Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202506084
Groundwater is a vital drinking and irrigation source in the loess regions of northwestern China. In Guyuan, a densely populated area in southern Ningxia, systematic assessments of groundwater pollution risks are lacking. This study collected 60 groundwater samples and employed the Nemerow index, heavy metal pollution index (HPI), and health risk assessment models to evaluate pollution levels and health risks of eight elements including Cr, As, and Hg. Results show that the groundwater is generally Class IV quality, with a mean TDS of 1350.9 mg·L−1. Average concentrations of As, Cr, and Mn are 4.39, 29.87, and 45.77 μg·L−1, respectively. The Nemerow index indicates moderate pollution. The mean HPI is 10.56, but a local sample (PS1-51-下) reaches 36.15, indicating severe pollution. Health risk assessment reveals that carcinogenic risks from Cr and As for adults and children are 8.037×10−6 a−1 and 3.863×10−6 a−1, respectively, below US EPA limits but above recommended levels by Swedish and Dutch agencies, with children at higher risk. Hydrogen and oxygen isotopes and principal component analysis suggest that groundwater is primarily recharged by atmospheric precipitation. Cr, Zn, and Mn mainly originate from regional copper ore belts, coal mining, and agricultural activities. This study fills a gap in multidimensional groundwater assessment in populated loess areas, identifies pollution characteristics distinct from typical loess regions, and provides a scientific basis for regional water resource risk management and sustainable development.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3819-7
Selective solar-driven aerobic oxidation of biomass derivatives into valuable chemicals under ambient conditions is pivotal for sustainable chemical manufacturing but faces challenges from the conflict between O2 activation kinetics and selective C–H bond cleavage. This work demonstrates a spatial decoupling strategy in a precisely-engineered 2D/2D g-C3N4/ZnIn2S4 architecture, where ZnIn2S4 domains selectively activate O2, while adjacent g-C3N4 modulates electron transfer to O2 and tailors 5-hydroxymethylfurfural (HMF) binding configuration for selective C–H bond cleavage. This enables efficient selective conversion of HMF to 2,5-diformylfuran (DFF) via ambient aerobic photooxidation. When used alone, ZnIn2S4 produces mixed reactive oxygen species (·O2−/·OH) due to uncontrolled electron transfer during O2 activation. In-situ spectroscopy, Kelvin probe force microscopy (KPFM) and density functional theory (DFT) calculations demonstrate that the 2D/2D heterojunction, driven by its directed electric field, selectively activates O2 into ·O2− at ZnIn2S4 domains while suppressing ·OH generation by moderate electron transfer, mitigating over-oxidation. Adjacent g-C3N4 domains precisely anchor HMF via –OH group interactions, steering selective DFF formation. This spatial decoupling achieves a remarkable HMF-to-DFF photo-conversion rate of 1517.5 μmol g−1 h−1 with 99.4% selectivity under ambient air, outperforming many reported state-of-the-art catalysts and maintaining durable cycling performance. The work establishes a spatial decoupling principle to overcome O2 activation kinetics and site competition thermodynamics, paving the way for advanced catalyst design for sustainable energy and the environment.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.3724/2097-213X.2025.JFCT.0031
The high-temperature behavior of biomass ash critically influences gasifier operational efficiency. This study investigates the differential high-temperature behaviors of corn straw ash (CSA) and wheat straw ash (WSA) using an intelligent ash fusion analyzer, high-temperature rotating viscometer, X-ray diffraction (XRD), SEM-EDS, and FactSage thermodynamic simulations. Both ashes contain high K2O (>30%) and exhibit flow temperatures below 1300 °C. Despite higher K2O and lower SiO2, CSA exhibits a higher flow temperature (1241 °C) than WSA, attributed to elevated CaO (10.39%) and MgO (7.33%) that promote formation of high-melting silicates (K2MgSiO4, K2Ca2Si2O7, CaSiO3). In contrast, WSA with lower CaO (4.92%) and MgO (2.82%) tends to form low-melting potassium silicates. At high temperatures, both slags are typical crystalline slags, with viscosity rising sharply below a critical temperature. For CSA, rapid nucleation and coarsening of silicate crystals (e.g., KAlSiO4 grain size increases from 20.5 nm at 1350 °C to 192.9 nm at 1050 °C) cause abrupt viscosity increase. For WSA, a high P2O5 content (10.05%) induces a 'chemical dilution effect', leading to persistent KAlSiO4 during cooling and elevated viscosity, especially at the final cooling stage. This study elucidates how ash chemical composition governs high-temperature phase equilibrium and non-equilibrium kinetics, thereby macroscopically affecting ash fusion and rheological behavior, providing a theoretical basis for deeper understanding of biomass ash high-temperature characteristics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3851-3
Aqueous zinc-ion batteries (AZIBs) face critical challenges from zinc anode instability, including corrosion, hydrogen evolution reaction (HER), parasitic byproduct formation, and uncontrolled dendrite growth. To address these issues, we developed a multifunctional cerium-based metal-organic framework (Ce-MOF) coating for zinc anodes. The coating features an ordered porous structure and inherent properties that mitigate HER, suppress side reactions, and inhibit dendrite formation. Symmetric cells using Ce-MOF/Zn demonstrated exceptional cycling stability for over 2060 h at 0.5 mA cm−2 with a low hysteresis polarization of 26 mV. In full cells with an I2@AC cathode, the Ce-MOF/Zn||I2@AC achieved outstanding cycling stability of 28,550 cycles at 5 A g−1, with 91% capacity retention (109.6 mAh g−1). Through integrated characterization employing in-situ optical microscopy, ex-situ XRD, SEM, and DFT calculations, we elucidated the multifunctional mechanism: the Ce-MOF coating facilitates preferential (002)-oriented Zn deposition to suppress dendrites, reduces Zn2+ desolvation energy to enhance deposition kinetics, and modulates interfacial chemistry to mitigate HER and corrosion. This work establishes Ce-MOF coatings as a simple yet powerful strategy for developing high-performance zinc anodes, providing critical insights for advancing practical AZIB technologies.