SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4412-y
GeTe-based thermoelectric materials are promising lead-free alternatives to PbTe, but their intrinsically high Ge vacancy concentration (~10^21 cm^-3) leads to excessive carrier density and degraded Seebeck coefficient. This study integrates resonant levels (RLs) via In doping and local van der Waals gaps via Sb/Bi alloying to decouple electron and phonon transport. The optimal composition Ge0.91Sb0.04Bi0.04In0.01Te exhibits a Seebeck coefficient of ~287.31 μV K^-1 at 323 K, more than double that of the In-free sample (~102.28 μV K^-1). The peak figure of merit zT reaches ~1.8 at 723 K, with an average zT of ~1.0 over 323–723 K. Vickers hardness is enhanced to ~224 HV, a ~93% improvement over pristine GeTe (~116 HV). X-ray diffraction reveals a structural evolution toward a pseudo-cubic phase with increasing In content, and the (202) peak shifts to lower angles, indicating lattice expansion. These results demonstrate that synergistic RLs and van der Waals gaps effectively optimize carrier concentration and suppress thermal conductivity, offering a viable route for high-performance, mechanically robust GeTe thermoelectrics.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202507085
This study investigates the spatiotemporal differentiation of suspended particulate matter (SPM) characteristics, sources, and their impacts on water quality between the Middle Route (closed artificial channel) and East Route (open natural water system) of the South-to-North Water Diversion Project. Thirty sampling sites (13 on the Middle Route, 17 on the East Route) were established, and samples were collected during dry and wet seasons. Water quality parameters and SPM characteristics were analyzed, including particle size distribution, total suspended solids (TSS), chlorophyll a, and stable carbon and nitrogen isotopes. Results show that the Middle Route maintains good and stable water quality, with SPM dominated by coarse particles (>63 μm, 61.43%–94.68%), total phosphorus (TP) <0.01 mg·L−1, and a significant positive correlation between chlorophyll a and coarse particles (r=0.60), indicating algal aggregation dominates particle formation. In contrast, the East Route exhibits high and fluctuating nitrogen and phosphorus concentrations, with SPM dominated by fine particles (<20 μm, 51.26%–88.61%), TP ranging from 0.03 to 1.11 mg·L−1, and a positive correlation with fine particles, suggesting significant external inputs. Carbon and nitrogen isotope analysis reveals that Middle Route SPM primarily originates from autochthonous algae (contribution >46.75%), while East Route SPM is influenced by both terrestrial C3 plants and algae. The distinct engineering and management approaches of the two routes lead to significant differences in SPM characteristics and sources, thereby affecting water quality dynamics. The Middle Route requires an 'algal reduction and hydrodynamic optimization' strategy to control algal-derived coarse particle deposition, whereas the East Route benefits from 'retention-sedimentation and wetland purification' to reduce external fine particles and pollutant inputs. This research provides theoretical support and practical guidance for differentiated SPM management in long-distance water diversion systems.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202606015
This study evaluated the sustainability and tissue-specific mechanisms of corn stover as a solid-phase carbon source for nitrate removal from groundwater. Cyclic heterotrophic denitrification experiments were conducted using leaf, stem pith, stem bark, stem node, husk, and mixed tissues as carbon sources. Denitrification efficiency, sustainability, dissolved organic carbon (DOC) release, carbon utilization efficiency, intermediate accumulation, and environmental parameters were systematically assessed. Kinetic modeling, correlation analysis, and structural equation modeling (SEM) were applied to elucidate regulatory mechanisms. Results demonstrated that mixed tissues and husk achieved the highest denitrification efficiency, with nitrate removal rates consistently above 98% across four repeated cycles. Total nitrogen removal reached 39.30 mg/g for mixed tissues and 39.95 mg/g for husk, while byproduct concentrations (NO2-N and NH4-N) remained below 2 mg/L. DOC release profiles indicated stable carbon release and high carbon utilization efficiency (203.99 mg TN/g organic carbon for mixed tissues; 182.41 mg/g for husk). Correlation and SEM analyses revealed that carbon source type indirectly governed total nitrogen removal by modulating DOC release, which subsequently influenced pH, electrical conductivity, and nitrogen transformation pathways. Significant differences among tissues were observed in denitrification efficiency, carbon utilization, and micro-environmental regulation. Mixed tissues and husk emerged as superior carbon sources due to their combined efficiency and stability. However, husk released odorous compounds during operation, posing sensory challenges for practical application. The findings support the potential of corn stover tissues as cost-effective carbon sources for in-situ groundwater nitrate remediation, though further optimization is required for field-scale implementation.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202510029
