SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4347-9
Overcoming the intrinsic loading ceiling of oxide-supported single-atom catalysts remains a long-standing challenge, because oxide frameworks generally provide limited capacity for accommodating high densities of isolated metal species. Here, we report a hollow TiO2 nanoreactor that effectively addresses the long-standing loading limitation of oxide-supported catalysts by coupling high-capacity ion exchange with structural confinement. The multiscale framework is derived from a sodium titanate hollow flower-sphere assembled from ultrathin nanosheets. It enables broad accessibility of exchange sites and facilitates high Cu uptake prior to oxide formation. Subsequently, during Ar-assisted transformation into oxygen-vacancy-rich TiO2, the incorporated Cu species remain highly dispersed within the framework, while vacancy-mediated metal–support interactions further enhance their stability. As a result, controllable Cu speciation is achieved at ultrahigh loadings of 7.4 wt% as spatially isolated single atoms and 12.4 wt% as single-atom/subnanometer-cluster hybrids. The optimized hybrid catalyst delivers a hydrogen evolution rate of 28.8 mmol g−1 h−1 under simulated sunlight, surpassing conventional low-loading Cu/TiO2 systems under comparable conditions. This strategy is readily extendable to other transition metals (Fe, Co, and Ni), establishing a structural design principle for constructing high-density and speciation-controlled metal sites on oxide supports.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2024110703
Urban river ecosystems are increasingly threatened by anthropogenic activities, necessitating comprehensive health assessments beyond conventional water quality metrics. This study evaluates the ecological health of the Zhongshan South Road reach in Wuhu, China, by integrating microbial community integrity with physicochemical parameters. Nine monitoring sections were established, considering land use, pollution sources, and seasonal hydrology. Over four seasons, eight water quality parameters and microbial indicators were systematically monitored. A Microbial Index of Biotic Integrity (M-IBI) was developed through candidate parameter screening, interference response analysis, and discriminant ability assessment. Core metrics included Chao1 index, Sobs index, and relative abundances of Acinetobacter and hgcl-clade genera. M-IBI scores were standardized and classified into health levels, with results compared against the Water Quality Index (WQI). Findings revealed seasonal M-IBI variation: winter > autumn > summer > spring, with downstream water quality superior to upstream. Spatial and seasonal patterns of WQI and M-IBI were largely concordant, though discrepancies arose from differential microbial responses to environmental factors and heightened sensitivity to human disturbance. The M-IBI approach demonstrated robust applicability for river health assessment, offering a sensitive, integrative tool for urban water management.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025092802
Activated carbon (AC) filters in drinking water treatment plants (DWTPs) experience significant adsorption performance decline over extended operation, yet complete media replacement is a major cost. To evaluate cost-effective strategies, pilot-scale column experiments with five AC replacement ratios (0%, 30%, 50%, 70%, and 100%) were conducted to assess removal of disinfection by-product (DBP) precursors and pesticide-related emerging contaminants. For dissolved organic matter (DOM), all fractions except low molecular weight compounds (LMWC) achieved >85% of the removal obtained with full replacement when 70% new AC was used, with UV254 removal reaching 70%. LMWC, due to small molecular size and low adsorption energy, required higher replacement ratios or full replacement for substantial removal. For DBPs, removal of trihalomethanes (THMs) and haloacetic acids (HAAs) was insensitive to replacement ratio, while haloacetaldehydes (HALs) removal improved markedly with increasing ratio, indicating structural selectivity. For pesticide-related contaminants, all except triazoles achieved >95% removal at 70% replacement; triazoles, due to high water solubility, high polarity, and low octanol-water partition coefficient, achieved only ~60% removal. Overall, replacing 70% of AC restored treatment performance to >80% of that with full replacement, ensuring effluent quality while saving ~30% of new carbon cost. Molecular structure, polarity, and pore size matching are key determinants of removal efficiency; optimizing replacement ratio balances water quality and economic benefits.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025051701
This study investigated the effects of selenium nanoparticles (SeNPs) on the growth, mycelium morphology, copper (Cu2+) removal rate, extracellular polymeric substances (EPS), and intracellular enzyme activity of Aspergillus flavus TL-F3 (A. flavus TL-F3) under Cu2+ stress. Results showed that different concentrations of Cu2+ inhibited the growth of A. flavus TL-F3. The highest Cu2+ removal rate of 56.32% was observed at a Cu2+ concentration of 50 mg·L−1. Under 50 mg·L−1 Cu2+ stress, 0.25 mg·L−1 SeNPs promoted the growth of A. flavus TL-F3, increasing its biomass by 2.71%, and significantly enhanced the fluorescence intensity of EPS, Na+/K+-ATPase activity, and decreased malondialdehyde (MDA) content, reduced superoxide dismutase (SOD) and catalase (CAT) enzyme activities. Additionally, SeNPs stimulated the glutathione (GSH-GSSG) cycle in A. flavus TL-F3, elevating glutathione peroxidase (GPX) and glutathione reductase (GR) activity by 17.2% and 23.94%, respectively, and increasing reduced glutathione (GSH) content by 18.59%, and decreasing the GSH/GSSG ratio, thereby effectively alleviating Cu2+ toxicity. Fourier transform infrared spectroscopy indicated that surface functional groups of A. flavus TL-F3, including carboxylic acid, alcohol, phenol, and phosphate/sulfate functional groups, might bind with Cu2+, enhancing its tolerance to Cu2+. This study enriches the theoretical knowledge of microorganism-heavy metal interactions and provides deeper insights into microbial heavy metal resistance mechanisms.