SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3407-0
Grain boundary (GB) engineering has emerged as a promising strategy to enhance the near-room-temperature performance of Mg3(Sb,Bi)2-based thermoelectric materials, yet effective control of Mg distribution at GBs remains a significant challenge. Here, we report a novel approach to achieve targeted Mg segregation at GBs through strategic Ag incorporation in Mg3.3Sb0.5Bi1.497Te0.003. Through comprehensive microstructural characterization and first-principles calculations, we demonstrate that Ag preferentially segregates at GBs, forming Mg-rich MgAg alloy phases while maintaining limited solid solubility within the matrix. This unique GB architecture simultaneously optimizes multiple thermoelectric parameters: the Mg-rich GB regions significantly provide efficient carrier transport channels and enhance carrier mobility, while the MgAg phases and lattice disorders effectively scatter phonons without disrupting electron transport. Consequently, the optimized composition (x = 0.01) exhibits a remarkable enhancement in power factor at 300 K and maintains an average ZT of ~1.0 across 300–400 K. The material also demonstrates excellent mechanical properties and thermal stability, making it particularly suitable for near-room-temperature applications. Our findings not only establish an effective strategy for GB engineering in Mg3(Sb,Bi)2 systems but also provide valuable insights into the rational design of high-performance thermoelectric materials through interface modification.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3800-7
Two-dimensional van der Waals (vdW) crystals, stacked via atomically thin layers, exhibit rich functionalities and tunable stacking orders. Their mechanical behaviors are crucial for flexible and miniature electronics. While some vdW crystals show superior plasticity, the mechanical properties of SnS2 bulk crystals remain largely unexplored. Here, we synthesize high-quality SnS2 crystals via the Bridgman method and comprehensively investigate their mechanical properties. SnS2 bulk crystals exhibit remarkable plasticity and softness: bending and compression strains exceed 20% and 45%, respectively, without fracture, while tensile fracture strains reach up to ~12% (range 9%–16%). Scanning/transmission electron microscopy reveals multiple deformation units, including layer segments, interlayer/cross-layer slip, twisting, and twinning-like structures. These units provide multiple pathways to release strain energy, promoting plasticity. Alongside weak interlayer vdW interactions, relatively ionic and weak intralayer Sn–S bonds contribute to the softness. This work fills the knowledge gap on SnS2 mechanical properties, advancing its processing and application in diverse electronic devices. Further studies may focus on balancing plasticity and strength by tuning microstructure to activate but confine deformation units.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202605024
The refined quantification of carbon footprint in engineering construction projects is critical for formulating targeted carbon reduction strategies during the materialization phase. This study integrates material flow analysis (MFA) with the emission factor method to establish a panoramic carbon flow model for engineering projects. Construction activities are categorized into processing and construction, and office and daily operations, clarifying material and carbon flow relationships within the system boundary and with external systems. Empirical analysis was conducted on the Hejiawan Bridge of Section 11 of the Xiyu High-Speed Railway. Results show that the total carbon flow amounts to 27,482,432.11 kg CO2eq, with direct carbon flow (fuel oil, gasoline) accounting for 7.6% and indirect carbon flow (products, transportation, electricity) accounting for 92.4%. From the material flow perspective, the total carbon flow comprises product carbon flow (72.88%), resource and energy carbon flow (25.73%), transportation carbon flow (1.04%), waste carbon flow (0.35%), and service carbon flow (0.01%). In terms of activity scope, construction-related carbon flow accounts for 99.17%, while office and daily operations account for 0.46%. Two indicators, material consumption carbon flow rate and energy consumption carbon flow rate, are proposed for the first time. Comparative analysis of five girder bridges reveals that the Hejiawan Bridge has a material consumption carbon flow rate of 3.91 kg CO2eq/kg, ranking highest among similar bridges, while its energy consumption carbon flow rate is 13.40 kg CO2eq/kg ec, at a medium level. The assessment indicates relatively high material consumption, suggesting potential for carbon reduction through structural and geological optimization.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202510084
The rapid expansion of lithium battery industries has elevated lithium resources to strategic importance, yet lithium extraction generates 8–10 tons of slag per ton of lithium salt, with complex heavy metal content and high leaching risks. This study improves conventional alkali activation by employing a composite activator and multi-stage thermal assistance to achieve self-solidification of lithium slag, simultaneously immobilizing multiple heavy metals while producing high-strength materials. Under full slag conditions, the mechanical strength of solidified materials ranged from 3.48 to 8.25 MPa; after optimization, strength increased by 137.07%. Average immobilization rates for various heavy metals rose from 97.26% to 99.77%. In simulated acidic, alkaline, neutral, high-salt, acid rain, and leachate environments, efficient immobilization was maintained, with leachate concentrations below regulatory limits. The improved activator and thermal process reduced structural defects, promoted formation of the key Si-O-Al framework, and ensured structural integrity, enhancing both mechanical strength and heavy metal immobilization. The cost of slag solidification was approximately 185–200 CNY per ton, significantly lower than conventional methods, with low energy consumption, no high-temperature calcination, and reduced equipment and reagent requirements, supporting scalability.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202510060
Wastewater treatment plant (WWTP) effluent is a significant pathway for emerging contaminants (ECs) to enter natural water bodies. This study investigated the removal of ECs by two field-scale gravel-based constructed wetlands: a horizontal subsurface flow constructed wetland (QL-CW) and a surface flow constructed wetland (BL-CW), both treating actual WWTP effluent. The influence of operation mode and wetland plant type on EC removal was examined. Using liquid chromatography-mass spectrometry, principal component analysis, and ecological risk assessment, the removal efficiencies and mechanisms for various ECs were explored. In QL-CW, biodegradation was more pronounced, particularly via ammonia-oxidizing bacteria co-metabolism, favoring ECs with benzyl, secondary amine, secondary amide, tertiary amide, halogenated, and carboxyl functional groups. In BL-CW, electrostatic attraction and hydrophobic interactions were more significant, with plant and root-microorganism uptake and adsorption playing key roles. Surface flow mode achieved significantly higher removal of antibiotics (45.3% vs. 34.1%) compared to horizontal subsurface flow, while no significant differences were observed for non-antibiotic pharmaceuticals (66.6% vs. 64.4%) and pesticides (49.8% vs. 34.2%). Planting Cyperus alternifolius (windmill grass) was more beneficial for antibiotic removal (43.6% vs. 30.1%) than planting Ipomoea aquatica (water spinach). The wetlands effectively reduced the ecological risks of most ECs to marginal levels. This study provides insights into the deep treatment of ECs in WWTP effluent by constructed wetlands.