Hydration affected soil:water sorption processes of xenobiotics - experiments and modeling approaches

SOM不是一种被动的吸着剂，但可以被吸着剂物理改变。水分子和阳离子已经证明了这一点。这里假设有机异物的吸附参与了SOM的形成，并导致了SOM物理结构和物理化学性质的变化。这些变化通过吸附过程反馈。二次吸附物的吸附和(竞争)吸附已被证明是能够对过程进行机械(热力学)模拟的敏感措施。为此，选择了10种具有不同物理化学性质和对土壤有机质的预期影响的溶质，并将其与3个不同有机质含量和组成的土壤样品和一个多聚半乳糖醛酸钙网络(Ca-PGA)组合作为SOM模型。在批量试验和不同条件(阳离子交联度、温度、溶剂性质、有机矿物结合、陈化时间)下进行测试，将获得关于吸附程度、非线性、滞后、动力学和竞争力的数据。相应地，利用漂移、DSC、1H-核磁共振和表面表征方法，对吸附诱导变化前后的SOM进行了彻底的表征，并确定了SOM-山梨酸盐的结合机理。数据将使用机械论、多点和多相模型以及分子力学计算模型进行组合和建模。

SOM is not a passive sorbent but may be physically altered by the sorbate. This was already shown for water molecules and cations. Here it is hypothesized that sorption of organic xenobiotics takes part in the formation of SOM and induces changes in SOM physical structure and physicochemical properties. These changes feed back on sorption processes. Sorption and the (competitive) sorption of secondary sorbates have been shown to be sensitive measures enabling mechanistic (thermodynamic) modeling of processes. For that purpose, ten solutes offering a range of physicochemical properties and expected effects on SOM were selected and will be combined with three soil samples with different SOM quantity and composition and a polygalacturonic calcium network (Ca-PGA) as model SOM. Tested in batch trials and under varied conditions (cation crosslinking, temperature, solvent properties, organo-mineral association, aging time) data on sorption extent, nonlinearity, hysteresis, kinetics and competitiveness will be obtained. Correspondingly, SOM are thoroughly characterized before and after sorption induced changes and SOM-sorbate binding mechanisms are identified, using DRIFT, DSC, 1H-NMR, and methods for surface characterization. Data will be combined and modeled using mechanistic multisite and multiphase models and molecular mechanics computational modeling.