Abstract：
Biochars and organoclays have been proposed as efficient adsorbents to reduce the mobility of agrochemicals in soils. However, following their application to soils, these adsorbents undergo changes in their physicochemical properties over time due to their interaction with soil components. In this study, the adsorption capacity of a commercial biochar and a commercial organoclay for the antibiotic sulfamethoxazole (SFMX) and the pesticide ethofumesate (ETFM) was evaluated over aging periods of 3 months in the laboratory and 1 year in the field, subsequent to their application to a Mediterranean soil. The results showed that the adsorption of SFMX and ETFM in the soil amended with the adsorbents was greater than in the unamended soil, but for both chemicals, adsorption decreased with aging of the adsorbents in the soil. Characterization of the adsorbents before and after aging revealed physical blocking of adsorption sites by soil components. The loss of adsorption capacity of the adsorbents upon aging led to higher leaching of SFMX and ETFM in the soil containing field-aged adsorbents, although leaching remained lower than in unamended soil. Our findings reveal that, under the Mediterranean environment studied, the efficacy of the studied materials as adsorbents is maintained to a considerable extent for at least one year after their field application, which would have positive implications in their use for attenuating the dispersion of agricultural contaminants in the environment.
摘要：
生物炭和有机粘土已被提出作为有效的吸附剂，以降低农业化学品在土壤中的流动性。然而,在它们应用于土壤后，由于这些吸附剂与土壤成分的相互作用，它们的物理化学性质会随着时间的推移而发生变化。在这项研究中,在实验室和现场1年的老化期间，评估了商业生物炭和商业有机粘土对抗生素磺胺甲恶唑（SFMX）和农药乙醇酸酯（ETFM）的吸附能力，随后将其应用于地中海土壤。结果表明，SFMX和ETFM在吸附剂改良土壤中的吸附量大于未改良土壤中的吸附量。但是对于这两种化学物质，吸附量随吸附剂在土壤中的老化而降低。老化前后吸附剂的表征表明，土壤成分对吸附位点的物理阻断。吸附剂老化后吸附能力的损失导致SFMX和ETFM在含有田间老化吸附剂的土壤中的浸出率较高，尽管淋溶仍低于未改良的土壤。我们的发现表明,在研究的地中海环境下，所研究的材料作为吸附剂的功效在其现场应用后至少一年内保持相当大的程度，这将对它们用于减少农业污染物在环境中的扩散具有积极意义。