Low hydrolysis efficiency is a core bottleneck in anaerobic digestion (AD) of lignocellulosic agricultural residues, limiting methane production and resource utilization. This study optimized thermal hydrolysis pretreatment (THP) of corn straw (CS) using response surface methodology (RSM) to enhance methane yield. The optimal conditions were determined as solid-to-liquid ratio of 51.0–57.5 mg·mL−1, pretreatment time of 74–81 min, and temperature of 182.5–197.5 °C. Under the optimal combination (52.3 mg·mL−1, 78.4 min, 191 °C), cumulative methane yield increased from 218.0 to 362.9 mL·g−1 VS, a 66.7% improvement over untreated CS. Characterization via XRD, FTIR, and SEM revealed that THP disrupted the lignocellulosic structure, reducing lignin content from 21.5% to 8.3% and crystallinity index (CrI) from 70.83% to 61.95%. Inhibitory derivatives generated during THP included furfural (1.69 mg·mL−1), 5-methylfurfural (2.44 mg·mL−1), and phenol (23.14 mg·L−1), with a theoretical combined inhibition rate of 7.26%. The promotion effect on methane production (66.7%) far exceeded the theoretical inhibition (7.26%), indicating that THP under optimized conditions is effective and environmentally controllable. This study provides a systematic framework for optimizing THP parameters to maximize methane production from agricultural residues.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202608003
The transition of municipal wastewater treatment from energy-intensive aerobic processes to energy-recovering anaerobic technologies is critical for achieving carbon neutrality. However, anaerobic treatment of low-strength wastewater faces operational challenges, especially after prolonged shutdowns and under low-temperature stress. This study investigated the recovery and performance of a pilot-scale anaerobic filter (AF) packed with volcanic rock media (effective volume 240 L) treating actual municipal wastewater. After a 234-day starvation period, the AF recovered within 63 days by extending hydraulic retention time from 8 to 12 hours, achieving total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) removal amounts of 58.6 mg/L and 21.5 mg/L, respectively. Following 100 days of low-temperature operation (influent temperature dropped to 11.7 °C), TCOD and SCOD removal amounts remained at 54.6 mg/L and 28.6 mg/L, respectively. Although methane production volume decreased, the specific methane yield was not significantly affected (0.276 L CH4/g TCODre during recovery vs. 0.244 L CH4/g TCODre under low temperature). Mechanistic analysis revealed that increased protein secretion in extracellular polymeric substances (EPS) was crucial for resistance to low-temperature stress, with protein content negatively correlated with temperature. Microbial community analysis showed that functional populations recovered in the order of hydrolytic acidogens, hydrogen-producing acetogens, and methanogens. Methanobacterium dominated after starvation, while Methanosaeta became dominant after low-temperature exposure due to its high affinity for acetate. Carbon footprint accounting indicated that recovering dissolved methane and coupling with nitrate-dependent methane oxidation is the optimal strategy for carbon reduction.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.1016/S1872-5813(26)60663-9
The catalytic hydrogenation of biomass-derived dimethyl succinate (DMS) to 1,4-butanediol (BDO) is a pivotal route for producing high-value C4 chemicals in green chemistry. Cu/SiO2 catalysts are known for high selectivity in hydrogenating ester groups, with performance correlated to copper species microstructure. Although calcination critically defines this active structure, systematic influence of calcination atmosphere remains underexplored. Here, Cu/SiO2 catalysts were prepared via urea-assisted hydrothermal method and calcined under different atmospheres to elucidate effects on physicochemical properties and hydrogenation performance. Comprehensive characterization (N2 physisorption, FT-IR, H2-TPR, XRD, TEM, N2O pulse chemisorption, XPS, NH3-TPD) revealed that calcination atmosphere profoundly alters metal-support interaction, regulating dispersion and chemical state of copper species. Specifically, air calcination promoted stronger metal-support interaction, enhancing copper dispersion and increasing proportion of key active Cu+ species. Consequently, air-calcined catalyst achieved 92.37% DMS conversion and 64.15% BDO yield under optimized conditions (210 °C, 5.0 MPa, WHSV 0.6 h−1, H2/DMS molar ratio 100). This work underscores calcination atmosphere engineering as potent strategy for optimizing metal-support interactions in heterogeneous catalysts for efficient hydrogenation.