Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2024083002
Selenium (Se) is an essential trace element for human health, and dietary intake through Se-rich crops is the primary route. However, total soil Se content does not directly reflect the bioavailability to plants, which depends largely on soil available Se. This study, conducted in Shipai Town, Longshan County, Hunan Province, used 1:50,000 land quality geochemical survey data to investigate factors influencing the Se bioaccumulation coefficient in maize kernels. Soil pH, CaO, and MgO were identified as significantly positively correlated with the bioaccumulation coefficient and were selected as proxies for soil available Se. A random forest (RF) model was developed to predict maize grain Se content and assess the feasibility of cultivating Se-rich maize in low-Se farmland. Results showed that although soil Se was deficient, 53.64% of maize grain samples met the Se-rich product standard (0.02–0.30 mg·kg−1). Compared with multiple linear regression, the RF model exhibited higher accuracy and reliability. The RF model predicted that 40.91% of farmland in the study area is suitable for natural Se-rich maize cultivation, representing a 25.86% increase over the area identified by soil total Se alone. This study provides a novel methodological framework for planting natural Se-rich maize in Se-deficient regions, validating the potential for such cultivation.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202507088
Methanol is highly biodegradable, yet its efficient and stable anaerobic treatment is constrained by prolonged microbial adaptation to toxic substances, narrow microbial community structure, and poor sludge granulation. This study applied two functional additives—sodium bicarbonate (NaHCO3) as an inorganic carbon source (IC) and an amino-acid-rich organic functional supplement (FS)—to accelerate the startup of two upflow anaerobic sludge blanket (UASB) reactors. UASB-A received 3,000 mg·L−1 NaHCO3 and 127 mg·L−1 FS, while UASB-B received only 3,000 mg·L−1 NaHCO3. Both additives enabled rapid startup and granulation by shortening hydraulic retention time (HRT) and increasing organic loading rates (4, 6, 9, 15, 20, and 30 g COD·L−1·d−1). Granulation was evidenced by increased total suspended solids (TSS), volatile suspended solids (VSS), and particle size distribution. Microbial community analysis at HRT 0.2 d revealed highest relative abundances of Acetobacterium at 30.2% (UASB-A) and 36.9% (UASB-B). NaHCO3 supplementation enhanced syntrophy between Acetobacterium and the acetoclastic methanogen Methanothrix, while FS significantly increased the abundance of Sporomusa, establishing a novel syntrophic relationship with Methanothrix. These interactions promoted sludge granulation. The study demonstrates that functional additives facilitate rapid startup and granulation in methanol anaerobic treatment, offering a strategy to overcome process bottlenecks.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.3724/2097-213X.2025.JFCT.0035
Iron-based catalysts in CO2/H2 atmospheres undergo dynamic carburization and oxidation phase transitions, complicating active-phase identification and stability control. This study prepared high-purity single-phase χ-Fe5C2 (Hägg carbide) and θ-Fe3C (cementite) via gas-solid carburization, with purity confirmed by XRD and Mössbauer spectroscopy. Fixed-bed reactor tests (H2/CO2 = 1, 0.1 MPa, 270–420 °C), pulse experiments (270 °C), and in situ XRD (10% CO2/He, 340 °C) were employed to investigate catalytic performance and structural evolution in the reverse water-gas shift (RWGS) reaction. Results show that χ-Fe5C2 exhibits higher RWGS activity but is more susceptible to oxidation, whereas θ-Fe3C demonstrates superior oxidation resistance but lower activity. Under RWGS conditions with H2, θ-Fe3C partially transforms into χ-Fe5C2; however, in 10% CO2 atmosphere, both carbides directly oxidize to Fe3O4 without inter-carbide transformation. In situ XRD at 340 °C and 0.1 MPa revealed that χ-Fe5C2 fully oxidizes within 11 h, while θ-Fe3C retains residual phase after 18.3 h, confirming its higher oxidation stability. These findings elucidate the atmosphere-dependent evolution mechanisms of χ-Fe5C2 and θ-Fe3C, providing experimental basis for phase-structure regulation and operational stability optimization in iron-based Fischer-Tropsch and RWGS catalysts.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202607016
