Electrocatalytic hydrogenation (ECH) of aqueous phenol to cyclohexanone and cyclohexanol provides a sustainable strategy for simultaneous pollutant remediation and the synthesis of high-value chemicals. However, in both previous reports and our preliminary experiments, the liquid-phase product distributions often suffer from incomplete carbon balance that could not be explained by volatilization, adsorption, membrane crossover, or analytical error. Motivated by this imbalance, a sealed H-cell equipped with a gas-absorption trap was implemented to capture volatile products. A bimetallic PtRu electrode supported on carbon cloth, prepared by cyclic electrodeposition, was then evaluated under ambient conditions. With gas capture, cyclohexane was identified as a co-product with cyclohexanone and cyclohexanol, accounting for the previously “missing” carbon. The PtRu electrode exhibited a superior phenol conversion of 98.9% and a high faradaic efficiency (FE) of 59.5%, with product selectivity of ~32% cyclohexane, restoring the overall carbon balance to > 95%. In situ FT-IR spectroscopy revealed the dynamic changes of substances during the phenol hydrogenation process, including the attenuation of aromatic C=C and phenolic C–O bands, along with the growth of C=O/O–H features, which is consistent with stepwise hydrogenation. Density functional theory calculations indicated that the synergistic effect between Pt and Ru simultaneously enhanced the capture of phenol molecules and promoted electron transfer between electrode and surface-bound phenol, facilitating hydrogenation and subsequent C–O removal. This work reconciles the long-standing selectivity/carbon-balance gap in phenol ECH and provides a practical protocol for accurate product quantification and resource-oriented management of phenolic wastewater.

Spin-trapping agents-based electron paramagnetic resonance (EPR) is still widely used to detect hydroxyl radicals (•OH) in engineered environmental systems. Conventionally, the “four-line peak” of DMPO/•OH (1:2:2:1) was considered the gold standard for the presence of •OH, and signal intensity was occasionally applied to quantify •OH concentrations. Based on chemical reaction networks and reaction rate constants, we established a network dynamics model to quantitatively determine the concentrations of •OH and SO₄^•−. For example, when persulfate (S₂O₈^2–, 100 mmol/L, final pH = 3.33) was activated by FeS₂ (100 g/L), SO₄^•− concentration was 2.66 × 10⁻¹⁰ mol/L, 6 orders of magnitude higher than that of •OH (2.67 × 10⁻¹⁶ mol/L), while the concentration of DMPO/SO₄^•− (3.14 × 10⁻¹¹ mol/L) was 7 orders of magnitude lower than that of DMPO/•OH (2.34 × 10⁻⁴ mol/L). These results were validated by EPR. Our study revealed that 81.1%−81.5% of DMPO/•OH is derived from DMPO/SO₄^•− hydrolysis and only 18.5%−18.9% is from direct capture of •OH, questioning the reliability of detecting •OH based on the appearance of the “four-line peak”. Our study underscores the necessity of considering all the transformations among radicals and their adducts during EPR analysis, which also provides a direct and effective method for detecting other radicals with extremely short half-lives in other heterogeneous persulfate systems. The high sensitivity of SO₄^•− and •OH to pH also provides an avenue to regulate the generation of reactive species.

The control of NO_x emissions is of critical importance for improving air quality. Selective catalytic reduction of NOₓ with NH₃ (NH₃-SCR) remains the leading technology for NO_x abatement. This review systematically summarizes recent advances in typical metal oxide catalysts, including V-based, Ce-based, Fe-based, and Mn-based systems. It critically discusses the underlying reaction mechanisms and highlights the pivotal roles of catalyst supports, additives, morphology, pretreatment, preparation methods, and synergistic effects between different metal components in determining catalytic activity and poisoning resistance. Furthermore, a comprehensive analysis of the practical challenges posed by complex flue gas compositions—including H₂O, SO₂, P, and heavy or alkali metals—is provided. For V-based catalysts, regeneration methods are discussed in detail. In contrast to conventional V-based systems, the challenges associated with the industrial application of non-vanadium catalysts are also summarized, with particular emphasis on their durability under real-world conditions and resistance to flue gas components. Finally, we present perspectives and outline future research directions aimed at guiding the development of next-generation SCR catalysts, with a focus on elucidating reaction mechanisms under complex conditions and bridging the gap between laboratory-scale research and practical industrial application.

