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.0254-6108.2025031302
Trifluoropropylmethylsiloxanes (D3F and D4F) are emerging contaminants whose environmental behavior remains poorly understood. This study investigated their occurrence, bioaccumulation, and elimination in sediments and mollusks collected from 60 sites across 12 coastal cities along Bohai Bay, China. Concentrations in sediments ranged from <LOD to 17.1 ng/g dry weight (dw) with a detection frequency of 30% and a mean of 5.6 ng/g dw. In mollusks, concentrations ranged from <LOD to 20.2 ng/g wet weight (ww) with a detection frequency of 21.7% and a mean of 4.1 ng/g ww. Compared with cyclic dimethylsiloxanes (D4, D5, D6), trifluoropropylmethylsiloxanes exhibited 1–2 orders of magnitude lower concentrations and 1.4–2.2 times lower biota-sediment accumulation factors (BSAF: 0.67 for D3F, 0.61 for D4F). However, from 2017 to 2023, trifluoropropylmethylsiloxanes showed higher annual accumulation rates in sediments (21.5%) and mollusks (32.8%) than dimethylsiloxanes (10.2% and 6.7%, respectively). This discrepancy is attributed to their higher usage growth, stronger sorption (lg KOC: 6.77 for D3F, 8.81 for D4F vs. 4.22–5.99 for D4–D6), and slower elimination in mollusks (half-lives: 11.1 d for D3F, 20.1 d for trans-D4Fa vs. 5.4–8.6 d for D4–D6). The primary degradation product, methyl(3,3,3-trifluoropropyl)silanediol, was detected in sediments (mean 15.7 ng/g dw, detection frequency 33.3%) and mollusks (mean 31.2 ng/g ww, detection frequency 33.3%). Its accumulation rate in mollusks was 1.4 times faster than in sediments, suggesting its potential as an exposure indicator. These findings highlight distinct environmental behaviors of trifluoropropylmethylsiloxanes, necessitating further monitoring and risk assessment.
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.