Lead (Pb) is a highly toxic heavy metal that poses severe risks to environmental and human health, particularly affecting children's neurological development. This study investigates the adsorption performance and mechanisms of biochars derived from pyrolysis of Napier grass (Pennisetum purpureum), food waste digestate, and their mixtures for Pb²⁺ removal from aqueous solutions. Biochars were prepared at different mass ratios, and the optimal material (HP3SD1-B, Napier grass:digestate = 3:1) exhibited a maximum equilibrium adsorption capacity of 306.45 mg/g and a theoretical Langmuir maximum capacity of 447.62 mg/g, significantly outperforming pure digestate biochar and lower-ratio blends. Adsorption kinetics followed a three-stage profile: rapid liquid-film diffusion (0–180 min), intraparticle diffusion (180–360 min), and equilibrium at 360 min. The adsorption process was well described by the pseudo-second-order kinetic model (R² > 0.99) and the Langmuir isotherm, indicating monolayer chemisorption. Characterization via FTIR, XPS, SEM-EDS, and Zeta potential revealed that Pb²⁺ immobilization occurs primarily through surface precipitation (Pb₃(CO₃)₂(OH)₂ and PbO), complexation with hydroxyl, ether, and aromatic C=C groups, and auxiliary mechanisms including electrostatic attraction and K⁺/Mg²⁺ ion exchange. Optimal adsorption occurred at pH 6, correlating with the point of zero charge (PZC ≈ 2). This study demonstrates that co-pyrolysis of agricultural and organic solid wastes offers a cost-effective, high-performance biochar for heavy metal remediation, aligning with circular economy principles.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025042203
Cadmium (Cd) accumulation in crops is influenced by complex, crop-specific factors, posing challenges for the safe utilization of soils with elevated Cd levels. This study focused on a region with anomalously high soil Cd in northern Longshan County, Hunan Province, China. We systematically collected and analyzed Cd concentrations in the edible parts of lily (Lilium spp.) and maize (Zea mays L.), along with corresponding root-zone soil properties including Cd content, pH, and oxide levels. The bioconcentration factors (BCF-Cd) for lily and maize were compared, and their controlling factors were identified. Using random forest with hyperparameter optimization, optimal predictive models for BCF-Cd were developed for each crop. Results showed that lily BCF-Cd was significantly higher than that of maize. Key factors influencing BCF-Cd in both crops included soil pH, manganese (Mn), organic matter (OM), and the weathering-leaching coefficient (ba). Feature importance analysis identified soil pH as the most critical factor. Based on model predictions, a zoning scheme for safe arable land utilization was proposed to maximize land productivity while ensuring the medicinal safety of lily and food safety of maize. This study provides scientific support for enhancing food security and optimizing land resource use.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4038-8
Fluorescent fibers and textiles that integrate outstanding optical performance with excellent flexibility hold significant promise for wearable applications and the Internet of Things (IoT). However, the poor stability of post-organized phosphor-based fibers and the high-cost, high-precision technology of electroluminescent fibers hinder their widespread adoption. Perovskite materials and organic semiconductors, owing to their high-efficiency, tunable luminescent properties and solution processability, are deliberately employed to fabricate desired fluorescent fibers and textiles via a spinning chemistry strategy. Recent advances have successfully applied these fibers to sensors, information displays, optical communications, and health monitoring. This review provides a comprehensive overview of recent progress in fluorescent fibers and textiles, covering spinning techniques, emitter design, and wearable applications. We highlight key challenges and future research directions in the fine design and synthesis of fluorescent fibers and textiles, as well as their system integration for practical wearable applications. The review emphasizes the potential of spinning chemistry to enable scalable production of robust, high-performance luminescent fibers, addressing stability and cost barriers. We discuss the use of metal halide perovskite quantum dots (PQDs) with high photoluminescence quantum yields (PLQY) and tunable emission, and organic semiconductor emitters with tailored molecular structures, as promising building blocks. The integration of these materials into fibers via spinning chemistry offers a facile, efficient, and controlled strategy, leading to ultra-stable CsPbX3 (X = Cl, Br, I) perovskite filaments with a PLQY of 24.5% and stretchability up to 2400%. The review concludes by outlining future research directions, including the development of lead-free perovskites and self-healing materials, to enhance stability and safety for commercial wearable technologies.