Energy-storage deployment in renewable projects is often assessed without considering when storage is manufactured and replaced, or how rapidly supporting grids decarbonize across regions. This study develops a prospective dynamic life-cycle assessment framework to evaluate the climate value of floating photovoltaic (FPV)-storage systems across China’s provincial grids. The framework links province-specific grid decarbonization trajectories with year-specific life-cycle emissions from FPV systems coupled with lithium iron phosphate batteries (LFP), vanadium redox flow batteries (VRFB), and pumped hydro storage (PHS), and quantifies net climate benefit using marginal carbon abatement efficiency (MCAE). Accounting for temporal changes in grid carbon intensity during storage replacement substantially revises replacement-phase emissions relative to static assessment. Results reveal strong spatial heterogeneity in storage climate value. Under the modelling assumptions adopted here, PHS generally achieves the highest MCAE, followed by LFP and VRFB. In hydropower-dominated low-carbon provinces such as Sichuan, MCAE can become negative, indicating that adding storage to FPV systems may increase rather than reduce life-cycle CO₂ emissions. The zero-benefit analysis suggests a model-dependent grid carbon-intensity screening zone of approximately 0.14–0.24 kg CO₂/kWh under the tested sensitivity range, rather than a generally applicable threshold. These findings indicate that uniform storage mandates may misallocate decarbonization effort, and that storage deployment should be differentiated according to regional grid conditions, storage technology, and deployment timing.

Arsenic (As) pollution in mining areas has become a critical global environmental issue. In particular, the excessive accumulation of As(V) in edible plants has raised significant concerns for food safety and human health. However, the mechanisms by which different concentrations of ferrous ion (Fe²⁺) influence phytotoxicity, As(V) uptake, and related metabolic processes remain unclear. In this study, we found that As(V) exposure significantly reduced biomass, root length, photosynthetic pigments and Fe content of Brassica chinensis L., inhibiting overall growth and development of the plant. As(V) triggered oxidative stress by generating excessive reactive oxygen species (ROS), which disrupted cellular homeostasis. Exogenous Fe²⁺ treatment, especially at 50 μmol/L, markedly enhanced the activities of key antioxidant enzymes, including SOD and POD, effectively mitigating oxidative damage. In addition, Fe²⁺ restricted As(V) uptake by promoting the formation of an adsorbed iron oxide film on the root surface and was associated with reduced expression of PHT1;4 in root tissues. Metabolomic analysis further demonstrated that Fe²⁺ treatment was associated with enhanced flavonoid biosynthesis pathways and increased accumulation of flavonoids under As(V) stress, which may contribute to improving plant tolerance. These findings underscore the protective role of Fe²⁺ against As(V) toxicity in Brassica chinensis L. and provide a potential strategy for mitigating risks to human food safety caused by As(V) contamination.

In this study, a two-stage upflow anaerobic sludge blanket-anoxic/oxic (UASB-A/O) coupled reactor system was developed for the rapid start-up of high-ammonium wastewater treatment, with partial denitrification-Anammox (PD/A) as the core nitrogen-removal pathway. Rapid start-up was assessed based on stable nitrogen-removal performance, sustained nitrite availability for Anammox, and enrichment of Anammox-related bacteria. The operating performance and microbial community succession were evaluated over 166 d of continuous operation under progressively increasing influent NH₄⁺-N concentrations. The front-end UASB reactor maintained a nitrogen-removal efficiency of 84% ± 1%, whereas the whole coupled system achieved a total inorganic nitrogen-removal efficiency of 98% ± 1%, indicating efficient deep nitrogen removal under high loading conditions. Microbial community analysis revealed a clear spatiotemporal succession during start-up. The community gradually shifted from mixed flora to a functionally stratified consortium. The UASB reactor and the anoxic zone were dominated by heterotrophic denitrifying bacteria, whereas the downstream aerobic zones were enriched with ammonia-oxidizing and anaerobic ammonia-oxidizing bacteria. The initially abundant non-target genus Arenimonas was gradually replaced by functional taxa, with the abundances of Thauera and Candidatus Kuenenia increasing by 19% and 3%, respectively. Functional gene analysis revealed that narG/napA, amoA/amoB/amoC/hao, and hzs/hdh were enriched, which supported the coupling of partial denitrification and Anammox. Overall, the two-stage UASB-A/O system achieved rapid start-up, near-complete nitrogen removal, and directional microbial succession, suggesting its potential for the efficient treatment of high-ammonium wastewater.

