Single Metal Research Articles

Assessment of health risks based on different populations and sources of heavy metals on agricultural lane in Tengzhou City by APCS-MLR models.

To identify the sources of heavy metals in local soils and their risks to human health. This study quantified the concentrations of eight heavy metals in 504 soil samples collected in Tengzhou, China. The ecological risks of a single heavy metal (EI), a comprehensive ecological risk index (RI), and a health risk assessment model were used to evaluate the level of contamination in the city. The results of the research study indicate that there are different levels of heavy metal pollution in rural and urban agricultural areas in Tengzhou. Moreover, the spatial variability of mercury (Hg) is considerable, reaching 0.96, indicating a significant impact of anthropogenic activities. For the ecological risk, the heavy metal element with the highest EI value was mercury with a mean value of 67.22 and a peak value of 776.00. The heavy metal with the lowest mean EI value was Zn with only 1.03. Meanwhile, the average RI is only 128.59, but some areas have an RI as high as 842.2. The sources of heavy metals were identified using principal component analysis, correlation analysis, and an absolute principal component score multiple linear regression model (APCS-MLR). The non-carcinogenic risk for children, the carcinogenic risk for children, and the carcinogenic risk for adults were 1.23, 2.42×10-4 and 1.00×10-4, respectively, and these values exceeded their respective recommended values, and As and Cr had some carcinogenic hazards. Heavy metals in the soil come from natural, industrial, traffic and agricultural sources and represent 39.59%, 29.48%, 25.17% and 5.77%, respectively. The main source of heavy metals in local agricultural soils is the geological background, and the government needs to strengthen the monitoring of As and Cr in drinking water resources, as well as reduce traffic pollution and factory waste emissions to reduce Hg in soils.

Emerging insights into the application of metal-organic framework (MOF)-based materials for electrochemical heavy metal ion detection

Heavy metal ions are one of the main sources of water pollution, which has become a major global problem. Given the growing need for heavy metal ion detection, electrochemical sensor stands out for its high sensitivity and efficiency. Metal-organic frameworks (MOFs) have garnered much interest as electrode modifiers for electrochemical detection of heavy metal ions owing to their significant specific surface area, tailored pore size, and catalytic activity. This review summarizes the progress of MOF-based materials, including pristine MOFs and MOF composites, in the electrochemical detection of various heavy metal ions. The synthetic methods of pristine MOFs, the detection mechanisms of heavy metal ions and the modification strategies of MOFs are introduced. Besides, the diverse applications of MOF-based materials in detecting both single and multiple heavy metal ions are presented. Furthermore, we present the current challenges and prospects for MOF-based materials in electrochemical heavy metal ion detection.

Transition metal atoms embedded into B/N co-doped graphene as electrocatalysts toward nitrogen reduction reaction: Search for the optimal combination

The catalytic performance of a series of single transition metal (TM = 3d, 4d, and 5d series) atoms anchored on B/N co-doped graphene (BxNy@Gra) toward electrocatalytic nitrogen reduction reaction (eNRR) was systematically investigated by first-principles calculations. Among 180 possible materials, four catalysts (Tc-B1N3@Gra, Os-B2N2α@Gra, Re-B2N2γ@Gra, Nb-B3N1@Gra) feature the highest activity with UL no higher than 0.31 V. Interestingly, a volcano curve between UL and ΔEads(*NNH) can be established, so ΔEads(*NNH) can be applied as a descriptor to unveil the structure-activity relationship and characterize the activity of catalysts. The properties, thermal stability, and selectivity for the four catalysts were analyzed. Os-B2N2α@Gra is identified as a promising catalyst in this work for catalyzing N2 electroreduction to NH3 owing to its potent catalytic activity (UL = −0.28 V), high stability and distinct selectivity. This work can give some meaningful guidance for rapid screening and the rational design of efficient single-atom catalysts for electrocatalytic ammonia synthesis and other related electrochemical reaction. We expect that the present study will inspire and promote the efforts from both experimental and theoretical in this direction.

