Oxalate modification represents an eco-efficient strategy to address nanoparticle aggregation in nano zero-valent iron (nZVI) systems while synergistically enhancing U (VI) removal through coupled adsorption-reduction mechanisms. This study synthesized sodium oxalate-modified nZVI (OA-nZVI) via liquid-phase reduction. The oxalate coating effectively suppressed particle agglomeration induced by magnetic interactions and van der Waals forces. Systematic investigations were conducted to elucidate the morphological evolution of nZVI post-modification and its mechanistic behavior in uranium-contaminated groundwater remediation. Characterization revealed that OA-nZVI exhibited a transformation from irregular spherical particles to well-defined spherical geometries, accompanied by an increased Fe0 content in the mineral phase. Under optimized conditions (pH=5, 25 ℃, dosage=0.5 g/L), OA-nZVI demonstrated exceptional U (VI) removal efficiency. The enhanced performance originates from synergistic interactions: Carboxyl groups on oxalate ligands facilitated uranyl adsorption via surface complexation, and the Fe0 core mediated electron transfer for U (VI) reduction to U (IV). Subsequent oxidation generated goethite (α-FeOOH), which further immobilized uranium through hydroxyl coordination. The removal kinetics adhered to a pseudo-second-order model, while equilibrium data fitted the Langmuir isotherm, yielding a maximum theoretical adsorption capacity of 196.31 mg/g. Notably, competitive ions (Al3+and ) exhibited significant inhibitory effects, necessitating consideration in field applications.This work provides critical insights for developing advanced uranium remediation materials. Future research directions should prioritize: Evaluating material stability under complex hydrogeochemical conditions (e.g., high salinity with coexisting
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), pH=3~10, and humic acid presence), and validating performance through dynamic column experiments simulating groundwater flow regimes and ion exchange processes. These investigations will bridge the gap between laboratory-scale achievements and practical engineering applications.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |