Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025112603
The cycloaddition of carbon dioxide (CO2) to epoxides (CCE) is a 100% atom-economical transformation yielding cyclic carbonates, which are valuable chemical products. This reaction valorizes CO2 as a carbon feedstock, mitigating the greenhouse effect and aligning with carbon neutrality goals. Conventional covalent organic framework (COF) catalysts often require co-catalysts to achieve high efficiency. To address this, we designed and prepared a series of ionic COFs, denoted EB-BT(nOH), that simultaneously incorporate acid (hydroxyl), base (nitrogen), and nucleophilic bromide (Br−) functionalities. These materials efficiently catalyze the CCE reaction without any co-catalyst. Among them, EB-BT(OH) exhibited the highest catalytic activity, achieving a 99% yield of the target product at 120 °C and 2.0 MPa CO2 pressure. By systematically varying the hydroxyl content in the COF backbone, we investigated the critical role of hydrogen bond donors (HBDs) in the CCE reaction. This work provides new design principles for COF-based catalysts for CCE, eliminating the need for co-catalysts and enhancing process sustainability.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025030302
A novel core-shell composite adsorbent, C18-SiO2@C, was synthesized for the determination of five phthalates in food samples. The adsorbent was prepared by assembling hexamethylcyclotrisiloxane (D3) into γ-cyclodextrin (γ-CD) cavities via saturated solution method, followed by hydrothermal oxidation to form SiO2@C, and subsequent C18 modification on the inner SiO2 core. The outer hydrophilic amorphous carbon shell enables effective extraction, while the inner C18 layer provides hydrophobic interactions. Using tip-based solid-phase microextraction (SPME), the adsorbent (10 mg) efficiently enriched phthalates from water, milk, and cola. Under optimized conditions (pH, eluent type/volume, sample volume, salt concentration), the method coupled with GC/MS exhibited linearity in the range of 0.5–10 ng·mL−1 (R² > 0.99), limits of detection (S/N ≥ 3) of 0.04–0.15 μg·L−1, and spiked recoveries of 74%–100% (RSD 1.32%–3.49%). For real samples, recoveries were 84.6%–102.3% for tap water, 80.7%–104.6% for cola, and 80.2%–101.4% for milk. The method offers simplicity, rapidity, low sample consumption, high enrichment efficiency, and strong matrix interference resistance, demonstrating significant potential for trace phthalate monitoring in foods.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025030404
The photoelectrocatalytic degradation of seven sulfonamide antibiotics—sulfathiazole (STZ), sulfadiazine (SDZ), sulfisoxazole (SIA), sulfamethoxazole (SMZ), sulfapyridine (SPD), sulfadimidine (SMT), and sulfaguanidine (SG)—was investigated using a bismuth vanadate-loaded titanium dioxide array (BiVO4/TiO2) as the anode under visible light irradiation. Systematic evaluation of BiVO4 loading, solution pH, current density, electrolyte type, and electrolyte concentration revealed optimal conditions of 50 mmol·L−1 Na2SO4, a current density of 1.67 mA·cm−2, and pH 2. Under these conditions, STZ removal and total organic carbon (TOC) removal reached 95.7% and 76.7%, respectively. Removal efficiencies for SDZ, SIA, SMZ, SPD, SMT, and SG were 94.9%, 80.9%, 79.1%, 57.7%, 52.3%, and 52.0%, with TOC removal ranging from 50% to 76.7%. Quenching experiments and electron paramagnetic resonance (EPR) identified hydroxyl radicals (·OH), singlet oxygen (1O2), and sulfate radicals (SO4−·) as dominant reactive species. The BiVO4/TiO2 composite exhibited a valence band edge at EVB = 2.775 V vs. RHE, enabling oxidation of H2O, OH−, and SO4^2− to generate these radicals. The heterostructure narrowed the bandgap to 2.12 eV and enhanced visible light response, facilitating efficient charge separation and transfer. Degradation pathways involved oxidation of aniline moieties to nitro groups, followed by hydroxylation and cleavage of S–N, N–C, or S–C bonds, ultimately mineralizing to CO2, H2O, SO4^2−, and NO3−. The system demonstrated high stability and catalytic efficiency across acidic and alkaline conditions, offering a promising approach for antibiotic removal from environmental waters.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025042101
Chloropyridine compounds, widely used as pesticide intermediates in China, pose significant risks to aquatic ecosystems and human health due to their high toxicity, persistence, and frequent detection in water bodies. This study addresses the removal of 3,4,5,6-tetrachloropyridine-2-carboxylic acid (TCPA), a representative chloropyridine contaminant, using a novel composite material. Biochar-supported zero-valent iron/iron carbide composites (SL-FeC2O4-800 °C) were synthesized via a high-temperature carbothermal process, employing activated sludge as the carbon source and ferrous oxalate (FeC2O4) as the iron precursor. The composite exhibited rapid and efficient TCPA degradation across a wide pH range (3–9), achieving 98% removal within 2 minutes. Mechanistic studies using scavenging experiments revealed that TCPA removal proceeds through synergistic pathways: adsorption onto biochar, direct reduction by zero-valent iron, and oxidation by reactive oxygen species (ROS) generated via oxygen activation. Surface-bound iron species were identified as critical for ROS formation. The material demonstrated reusability over five cycles, with degradation efficiencies decreasing from 98.54% to 40.36%, indicating gradual deactivation due to iron consumption and surface passivation. This work not only provides an efficient and environmentally sustainable method for removing persistent and highly toxic pollutants like TCPA but also offers a novel strategy for sludge resource utilization. The low-cost raw materials, simple preparation, and high activity position this composite as a promising candidate for industrial wastewater treatment, particularly in pesticide manufacturing effluents.