Platinum‐Group Metal High‐Entropy Selenides for the Hydrogen Evolution Reaction

The selenides of platinum‐group metals (PGMs) are emerging as promising catalysts for diverse electrochemical reactions. To date, most studies have focused on single metal or bimetallic systems, whereas the preparation of a high‐entropy (HE) selenide consisting of five or more PGM elements holds the promise to further enhance catalytic performance by introducing abundant active sites with various local coordination environments and electronic structures. Herein, we report for the first time the synthesis of PGM‐based HE‐Selenide (HE‐Se) nanoparticles with a unique amorphous structure. The atomic metal–Se coordination and the presence of short‐range order were thoroughly revealed. It is further shown that the amorphous HE‐Se can be facilely transformed into a single‐phase crystalline HE‐Se with a cubic structure by thermal annealing. Catalytically, the amorphous HE‐Se showed better acidic hydrogen evolution activity over monometallic PGM‐based selenides and the crystalline counterpart, demonstrating the advantages of high‐entropy configuration and amorphous structure. Our findings may pave the way toward the synthesis and property exploration of amorphous PGM‐based selenides with tunable compositions.

Platinum-Group Metal High-Entropy Selenides for the Hydrogen Evolution Reaction.

The selenides of platinum-group metals (PGMs) are emerging as promising catalysts for diverse electrochemical reactions. To date, most studies have focused on single metal or bimetallic systems, whereas the preparation of a high-entropy (HE) selenide consisting of five or more PGM elements holds the promise to further enhance catalytic performance by introducing abundant active sites with various local coordination environments and electronic structures. Herein, we report for the first time the synthesis of PGM-based HE-Selenide (HE-Se) nanoparticles with a unique amorphous structure. The atomic metal-Se coordination and the presence of short-range order were thoroughly revealed. It is further shown that the amorphous HE-Se can be facilely transformed into a single-phase crystalline HE-Se with a cubic structure by thermal annealing. Catalytically, the amorphous HE-Se showed better acidic hydrogen evolution activity over monometallic PGM-based selenides and the crystalline counterpart, demonstrating the advantages of high-entropy configuration and amorphous structure. Our findings may pave the way toward the synthesis and property exploration of amorphous PGM-based selenides with tunable compositions.

Combination of nanoparticles with single-metal sites synergistically boosts co-catalyzed formic acid dehydrogenation

The development of hydrogen technologies is at the heart of a green economy. As prerequisite for implementation of hydrogen storage, active and stable catalysts for (de)hydrogenation reactions are needed. So far, the use of precious metals associated with expensive costs dominates in this area. Herein, we present a new class of lower-cost Co-based catalysts (Co-SAs/NPs@NC) in which highly distributed single-metal sites are synergistically combined with small defined nanoparticles allowing efficient formic acid dehydrogenation. The optimal material with atomically dispersed CoN2C2 units and encapsulated 7-8 nm nanoparticles achieves an excellent gas yield of 1403.8 mL·g−1·h−1 using propylene carbonate as solvent, with no activity loss after 5 cycles, which is 15 times higher than that of the commercial Pd/C. In situ analytic experiments show that Co-SAs/NPs@NC enhances the adsorption and activation of the key intermediate monodentate HCOO*, thereby facilitating the following C-H bond breaking, compared to related single metal atom and nanoparticle catalysts. Theoretical calculations show that the integration of cobalt nanoparticles elevates the d-band center of the Co single atoms as the active center, which consequently enhances the coupling of the carbonyl O of the HCOO* intermediate to the Co centers, thereby lowering the energy barrier.