Organic aerosols (OA) are complex mixtures comprising thousands of compounds, posing challenges for molecular characterization. Liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) is a powerful tool for the analysis of OA. The selection of extraction solvents critically influences the molecular characterization of OA in LC-HRMS, yet selection biases are poorly understood. In this study, we systematically evaluated the extraction efficiencies of three commonly used solvents—methanol (MeOH), acetonitrile (ACN), and an ACN/H₂O mixture (8:2, v/v)—for diverse OA samples using HPLC-Orbitrap MS/MS. The sample set encompassed seasonal ambient PM_2.5 collected in a Chinese megacity, and aerosols emitted from cooking, coal combustion, and biomass burning. Generally, MeOH was the optimal solvent for non-targeted screening of ambient aerosols, yielding the broadest compound coverage and the highest signal intensities. However, ACN exhibited superior extraction efficiency for cooking and coal combustion aerosols, showing distinct selectivity towards compounds with higher carbon number (nC), higher DBE and lower OSc, particularly for aromatic and nitrophenolic compounds. ACN/H₂O extracted compounds with lower nC, DBE and higher OSc. It showed higher signal intensity for species containing hydrophilic functional groups, such as amines, pyridines, carbonyl compounds, polycarboxylic acids, and carbohydrates. This selectivity indicates that solvent selection may introduce relative quantification biases for specific compounds. The evaluation of procedural contamination revealed that ACN is most severely affected by procedural contaminants, particularly for long-chain fatty acid amides, aromatic and aliphatic amines from polypropylene plasticware. This study provided critical insights for optimizing solvent selection in non-targeted LC-HRMS analysis.

Starch wastewater (SW) has high organic loading (OL), rapid biodegradability, and strong oxygen demand, which often cause unstable treatment performance and excessive energy consumption in conventional aerobic processes. Magnetic field (MF) application was investigated as an auxiliary strategy to promote the magneto-bio-production of extracellular polymeric substances (EPS) during SW treatment, wherein a static MF served as a non-chemical stimulus for biological EPS generation in an aerobic sequencing batch reactor (SBR). The MF maintained chemical oxygen demand (COD) and soluble COD (SCOD) removal in the aerobic SBR at above 96.8% under low-to-medium OL conditions under six operational scenarios with varying OL and dissolved oxygen (DO) levels. Such stabilization could be attributed to MF-reinforced sludge structure with increased diameter of 247.7 µm and fractal dimension up to 0.41, which substantially reduced system sludge volume index and achieved high-quality effluent. Moreover, interfloc viscosity and aggregation were improved, with bound-EPS secretion of up to 80.22 mg/g mixed liquor suspended solids (MLSS). EPS flocculation rates reached 88.3%, thereby demonstrating potential for high-value applications. Mechanistically, MF enriches EPS-producing and magnetotactic bacteria (MTB), like Flavobacterium and Cloacibacterium. It also reorients intracellular metabolism by reinforcing the tricarboxylic acid (TCA) cycle and suppressing gluconeogenesis to accelerate glycolysis. The metabolic alteration expands α-ketoglutarate and succinate pools, thereby increasing the availability of amino acid and sugar precursors. Consequently, Kyoto Encyclopedia of Genes and Genomes (KEGG)-based functional redistribution may support the coordinated synthesis of proteinaceous EPS enriched in glutamate, histidine, valine, and polysaccharide EPS dominated by rhamnose, xylose, and fucoidan, whereas MTB-mediated spatial organization may further promote EPS retention and matrix stabilization. Comparative evaluation suggested that low-to-medium OL with medium DO was optimal for maximizing EPS production and sludge structural stability. Importantly, MF can enhance the stability and robustness of SW treatment through EPS-mediated sludge aggregation, community structure changes, and metabolic shifts, thereby enabling value-added EPS production.

Human hair integrates long-term mineral and metal exposure and serves as a convenient, noninvasive biomarker. Hair samples from 30 adult residents who had long-term residence in Nanning were analyzed for 20 elements. Mean concentrations were ranked as Ca > Na > Zn > K > Mg > Cu > Fe > Sr > Ba > Ti > As > Pb > Mn > Ni > Cr > Se > Mo > V > Cd > Co. The correlation-based clustering identified three major co-variation modules: 1) a hard-water and carbonate background-related pattern; 2) a possible dust-related Fe-Ti pattern with partial contribution from Mn; and 3) a heavy-metal co-variation pattern involving V-Cr, Pb-Cd, and partially Ni. OPLS-DA clearly distinguished sex-related differences in elemental composition. Hair samples from females exhibited higher concentrations of Ca, Mg, Zn, Sr, and Co, whereas Na and K concentrations were higher in male hair. Age was negatively correlated with Fe (r = −0.386) and Mn (r = −0.403). In regional comparisons, human hair from Nanning residents was enriched in Na, K, Zn, and Ba, while Fe, Mn, Cr, Pb, Cd, and Ni exhibited relatively lower levels. Collectively, hair from Nanning residents was characterized by enrichment in nutritional and electrolyte elements and the consistently lower concentrations of several transition and toxic metals. Sex and age contributed substantially to inter-individual heterogeneity. This pilot dataset provides preliminary evidence for the elemental patterns in human hair from the Nanning region and may serve as a basis for future larger-scale studies.

