Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025091203
The persistence of tetracycline (TC) in aquatic environments poses significant ecological risks. This study developed a homogeneous reaction system based on carboxylated Fe2+ enhanced peroxymonosulfate (PMS) activation, using citric acid (CA) as a ligand. Carboxylation improved Fe2+ stability and catalytic activity, while solid PMS served as the oxidant, circumventing issues of traditional Fenton processes such as H2O2 instability, complex heterogeneous catalyst preparation, high disposal costs, and toxic metal leaching. The acidic pretreatment enabled by CA inhibited Fe2+ oxidation and promoted sustained PMS activation without external energy input. Under optimized conditions (TC 5 mg·L−1, Fe2+ 0.02 mmol·L−1, CA 0.001 mmol·L−1, PMS 2 mmol·L−1), 88.80% TC degradation was achieved within 60 min. Mechanistic studies revealed that CA protected Fe2+ active sites via carboxyl coordination, facilitating continuous generation of reactive species, including singlet oxygen (1O2) and sulfate radicals (SO4•−). 1O2 was the dominant species (50.5% contribution), followed by SO4•− (35.7%), synergistically driving efficient TC degradation while significantly reducing iron sludge production. Phytotoxicity assays confirmed that treated water exhibited no significant toxicity to wheat seedlings (P > 0.05), indicating effective ecological risk elimination. This work provides a low-energy, operationally simple, and environmentally friendly technology for antibiotic-contaminated water treatment, with promising practical application potential.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202605003
Dark fermentation offers a sustainable route for hydrogen production, yet its yield is often limited by inefficient electron transfer and low microbial metabolic activity. This study engineered a mixed microbial biohybrid system incorporating Fe2O3 nanoparticles to overcome these bottlenecks. At an optimal Fe2O3 concentration of 300 mg/L (S300), the hydrogen yield reached 2.94 mol H2 per mol glucose, equivalent to 73.5% of the theoretical maximum and 1.59 times higher than the control (S0). Mechanistic analyses revealed that Fe2O3 nanoparticles stimulated microbial metabolism, as evidenced by a 4.09-fold increase in ATP content and a 1.30-fold rise in total protein concentration. Hydrogenase and dehydrogenase activities were enhanced by 24.62% and 63.11%, respectively, while electron transfer system activity increased by 3.44-fold, accompanied by a significant reduction in charge transfer resistance. Notably, the gradual release of Fe2+ ions from Fe2O3 reduction by dissimilatory iron-reducing bacteria (DIRB) was identified as a key factor in stimulating enzyme activity and electron transfer. Microbial community analysis showed that the relative abundance of Clostridium, a key hydrogen-producing genus, increased by 9.75 percentage points to 42.60% in S300. This study demonstrates that Fe2O3-based biohybrids offer a promising strategy to enhance dark fermentation hydrogen production, providing both performance improvements and mechanistic insights into nanomaterial-microbe synergies.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025050601
China's iron and steel industry has undergone comprehensive ultra-low emission transformation, meeting stringent limits for conventional pollutants, yet the fate of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) remains unclear. This study combined field sampling and literature review to analyze PCDD/Fs emission characteristics from sintering, converter, and electric arc furnace processes before and after transformation, and calculated national emissions for 2022. Results demonstrate that ultra-low emission transformation effectively reduces PCDD/Fs emissions. Specifically, emission concentrations decreased by 86.5%, 95.1%, and 66.9% for sintering, converter, and electric arc furnace, respectively, with corresponding emission factors dropping to 0.11, 0.009, and 0.014 μg I-TEQ·t−1 product. Under the transformation scenario, total national emissions were 104 g I-TEQ (uncertainty ±26 g), a 94.9% reduction from the unreformed scenario (2049 ± 763 g I-TEQ). Congener profiles shifted from high-chlorinated dominance to low-chlorinated dominance, while toxicity equivalent distribution remained dominated by 2,3,4,7,8-PeCDF (35%–56%). This study quantifies the co-benefit of PCDD/Fs reduction, providing critical data for updating China's emission inventory and formulating toxicity-oriented control policies.