“One stone, two birds”: Salt template enabling porosity engineering and single metal atom coordinating toward high-performance zinc-ion capacitors

Zinc-ion hybrid capacitors (ZIHCs) have received increasing attention as energy storage devices owing to their low cost, high safety, and environmental friendliness. However, their progress has been hampered by low energy and power density, as well as unsatisfactory long-cycle stability, mainly due to the lack of suitable electrode materials. In this context, we have developed manganese single atoms implanted in nitrogen-doped porous carbon nanosheets (MnSAs/NCNs) using a metal salt template method as cathodes for ZIHCs. The metal salt serves a dual purpose in the synthesis process: It facilitates the uniform dispersion of Mn atoms within the carbon matrix and acts as an activating agent to create the porous structure. When applied in ZIHCs, the MnSAs/NCNs electrode demonstrates exceptional performance, including a high capacity of 203 mAh g−1, an energy density of 138 Wh kg−1 at 68 W kg−1, and excellent cycle stability with 91% retention over 10,000 cycles. Theoretical calculations indicate that the introduced Mn atoms modulate the local charge distribution of carbon materials, thereby improving the electrochemical property. This work demonstrates the significant potential of carbon materials with metal atoms in zinc-ion hybrid capacitors, not only in enhancing electrochemical performance but also in providing new insights and methods for developing high-performance energy storage devices.

The Role of Frustrated Lewis Pair in Catalytic Transfer Hydrogenation of Furfural using Nickel Single-Atom Catalysts: A Theoretical Study.

The burgeoning field of frustrated Lewis pair (FLP) heterogeneous catalysts has garnered significant interest in recent years, primarily due to their inherent ability to activate H-source molecules, such as H2, thereby facilitating hydrogenation reactions. However, the application of single metal atom catalysts incorporating FLP sites has been relatively under-explored. In this study, non-precious transition metal atoms were anchored onto a C2N framework with an intrinsic cavity and a defective N-C sheet. Theoretical calculations substantiated energy barriers as low as 0.10 eV for isopropanol activation, thereby positioning these catalysts as highly promising candidates for catalytic transfer hydrogenation of furfural. Electronic structure analyses revealed that the H-O bond breakage in isopropanol molecules was significantly facilitated by the presence of FLP sites within the catalysts. Notably, both Ni-C2N and Ni-N6-C demonstrated exceptional potential as selective catalysts for the hydrogenation of furfural into furfuryl alcohol, exhibiting remarkably low barriers of only 0.65-0.72 eV for the rate-determining steps, which are notably lower than those observed in many traditional catalysts. Theoretical investigations strongly imply that the construction of single atom catalysts with FLP sites could significantly enhance the activity and selectivity for hydrogenation reactions, thus stimulating the experimental synthesis of such catalysts.

Spin Manipulation of Heterogeneous Molecular Electrocatalysts by an Integrated Magnetic Field for Efficient Oxygen Redox Reactions.

Understanding the spin-dependent activity of nitrogen-coordinated single metal atom (M-N-C) electrocatalysts for oxygen reduction and evolution reactions (ORR and OER) remains challenging due to the lack of structure-defined catalysts and effective spin manipulation tools. Herein, both challenges using a magnetic field integrated heterogeneous molecular electrocatalyst prepared by anchoring cobalt phthalocyanine (CoPc) deposited carbon black on polymer-protected magnet nanoparticles, are addressed. The built-in magnetic field can shift the Co center from low- to high-spin (HS) state without atomic structure modification, affording one-order higher turnover frequency, a 50% increased H2O2 selectivity for ORR, and a ≈4000% magnetocurrent enhancement for OER. This catalyst can significantly minimize magnet usage, enabling safe and continuous production of a pure H2O2 solution for 100 h from a 100 cm2 electrolyzer. The new strategy demonstrated here also applies to other metal phthalocyanine-based catalysts, offering a universal platform for studying spin-related electrochemical processes.

Adsorption characteristics and mechanisms of individual and a quinary mixture of heavy metal ions on novel CoFe2O4-BiFeO3 nanosorbents in water