Heterogeneous catalytic ozonation (HCO) has emerged as a promising route for eliminating refractory organic contaminants from wastewater, relying on catalyst-assisted ozone activation to generate reactive oxygen species (ROS). However, the low electron transfer efficiency between active sites of the catalyst and ozone molecules hinders the efficient and sustainable ROS generation, thereby impacting the overall HCO performance. Herein, we propose a ligand-based strategy for expediting electron transfer and valence circulation of catalyst for HCO. We found that oxalic acid (OA), a representative terminal product generated during the ozonation of various aromatic organics, induced a 3.3-fold increase in the rate constant of catalytic ozonation of ibuprofen (IBU) by CeO₂, surpassing other low-molecular-weight organic acids. Experiments and characterizations proved that OA not only accelerated the Ce³⁺/Ce⁴⁺ valence cycle for activating ozone into hydroxyl radical (·OH), but also could be transformed into carbon-centered radicals (C₂O₄^•− and CO₂^•−) that participated in the degradation of pollutants, achieving a dual-pathway synergy to promote the catalytic performance of HCO. Moreover, we unveiled that the self-accelerating phenomenon of OA prevailed in the HCO of multi-structured pollutants. Overall, these findings highlight the potential of organic ligands to regulate electron transfer processes and redox dynamics in catalytic ozonation, offering new insight into the design of more efficient water treatment systems.

Airborne pathogens in densely populated indoor environments threaten public health, yet traditional ultraviolet disinfection suffers from photoreactivation-induced microbial regrowth. This study developed a synergistic air disinfection strategy simultaneously generating strong electric fields and electrodeless ultraviolet radiation through microwave synchronization. Microwave electric fields achieved 2.02 and 1.65 log inactivation of Escherichia coli and Bacillus subtilis, respectively; individual ultraviolet irradiation achieved 2.85 and 2.10 log. Under combined treatment (150 W microwave, 0.8 mW/cm² UV), inactivation rates reached 4.98 and 4.32 log, exceeding the arithmetic sum of individual treatments (4.87 and 3.75 log) by 47% and 32%. Mechanistically, electric fields induced membrane electroporation while UV caused DNA damage; the dual attack inhibited photoreactivation and repair. COMSOL simulations confirmed that experimental 150 W conditions generated localized 14 kV/cm fields, causing cell wall transmembrane potential to exceed the 1.0 V threshold while cytoplasmic membranes remained sub-threshold due to outer envelope shielding, confirming spatial selectivity. Response surface optimization reduced energy consumption by 42%. These findings establish a theoretical framework for next-generation air disinfection systems.

Cadmium (Cd) contamination in farmland soils poses a significant threat to agricultural sustainability and environmental safety. Although research on soil and crop Cd pollution has expanded, systematic comparative analyses of how different remediation materials affect core soil properties, Cd bioavailability, and crop attributes remain limited. To address this gap, we performed a meta-analysis of data from 116 published studies spanning the past 15 years. This study evaluates the efficacy of various remediation materials, including mixed amendments, synthetic agents, natural minerals, organic materials, and biochar, in remediating Cd-contaminated farmland. Biochar most comprehensively improved soil properties such as pH, soil organic matter (SOM), and available phosphorus, with pronounced enhancement of available P (effect size > 1) and cation exchange capacity (CEC) (effect size > 0.4), while effectively reducing soil bioavailable Cd (effect size = −0.37) and exchangeable Cd (effect size = −0.24). The consistency of biochar performance between pot and field experiments supports the translatability of laboratory findings to practical applications. Biochar efficacy was modulated by its properties: alkaline biochar was more effective at improving soil fertility, and biochar produced at temperatures above 600 °C exhibited stronger Cd immobilization capacity. Furthermore, biochar combined with other materials (biochar + x) outperformed biochar alone. This study addresses a critical gap in the evaluation of single remediation agents, clarifies the scientific basis for material selection, and establishes an integrated research framework from agent screening to field application.

