Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202509080
Plastic pollution poses a global environmental challenge, and developing efficient, low-cost pyrolysis catalysts is crucial for resource recovery from plastic waste. This study investigates ex-situ catalytic pyrolysis of low-density polyethylene (LDPE) over ZSM-5 (Si/Al = 25) modified with Zn and Fe at loadings of 5% and 10% via impregnation. Catalysts were characterized by XRD, FT-IR, XPS, SEM, TEM, and BET. TGA was used to assess thermal behavior, and catalytic pyrolysis experiments were conducted in a tube furnace at 450 °C, with product analysis by GC-MS. Results show that metal incorporation preserved the ZSM-5 framework while modifying acid site distribution and surface morphology, enhancing cracking and dehydrogenation. All modified catalysts increased light gasoline-range hydrocarbon yield and reduced heavy fractions compared to non-catalytic runs. Among them, 10% Zn/ZSM-5 exhibited the best performance, boosting light gasoline hydrocarbons to 74.77%, approximately three times that of the non-catalytic case, significantly improving oil quality. This study demonstrates the potential of low-cost metal-modified zeolites for efficient and economical plastic waste pyrolysis.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3810-y
Amorphous metal-organic frameworks (aMOFs), with abundant defects and unsaturated coordination sites, are ideal precursors for investigating electrocatalytic reconstruction mechanisms. However, systematic understanding of how different modulation strategies affect reconstruction pathways and final active species remains lacking. Here, an amorphous MOF constructed from 3,4,9,10-pyrene-tetracarboxylic acid (PTA) serves as a controllable precursor to compare doping and alloying effects on structural reconstruction and oxygen evolution reaction (OER) performance. Doping promotes preferential reconstruction into Fe-rich (oxy)hydroxides with more exposed active sites, whereas alloying yields Fe-Co mixed (oxy)hydroxides with limited site exposure. The doped system FeCo0.05-PTA exhibits outstanding OER activity in alkaline conditions, with overpotentials of 208 and 248 mV at 50 and 100 mA cm−2, respectively, and a low Tafel slope of 36.2 mV dec−1. In situ Fourier transform infrared spectroscopy (FTIR) captures the OOH* intermediate, confirming the adsorbate evolution mechanism. Density functional theory (DFT) calculations show the doped system has the lowest free-energy barrier (ΔG = 0.59 eV) at the rate-determining step. This study underscores the decisive role of precursor design, elucidates distinct effects of doping and alloying on reconstruction pathways and final properties of amorphous MOF-derived (oxy)hydroxides, and provides insights for designing related electrocatalysts.
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.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025040705
Chromium is a common environmental metal pollutant. Shewanella oneidensis MR-1 can generate extracellular electrons, facilitating the reduction of Cr(VI) to Cr(III), thereby mitigating its toxicity. Both biochar and electroactive dissolved organic matter (e-DOM) regulate extracellular electron transfer during Cr(VI) bioreduction. In practice, surface DOM on biochar can detach and enter the environment, while the biochar matrix (BCM) remains the predominant form and coexists with e-DOM. However, the combined effects of BCM and e-DOM on microbial Cr(VI) removal are unclear. This study investigated the individual and combined impacts of biochar matrix and AQDS (a model e-DOM) on Cr(VI) reduction by S. oneidensis MR-1. Results showed that biochar matrix or AQDS alone promoted Cr(VI) removal, primarily by accelerating electron transfer during the fast reduction phase. However, when both were added, an antagonistic effect was observed, attributed to increased repulsive forces between the biochar matrix-AQDS complex and the bacterial cells, which inhibited electron transfer to Cr(VI). This research elucidates the electrochemical interactions between biochar matrix and e-DOM, providing a theoretical basis for biochar applications in environmental remediation and risk assessment.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4029-4
Chemical sensing technology is pivotal in modern industry and daily life, with sensor performance critically reliant on nanomaterials. While sensors based on traditional nanomaterials, such as inorganic semiconductors and organic conductive polymers, have achieved commercialization, they face persistent challenges. As an emerging subclass, conductive metal-organic frameworks (c-MOFs) not only inherit the core advantages of traditional MOFs—high specific surface area, porosity, and tunable composition/structure—but also offer adjustable electrical conductivity, rendering them ideal for sensing applications. This review systematically elucidates the construction and properties of c-MOFs across microscopic crystalline and macroscopic micro-nano structural scales. Special emphasis is placed on the structural design and regulation of c-MOFs for analytical sensing, and the intrinsic structure-performance relationship is clarified to achieve higher sensitivity, selectivity, response speed, and long-term stability, as well as other performance metrics. Finally, we comprehensively summarize the typical applications of c-MOFs-based sensors, covering environmental and safety monitoring, photoelectric detection, and health monitoring and diagnosis. At the same time, the key challenges existing in this field, such as the controllable preparation of high-quality single-crystal materials, the theoretical analysis of intrinsic electrically conductive mechanisms, and the balance between macroscopic material stability and the processing performance of devices, were evaluated. The future research directions should focus on developing new ligands and metal combinations to optimize the band structure, deepening the exploration of the mechanisms of emerging physical effects such as piezoelectricity, and promoting the integration and application of materials in practical scenarios such as flexible electronics and wearable devices.