalt (III). The resulting Co-GQD-Ti3C2TX shows good monolithic architecture, mechanical property, dispersibility and conductivity. The structure achieves excellent supercapacitor and sensing behavior. The self-charging supercapacitor produced by printing viscous Co-GQD-Ti3C2TX hydrogel on the back of flexible solar cell surface provides high specific capacitance (296 F g-1 at 1 A g-1), high-rate capacity (153 F g-1 at 20 A g-1), capacity retention (98.1% over 10,000-cycle) and energy density (29.6 W h kg-1 at 299.9 W kg-1). The electrochemical chip produced by printing Co-GQD-Ti3C2TX hydrogel on paper exhibits sensitive electrochemical response towards uric acid. The increase of uric acid between 0.01 and 800 μM causes a linear increase in differential pulse voltammetry signal with a detection limit of 0.0032 μM. The self-powered sensing platform integrating self-charging supercapacitor, electrochemical chip and micro electrochemical workstation was contentedly applied to monitoring uric acid in sweats and shows one broad application prospect in wearable electronic health monitoring device.

Micro-LiNiCoMnO2 (MNCM), a cathode material with highest market share, has increasing demand with the growth of lithium battery industry. However, whether MNCM exposure brings adverse effects to workers remains unclear. This study aimed to explore the association between MNCM exposure with systemic inflammation and cardiac function. A cross-sectional study of 347 workers was undertaken from the MNCM production industry in Guangdong province, China in 2020. Metals in urine were measured using ICP-MS. The associations between metals, systemic inflammation, and cardiac function were appraised using a linear or logistic regression model. Bayesian kernel machine regression (BKMR) and generalized weighted quantile sum (gWQS) models were used to explore mixed metal exposures. The analysis of interaction and mediation was adopted to assess the role of inflammation in the relation between urinary metals and cardiac function. We observed that the levels of lithium (Li) and cobalt (Co) were positively associated with systemic inflammation and heart rate. The amount of Co contributed the highest weight on the increased systemic immune-inflammation index (SII) (59.8%), the system inflammation response index (SIRI) (44.3%), and heart rate (65.0%). Based on the mediation analysis, we estimated that SII mediated 32.3% and 20.9% of the associations between Li and Co with heart rate, and SIRI mediated 44.6% and 22.2% of the associations between Li and Co with heart rate, respectively. This study demonstrated for the first time that MNCM exposure increased the risk of workers\' systemic inflammation and elevated heart rate, which were contributed by the excessive Li and Co exposure. Additionally, it indicates that systemic inflammation was a major mediator of the associations of Li and Co with cardiac function in MNCM production workers.

In the title compound, [Co(C8H6N3O2)Cl(C2H5OH)] n , the CoII atoms adopt octa-hedral trans-CoN2O4 and tetra-hedral CoCl2O2 coordination geometries (site symmetries and m, respectively). The bridging μ3-O:O:N 2-(benzotriazol-1-yl)acetato ligands connect the octa-hedral cobalt nodes into (010) sheets and the CoCl2 fragments link the sheets into a tri-periodic network. The structure displays O-H⋯O hydrogen bonding and the ethanol mol-ecule is disordered over two orientations.

A cobalt-catalyzed intramolecular Markovnikov hydroalkoxycarbonylation and hydroaminocarbonylation of unactivated alkenes has been developed, enabling highly chemo- and regioselective synthesis of α-alkylated γ-lactones and α-alkylated γ-lactams in good yields. The mild reaction conditions allow use of mono-, di- and trisubstituted alkenes bearing a variety of functional groups. Preliminary mechanistic studies suggest the reaction proceeds through a CO-mediated hydrogen atom transfer (HAT) and radical-polar crossover (RPC) process, in which a cationic acylcobalt(IV) complex is proposed as the key intermediate.

A solid-state electrochemiluminescence (ECL) sensor was fabricated by immobilizing luminol, a classical luminescent reagent, on a Zn-Co-ZIF carbon fiber-modified electrode for the rapid and sensitive detection of procymidone (PCM) in vegetable samples. The sensor was created by sequentially modifying the glassy carbon electrode with Zn-Co-ZIF carbon fiber (Zn-Co-ZIF CNFs), Pt@Au NPs, and luminol. Zn-Co-ZIF CNFs, prepared through electrospinning and high-temperature pyrolysis, possessed a large specific surface area and porosity, making it suitable as carrier and electron transfer accelerator in the system. Pt@Au NPs demonstrated excellent catalytic activity, effectively enhancing the generation of active substances. The ECL signal was significantly amplified by the combination of Zn-Co-ZIF CNFs and Pt@Au NPs, which can subsequently be diminished by procymidone. The ECL intensity decreased proportionally with the addition of procymidone, displaying a linear relationship within the concentration range 1.0 × 10-13 to 1.0 × 10-6 mol L-1 (R2 = 0.993). The sensor exhibited a detection limit of 3.3 × 10-14 mol L-1 (S/N = 3) and demonstrated outstanding reproducibility and stability, making it well-suited for the detection of procymidone in vegetable samples.

Monolithic catalysts with excellent O3 catalytic decomposition performance were prepared by in situ loading of Co-doped KMn8O16 on the surface of nickel foam. The triple-layer structure with Co-doped KMn8O16/Ni6MnO8/Ni foam was grown spontaneously on the surface of nickel foam by tuning the molar ratio of KMnO4 to Co(NO3)2·6H2O precursors. Importantly, the formed Ni6MnO8 structure between KMn8O16 and nickel foam during in situ synthesis process effectively protected nickel foam from further etching, which significantly enhanced the reaction stability of catalyst. The optimum amount of Co doping in KMn8O16 was available when the molar ratio of Mn to Co species in the precursor solution was 2:1. And the Mn2Co1 catalyst had abundant oxygen vacancies and excellent hydrophobicity, thus creating outstanding O3 decomposition activity. The O3 conversion under dry conditions and relative humidity of 65%, 90% over a period of 5 hr was 100%, 94% and 80% with the space velocity of 28,000 hr-1, respectively. The in situ constructed Co-doped KMn8O16/Ni foam catalyst showed the advantages of low price and gradual applicability of the preparation process, which provided an opportunity for the design of monolithic catalyst for O3 catalytic decomposition.