Achieving simultaneous high-efficiency nitrogen removal and membrane fouling control remains a critical challenge in Membrane Bioreactor (MBR) technology. In this study, we investigated the integration of microgranular activated carbon (μGAC) into a flat-sheet MBR to enhance system performance. By strategically optimizing the sludge retention time (SRT) to 20 d, the system maintained a high concentration of functional biomass, which, when coupled with the fluidized state of μGAC, established a highly efficient simultaneous nitrification and denitrification (SND) environment. The biofilm on μGAC exhibited a relatively high total abundance of nitrogen-removing and organic-degrading bacteria, and the SND rate in the μGAC–MBR was 85.53%, representing a 12.00% increase over the control MBR (C–MBR). The long-term running μGAC–MBR system achieved an average total nitrogen (TN) removal efficiency of 82.74% and near-complete ammonia oxidation of 99.73%. The addition of μGAC modified sludge properties by reducing the protein-to-polysaccharide (PN/PS) ratio and increasing sludge hydrophilicity, resulting in a 14.5% reduction in membrane flux decline. Metagenomic analysis revealed that the μGAC–MBR selectively enriched K-strategist genera, specifically Nitrosospira and Nitrospira, which increased in abundance by 11.22% within the membrane cake layer. Furthermore, the significantly upregulated expression of key functional genes involved in carbon metabolism (yvaK and exaA) and nitrogen cycling (amoC, nirB, and norC) demonstrated a strengthened metabolic capacity for ammonium conversion. These results suggest that μGAC acts as a selective catalyst for a robust, K-strategist–dominated microbial community, thus providing enhanced denitrification and superior fouling resistance.

Surface ozone pollution in the Pearl River Delta (PRD) is strongly modulated by mesoscale weather patterns (MWPs), which govern the emission, transport, and chemical evolution of ozone and its precursors. To develop weather-specific control strategies, we used unsupervised classification to identify four characteristic MWPs associated with ozone exceedance days in the PRD during 2015–2023: spring/fall convergence between inland and coastal flow near the PRD estuary (MWP-1), spring coastal convergence between inland flow and sea breeze (MWP-2), summer/early-fall warm stagnant conditions under the Subtropical High (MWP-3), and summer/early-fall weak northerlies under typhoon influence (MWP-4). MWP-3 accounted for the largest share of exceedance days (35.4%), whereas MWP-4 led to the highest regional mean MDA8 ozone concentration (153.5 µg/m³). Using adjoint sensitivity modeling for representative ozone episodes in Shenzhen, we quantified ozone responses to precursor emissions under each MWP. Industry and transportation were identified as the dominant anthropogenic sectors, with ship emissions contributing under certain MWPs. Key precursor groups consistently included alkenes, alkanes, aromatics, and CO. Moreover, emissions beyond PRD and from the preceding day also contributed substantially to ozone exceedance in Shenzhen. A 10% reduction in emissions from targeted areas, sectors, and precursors lowered daytime ozone in Shenzhen by 4.1–5.9 µg/m³, compared with 1.1–2.1 µg/m³ for a uniform 10% reduction of anthropogenic precursor emissions within the PRD. These findings demonstrate a weather-aware framework for air quality management to optimize emission control and improve ozone mitigation in the PRD and other regions with similar meteorology–pollution linkages.

As prevalent emerging contaminants, organophosphate esters (OPEs) are widely detected in aquatic ecosystems. However, few studies have systematically compared their bioaccumulation and trophodynamics across different aquatic food webs. In this study, a total of 34 species (n = 498) were collected from Liaodong Bay (LDB) and Songhua River (SHR). Tri-n-propyl phosphate (TPP) and tris (2-chloroethyl) phosphate (TCEP) were the predominant OPEs in the organisms from LDB and SHR, respectively, with median concentrations of 147 and 266 ng/g lipid weight, lw. Low bioaccumulation was observed for 8 OPEs in LDB because their logarithmic bioaccumulation factors (log BAFs) were all below 3.7. In SHR, phytoplankton exhibited the strongest accumulation capacity for most OPEs, with the exception of TCEP. Overall, most OPEs presented higher bioaccumulation potential in freshwater food webs than in marine ones. TCEP and tris(2-ethylhexyl) phosphate (TEHP) had the highest biota-sediment accumulation factor (BSAF) in SHR (87.0) and LDB (248), respectively. A hump-shaped relationship between log K_ow and log BAF suggested that OPEs with moderate hydrophobicity were more susceptible to bioaccumulation. Eight OPEs underwent biodilution in LDB; only TCEP displayed distinct biomagnification (trophic magnification factor = 1.75) in SHR, whereas other congeners showed biodilution. Salinity, pH and dissolved organic carbon exerted distinct effects on the bioaccumulation and trophodynamics of different OPEs. TCEP in most organisms in SHR may pose potential cancer risk, with the incremental lifetime cancer risk ranging from 10^–6 to 10^–4. This finding provides reliable field data and scientific support for differentiated ecological risk control of OPEs in diverse aquatic environments.