Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202506005
The escalating generation of medical waste, driven by healthcare expansion and frequent medical activities, poses significant environmental and public health risks. Under the framework of ecological civilization, China is developing a comprehensive policy system for medical waste treatment and disposal, yet the current framework remains nascent and exhibits inconsistencies between national and local policies. This study systematically analyzes the status of national and local policies from 2003 to 2024, collecting 413 policy documents (166 from national ministries and 247 from provincial governments). The analysis examines temporal evolution, regional distribution, and policy focus, alongside the influence of medical waste output, treatment technologies, facility infrastructure, and major epidemic responses. Findings reveal distinct policy phases: initial self-disposal, exploratory management, foundational system building, and rapid development. Regional disparities are pronounced, with eastern coastal areas showing more advanced policies due to greater technical and financial resources. The surge in medical waste, particularly during the COVID-19 pandemic, underscores the need for enhanced regulatory guidance. Non-incineration technologies are gaining traction for their environmental and cost benefits, and facility coverage has improved but remains uneven. The study proposes five policy principles to foster technological innovation and industrial upgrading, ensuring safe medical waste management and environmental protection.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2024112806
Microplastics (MPs) are persistent emerging contaminants ubiquitously distributed in soil-groundwater environments, where their aggregation and transport critically govern pollutant fate and ecological risks. Natural organic matter (NOM), a complex assemblage of organic compounds, interacts with MPs and porous media via hydrogen bonding, π-π interactions, hydrophobic effects, and electrostatic binding, thereby modulating MP surface properties and environmental behavior. This review systematically synthesizes the mechanisms by which NOM influences MP aggregation and transport, with emphasis on the distinct roles of humic substances, proteins, and extracellular polymeric substances (EPS), and their synergistic modulation with solution chemistry (pH, ionic strength, ion type). Additionally, NOM accelerates MP aging and alters surface characteristics, consequently impacting transport capacity. Current research limitations are identified, and future directions are proposed to inform MP pollution risk assessment and management strategies. Key findings indicate that NOM generally enhances MP stability and mobility at low ionic strengths, while high ionic strengths may induce aggregation depending on NOM type and ion valence. Humic substances predominantly increase electrostatic repulsion, whereas proteins and EPS can bridge particles, promoting aggregation. Aging processes, accelerated by NOM photochemical activity, increase surface oxygen functionality and hydrophilicity, further altering transport. The review underscores the need for systematic studies under environmentally relevant conditions to predict MP fate accurately.
The Chinese Journal of Process Engineering•2026•DOI: 10.12034/j.issn.1009-606X.225213
Gas-liquid stirred tanks are widely used in oxidation, hydrogenation, and other chemical processes, where the gas dispersion state directly affects production efficiency. This study systematically investigated the effects of impeller type, impeller installation height, and rotational speed on gas-liquid dispersion in a stirred tank equipped with a porous tube sparger. Two typical impellers, a wide hydrofoil (WH) and a half-elliptical disk turbine (HEDT), were tested at various installation heights (L/D ratios) and gassing rates. The critical rotational speed for complete gas dispersion, agitation power consumption, and overall gas holdup were measured. Results showed that for both impellers, the critical Froude number (Fr) decreased significantly with increasing gas flow number (FlG). Under the same gassing rate, the HEDT impeller generally required a higher critical Fr and greater agitation power for complete dispersion compared to the WH impeller. Relative power demand (RPD) decreased as FlG increased, with a more pronounced decline at higher L/D ratios. At different impeller positions, the RPD of the HEDT impeller was higher than that of the WH impeller, indicating that the HEDT impeller's power was less affected by gas. Notably, the impeller installation height significantly influenced gas holdup and power consumption. When L/D = 0.75, higher gas holdup and lower power consumption were observed. This work provides crucial theoretical and data support for optimizing the design of gas-liquid stirred tanks with gas sparging, offering clear engineering value for enhancing mass transfer efficiency and energy-saving operation in chemical processes.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3856-0
Replacing the kinetically sluggish oxygen evolution reaction (OER) with biomass oxidation at photoanodes offers a cost-effective and energy-efficient route for simultaneous hydrogen production and value-added chemical synthesis in a photoelectrochemical (PEC) cell. Here, titanium-doped hematite nanorods (Hem) decorated with CoNi bimetallic zeolitic imidazolate frameworks (ZIF) were prepared via room-temperature deposition and employed as photoanodes for 5-hydroxymethylfurfural (HMF) oxidation. Using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as a redox mediator in alkaline electrolyte, the CoNi-ZIF/Hem photoanode achieved a photocurrent density of 1.09 mA cm−2 at a low bias of 1.1 V vs. reversible hydrogen electrode (RHE). Experimental results and theoretical calculations reveal that CoNi-ZIF accelerates charge transfer and separation, and enhances TEMPO adsorption on the surface, benefiting PEC TEMPO-mediated HMF oxidation to 2,5-furandicarboxylic acid (FDCA). In a flow-cell reactor under 1 sun illumination, the photoanode achieved ~99% HMF conversion and ~98% FDCA yield within 2 hours. The photoanode also exhibited excellent performance for TEMPO-mediated oxidation of various aldehyde-containing biomass-derived compounds. This work demonstrates a rational design of hematite-based photoanodes for efficient biomass valorization coupled with hydrogen production.