Application of CoFe2O4-BiFeO3 nanocomposites (CFO-BFO NCs) in highly adsorptive removal of heavy metal ions (Pb(II), Co(II), Cu(II), Cd(II) and Zn(II)) by individual and simultanoeous adsorption were investigated for the first time in the present study. The characterization of CFO-BFO NCs were analyzed by using XRD, VSM, SEM, TEM and BET techniques. The CFO-BFO NCs powder consists of characteristic peaks of BFO and CFO without any trace of other crystalline phases; they were uniformly dispersed with a size of about 3–5 nm, much smaller than single – phase CFO (10–25 nm) and BFO (5–10 µm) with the surface area of 84.93 m2/g; remanence and coercivity were 14.33 emu/g, 1.99 emu/g and 195 Oe, respectively, significantly decreased compared to CFO but significantly increased compared to BFO. The single or simultaneous adsorption of a quinary mixture of Pb(II), Co(II), Cu(II), Cd(II) and Zn(II) on CFO-BFO NCs followed the Freundlich isotherm model and the pseudo-second-order kinetic model. Adsorption capacity of single heavy metal ions were in the order Pb(II) > Co(II) > Cu(II) > Cd(II) > Zn(II) while the simultaneous adsorption was in the order Pb(II) > Cu(II) > Co(II) > Zn(II) > Cd(II). The maximum adsorption capacities (qmax) of each ion in the case of simultaneous adsorption were smaller than that for cases of the single adsorption but the total qmax of ions mixture was much higher than the highest qmax of single adsorption. The simultaneous adsorption of heavy metal ions is the competition, the best selectivity is Pb(II) and the strongest competition is Cd(II), the adsorption ability reduces as the charge and radius of interfering cation increase and the ionic strength increases. The regeneration and reuse ability were good, while the adsorption efficiency slightly decreased over three recycles. The adsorption increased slightly as temperature increased. The adsorption process was spontaneous and endothermic. Adsorption of heavy metal ions on CFO-BFO NCs consists of both electrostatic and chemisorption. The applicability for real sample is good. Our results demonstrate that the CFO-BFO NCs is a prospective adsorbent to remove Pb(II), Co(II), Cu(II), Cd(II) and Zn(II) from aqueous environment.

The key role of Sn in enhancing Rh recovery from spent automotive catalysts

The recovery of platinum group metals (PGMs) from spent automotive catalysts (SACs) is a promising solution to alleviate PGMs resource shortage and reduce environmental pollution caused by SACs. Nevertheless, the traditional iron capture method requires high smelting temperatures for effective PGMs recovery, leading to significant energy consumption. Therefore, experimenting with lower temperatures to achieve efficient recovery is both beneficial and challenging. The introduction of Sn for the Fe-Sn co-capture of Pt and Pd has been proven to be effective. However, the unique behavior and mechanism of Sn in capturing Rh remain unclear. In this paper, we conduct a detailed study on Sn's behavior in capturing Rh. Rh exhibits a different trend compared to Pt/Pd. Specifically, Sn demonstrates a significantly stronger ability to capture Rh than Pt/Pd, and its effectiveness surpasses that of Fe. Under optimized slag types and smelting conditions, the recovery efficiencies for Pt, Pd, and Rh increased by 20.55 %, 13.04 %, and 21.57 % respectively, compared to traditional single metal iron trapping, reaching 94.14 %, 93.42 %, and 93.76 %. DFT calculations indicate that the lattice substitution energy for PGMs entering the Sn lattice is lower than that for Fe, thus the introduction of Sn enhances the metal trap's ability to capture PGMs. This work provides an in-depth understanding of how the introduction of Sn enhances the recovery of PGMs, particularly Rh. It offers new theoretical guidance for efficiently recovering PGMs from SACs, benefiting the comprehensive recovery and utilization of PGMs.

The influence of operational factors on the photocatalytic degradation of methylene blue dye in aqueous Sr-Au-ZnO suspensions under UV-A light

Any of several processes that break down dyes, ideally into harmless chemicals, is referred to as industrial dye degradation. Water waste discharges various colors, particularly those used in the textile industry like methyl red and methylene blue, into ecosystems, leading to significant pollution of the water supply. Under UV-A irradiation, the photocatalytic degradation of a commercial heterocyclic aromatic chemical molecule called methylene blue (MB) has been investigated using an aqueous solution of Sr-Au-ZnO as a photocatalyst. Research has been done on how different process characteristics affect the degradation process. For the mineralization of MB dye under UV-A light, it was found that the optimized Sr-Au-ZnO was more effective than commercial catalysts (ZnO and benchmark photocatalyst Degussa P25), single metal dopants (Sr-ZnO, Au-ZnO), and prepared ZnO. The effects of operational parameters, such as the quantity of photocatalyst, dye concentration, and starting pH, on the photo-mineralization of MB are analyzed before optimal values are given. Chemical oxygen demand (COD) measurements have confirmed that MB is mineralized. Using GC–MS analysis, the intermediates produced during photodegradation were predicted, and an appropriate degradation pathway was suggested. This procedure can be used for treating wastewater from sewage since optimized Sr-Au-ZnO is reusable.

