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| Phosphorus and arsenic adsorption characteristics and migration features in soils from different sites |
| Received:January 12, 2025 |
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| KeyWord:phosphorus;arsenic;soil;adsorption;transport |
| Author Name | Affiliation | E-mail | | QIN Hua | Hanzhong Environmental Monitoring Center Station, Hanzhong 723000, China | | | XU Dongying | College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | | | KANG Runfeng | College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | | | YIN Xianqiang | College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | | | SUN Huimin | College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | sunhuimin@nwsuaf.edu.cn |
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| Abstract: |
| To investigate the adsorption characteristics of phosphorus（P）and arsenic（As）and their migration behaviors in different site soils, batch equilibrium adsorption tests were conducted, complemented by scanning electron microscopy-energy dispersive spectroscopy （SEM-EDS）, X-ray diffraction（XRD）, and particle size analysis to characterize the soils thoroughly. The results indicated that the adsorption processes of P and As in the three soil types（paddy soil, cinnamon soil, and red soil）followed the quasi-second-order kinetic model and the Freundlich model, suggesting that multi-layer chemical adsorption took place on the heterogeneous surfaces of the soils. The adsorption capacity of soil for P and As（Ⅴ）is influenced by pH value, ionic strength, and ion type. As the initial pH value increases and ionic strength decreases, the adsorption capacity of the soil diminishes. Based on SEM-EDS and XRD analysis, the differences in surface morphology and element composition of the three soils were revealed. The surface of cinnamon soil is rough and rich in iron and aluminum oxides. These minerals significantly enhance their adsorption capacity for P and As（ Ⅴ ） through ligand exchange and surface complexation. The surface of red soil is smooth and has a high quartz content, resulting in its weaker adsorption capacity. Through transport experiment, it was found that the migration behavior of P and As（Ⅴ）in the three soil types increased with rising pH value. Among them, P and As（Ⅴ）have the strongest migration ability in red soil. This is because the coarse particles and high pore connectivity of red soil promote the migration of P and As（Ⅴ）, while the fine particles and high adsorption capacity of cinnamon soil inhibit the migration of pollutants. Additionally, the migration ability of As（Ⅴ）was significantly greater than that of P under varying pH conditions. Moreover, increased ionic strength exhibited an inhibitory effect on the migration capacities of both P and As（Ⅴ）across different soil types. This study reveals the differences in the adsorption and migration behavior of P and As（Ⅴ）in different soils, provides important scientific basis for a deeper understanding of the environmental behavior of phosphorus and arsenic in soils. |
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