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.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3880-8
Formaldehyde oxidation reaction (FOR) demonstrates significant potential in energy conversion and chemical synthesis, yet developing catalysts for efficient operation at high current densities remains a challenge. Herein, we fabricated a Cu/Cu2O heterostructure nanowire catalyst on copper foam (Cu/Cu2O@CF) via interface engineering and investigated its FOR performance. Electrochemical tests show that Cu/Cu2O@CF exhibits excellent activity: it achieves 100 mA cm−2 at an ultra-low potential of −0.05 V (vs. RHE), outperforming most reported catalysts. Notably, this catalyst overcomes the deactivation limitation of conventional Cu-based catalysts above 0.5 V, maintaining a current density of 735 mA cm−2 at 0.6 V with excellent stability during long-term electrolysis. SCN−-induced Cu0 poisoning experiments confirm that Cu/Cu2O@CF retains a Cu/Cu2O mixed structure at 0.6 V, where Cu0-Cu+ synergy dominates its high activity. Density functional theory (DFT) calculations reveal two key advantages of this structure: it weakens OH− adsorption to avoid active site occupation, and reduces C–H bond cleavage barriers while promoting H* combination into H2. Product analysis shows Faradaic efficiencies for formate and H2 production are both ~100%. When coupled with the hydrogen evolution reaction (HER), the system's hydrogen production energy consumption is as low as 0.57 kWh m−3 H2, much lower than traditional water electrolysis. This work elucidates the regulatory mechanism of interface engineering on the FOR performance of Cu-based catalysts, expands the application of Cu-based heterostructures in high-current FOR, and guides the development of industrial-grade electrocatalysts.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025041904
Non-fentanyl opioids, a subclass of new synthetic opioids (NSOs), have emerged as the fastest-growing category of new psychoactive substances (NPS) globally, driven by regulatory tightening on fentanyl analogs. Their structural diversity, rapid in vivo metabolism, and multiple metabolic pathways complicate detection in biological matrices, posing significant challenges for forensic toxicology and environmental monitoring. Liquid chromatography-mass spectrometry (LC-MS) remains the gold standard for trace-level quantification due to its high sensitivity, specificity, and accuracy. This review systematically examines the classification, toxicological profiles, and metabolic routes of non-fentanyl opioids, including AH-7921, MT-45, U-47700, brorphine, and nitazenes. It critically evaluates sample preparation techniques—solid-phase extraction (SPE), liquid-liquid extraction (LLE), and protein precipitation (PPT)—highlighting their efficiency, recovery rates, and matrix effects. Furthermore, it synthesizes recent advances in LC-MS methodologies, including high-resolution mass spectrometry (HRMS) and tandem mass spectrometry (MS/MS), with emphasis on multiplex detection capabilities, limits of detection (LODs) reaching sub-ng/mL levels, and validation parameters. The review underscores the necessity for continuous analytical innovation to keep pace with emerging NSOs and provides a technical framework for accurate identification in forensic and environmental contexts.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4149-1
Large optical anisotropy is paramount for efficient light manipulation in optoelectronic devices. Van der Waals layered materials, exhibiting large structural contrast between in-plane and out-of-plane directions, are inherently anisotropic in 3D space. However, measurements of their optical constants have been limited to 2D planes. Here, we directly measure reflectance spectra from the edge and basal surfaces of layered MoS2, NbOCl2, and WTe2 crystals to compare out-of-plane and in-plane optical constants in the 500–1000 nm range. Results show that out-of-plane refractive indices are smaller than in-plane values. Out-of-plane extinction coefficients are zero for MoS2 and NbOCl2 but nonzero for WTe2, confirmed by transient reflection spectroscopy. The nonzero extinction in WTe2 arises from symmetry of transition dipole moments and density of states dictated by crystal structure. Out-of-plane optical constants of MoS2 and NbOCl2 exhibit less dispersion than in-plane, whereas WTe2 shows enhanced out-of-plane dispersion around 2.14 eV, attributed to increased optical transition probability from larger density of states. These parameters indicate giant birefringence (>1.8 for MoS2, >0.6 for NbOCl2, >0.5 for WTe2) and linear dichroism (up to 100% for MoS2 and NbOCl2, 40.7% for WTe2) on edge surfaces. Results enable prediction of optical response at arbitrary incidence angles, aiding polarization-related optoelectronic devices.