Intrinsic Activity Identification of Noble Metal Single-Sites for Electrocatalytic Chlorine Evolution.

Single-atom catalysts with maximal atom-utilization have emerged as promising alternatives for chlorine evolution reaction (CER) toward valuable Cl2 production. However, understanding their intrinsic CER activity have so far been plagued due to the lack of well-defined atomic structure controlling. Herein, we prepare and identify a series of atomically dispersed noble metals (e.g., Pt, Ir, Ru) in nitrogen-doped nanocarbons (M1-N-C) with an identical M-N4 moiety, which allows objective activity evaluation. Electrochemical experiments, operando Raman spectroscopy, and quasi-in situ electron paramagnetic resonance spectroscopy analyses collectively reveal that all the three M1-N-C proceed the CER via a direct Cl-mediated Vomer-Heyrovský mechanism with reactivity following the trend of Pt1-N-C > Ir1-N-C > Ru1-N-C. Density functional theory (DFT) calculations reveal that this activity trend is governed by the binding strength of Cl*-Cl intermediate (ΔGCl*-Cl) on M-N4 sites (Pt < Ir < Ru) featuring distinct d-band centers, providing a reliable thermodynamic descriptor for rational design of single metal sites toward Cl2 electrosynthesis.

A New Approach to Single‐Step Fabrication of TiOx‐CeOx Nanoparticles

Mixed metal oxide (MMO) nanoparticles (NPs) are hybrids consisting of two or more nanoscale metal oxides. Advantages of MMO NPs over single metal oxides include improved catalytic activity, enhanced electrical and magnetic properties, and increased thermal stability due to the synergy of the different oxide components. This study presents a novel fabrication route for TiO2‐CeO2 NPs enriched with oxygen vacancies using a Haberland‐type gas aggregation cluster source. The NPs, deposited from different segmented Ti/Ce targets under varying O2 addition, were examined with respect to final composition, morphology, and Ti, Ce surface oxidation states. Particle formation mechanisms are proposed for the observed morphologies. Additionally, available O2 during deposition and its impact on the formation of defective sites were investigated. Defective sites in TiO2‐CeO2 NPs were analyzed using transfer to X‐ray photoelectron spectroscopy and transmission electron microscopy without contact to ambient oxygen. The incorporation of Ce to the target exhibits synergistic effects on the synthesis process. Segmented Ti/Ce targets enable the deposition of a broad range of mixed oxide NPs with diverse compositions and morphologies at considerably enhanced deposition rates, which is vital for practical applications. The presented fabrication approach is expected to be applicable for a broad variety of MMO NPs.

Enrichment and Nutrition/Health Risks Assessment of Mineral Elements in Apples Growing in Yunnan's High Geological Background Area

Considering the extremely high content of soil mineral elements in high geological background areas, it is crucial to understand the transportation and health risks of mineral elements in soil-plant systems. In this study, 30 soil and apple-paired samples were collected from the main apple production areas of Yunnan's high geological background region to determine the contents of mineral elements. The aim was to research the enrichment characteristics, nutritional values, and health risks associated with 12 mineral elements in apples. The results revealed that Cd, As, Pb and Cr contents in soil samples exceeded their corresponding risk screening values with percentages of 50%, 17%, 48%, and 30%, respectively. However, only 13.3% of Pb content in apple samples exceeded the safety limit （0.1 mg·kg-1, fresh fruit）. In addition to the toxic elements, apples had higher contents of K, Ca, Mg, Mn, and Zn, with average contents of 1.241 g·kg-1, 0.045 g·kg-1, 0.061 g·kg-1, 0.648 mg·kg-1, and 0.944 mg·kg-1, respectively. The nutritional evaluation results showed that the index （INQ） of K and Cu were higher than 2 through the consumption of apples, suggesting that apple consumption was one of the primary sources of K and Cu intake. The health risk assessment revealed that the target hazard quotient （THQ） of a single heavy metal was： Cu &gt; As &gt; Cr &gt; Pb &gt; Zn &gt; Cd； the hazard index （HI） of all heavy metals was far lower than 1, indicating that apple consumption did not pose significant heavy metal exposure risks. The results of this study will provide a scientific insight into the nutritional aspects and health risks associated with mineral elements in soil-plant systems within high geological background areas.

Constructing ultralow-loading Cu single atoms/Fe2O3 particles on Nb2C MXenes for efficient utilization of atomic H to boost electrochemical debromination

Bromate is a commonly identified carcinogenic and genotoxic disinfection byproduct in water. Electrochemical debromination is an environmentally friendly and effective approach but it often suffers the limited reducing atomic H (H*) ability and high metal catalyst dosage. In this study, a unique composite catalyst comprised of ultra-low loading Cu single atoms (0.016 wt%) and Fe2O3 nanoparticles supported on a Nb2C MXene (denoted as Cu0.2/Fe0.1/Nb2C) was synthesized by one-step high-temperature molten salt method. The Cu0.2/Fe0.1/Nb2C significantly outperformed the Nb2C, Cu0.2/Nb2C and Fe0.1/Nb2C counterparts in the electrochemical debromination with a 94.2 % removal efficiency of bromate. It is revealed that the introducing of Cu single atoms, efficiently promotes the adsorption of H* and inhibition of competitive H2 evolution. The incorporation of Fe2O3 nanoparticles significantly increased the electronic metal-support interaction effect between the metal components and Nb2C, thereby forming a noticeable electronic cloud bridge to facilitate efficient charge transfer. Ultimately, the synergistic interplay between Cu single atoms and Fe2O3 nanoparticles plays a crucial role in achieving the remarkable removal performance of bromate. This work not only presents a significant instance of a synergistic catalyst involving metal single atoms and metal nanoparticles for effective electrochemical debromination but also advances the understanding of the electronic metal-support interaction.

Atomically dispersed nickel-bismuth dual-atom sites for high rate electrochemical CO2 reduction

We report a diatomic-site catalyst configuration constituted by Ni-N3 and Bi-N4 embedded in ultrathin nitrogenated carbon nanosheets (Ni/Bi-N-C) which showed dramatically improved activity and selectivity for the conversion of CO2 to CO. Specifically, the catalyst exhibited high CO Faradaic efficiency (FECO) of above 90 % over a wide potential window from −0.76 to −2.22 versus reversible hydrogen electrode with the maximum CO partial current density up to 312 mA cm−2 in a flow cell, and coupled with robust durability. Ni/Bi-N-C-based membrane electrode assembly (MEA) device presented ultrahigh FECO of 95.7 % at 750 mA and over 100 h of continuous operation without decay under constant current density of 100 mA cm−2. Mechanistic studies and density functional theory calculations reveal that regulating the CO2RR catalytic performance via nearby Ni and Bi active sites can potentially break the activity benchmark of the single metal counterparts because the neighboring Ni and Bi active sites work in synergy to decrease the reaction barrier for the formation of *COOH and desorption of *CO. This work presents an efficient combination of two metal atomic sites which was designed by optimizing the interaction between the atomic sites and key reaction intermediates, resulting in the high-rate electrocatalytic CO2 reduction.

Electrochemically Created Active Centers in a Bimetallic CoNi-Triazole Metal-Organic Framework for Enhanced Oxygen Evolution Reaction Activity.

Electrochemical water oxidation utilizing bimetallic CoNi-Tz (Tz = 1,2,4-triazole) framework is explored. Initially, CoNi-Tz possesses active tetrahedral Co center and electron-mediated octahedral Ni chain. After performing an electrochemical activation, the partial structural transformation on the Ni center occurs. This leads to the generation of excessive active centers which can promote catalytic activity of the framework. The activated CoNi-Tz catalyst displays a remarkably low OER overpotential of 293 mV at a current density of 10 mA cm-2 with a small Tafel slope of 49.98 mV dec-1, outperforming the single metal Co-Tz and benchmark IrO2 catalysts.

Associations of multiple serum metals with the risk of metabolic syndrome among the older population in China based on a community study: A mediation role of peripheral blood cells

Metal exposure has been reported to be associated with metabolic syndrome (MetS), however, the evidence remains inconclusive, particularly in elderly individuals. From May to July 2016, serum levels of 16 metals were measured using inductively coupled plasma mass spectrometry (ICP-MS) in 852 elderly individuals (≥65 years) residing in Wuhan, China. Biological detection and disease recognition were based on individual surveys conducted during health check-ups. Spearman’s rank correlation analysis was performed to identify the correlation among serum metals. The data were Ln-transformed to fit a normal distribution for further analyses. Linear and logistic regression were applied to explore the associations between metals and diseases. Restricted cubic spline (RCS) analysis was utilized to examine dose-response relationships. The Weighted Quantile Sum (WQS) score was applied to determine the empirical weights of each heavy metal in the context of their combined effect on metabolic diseases. The prevalence of MetS, hypertension, diabetes, and hyperlipidemia were 46.36 %, 68.90 %, 24.65 %, and 21.60 %, respectively. Serum metal mixture was positively associated with the prevalence of MetS (OR = 1.92, 95 % CI: 1.30–2.82), hypertension (OR = 1.50, 95 % CI: 1.01–2.23), and diabetes (OR = 2.18, 95 % CI: 1.48–3.22). In single metal models, we found that serum zinc levels were associated with an increased risk of MetS, while rubidium had a protective effect against MetS. Interestingly, different metals had distinct effects on specific diseases in this study: lithium and barium were more likely to influence blood pressure, while selenium had a more significant effect on blood glucose. Lipids were more susceptible to the effects of zinc, selenium, and strontium. Platelet count (PLT) and lymphocyte count (LYM) mediated the association between selenium exposure and hyperlipidemia, while neutrophil count (NEU) mediated the relationship between serum rubidium exposure and MetS. Our findings offer valuable etiological insights into the relationship between serum heavy metals and the prevalence of MetS, suggesting that peripheral blood cells may play a mediating role in this association.

TiO2-loaded phosphogypsum-modified biochar for the removal of ofloxacin and Cu2+: Performance, mechanisms, and toxicity assessment

The combined contamination of antibiotics and heavy metals usually occurs in aquaculture wastewater and has high ecological toxicity. Currently, most research only focuses on the removal of a single heavy metal or antibiotics, and there is little research on the simultaneous removal of both. Therefore, to effectively treat them, this study prepared TiO2-loaded phosphogypsum-modified biochar (TYBC450) for adsorption and photocatalytic removal of ofloxacin (OFL) and copper (Cu2+). The removal performance and mechanisms of OFL and Cu2+ were explored, and their ecological toxicity was assessed through zebrafish acute toxicity experiments. The results suggested a synergistic effect between OFL and Cu2+. The adsorption efficiencies of TYBC450 for OFL and Cu2+ were 88.16% and 90.87% (the adsorption capacities were 1.75 and 3.65 mg/g, respectively). Bridging, precipitation, and complexation effects were the main co-adsorption mechanisms. The photocatalytic efficiencies of OFL and Cu2+ were 91.23% and 72.09% (the rate constants were 0.0101 and 0.0045 min-1, respectively). OFL acted as a hole-trapping agent, while Cu2+ acted as an electron acceptor, hindering the combination of e- and h+. There were 12 intermediates in the OFL degradation process, which had lower toxicity than the mother organism. Both the cyclic regeneration and actual aquaculture wastewater application tests indicated that TYBC450 had potential application prospects.