Characterization of structure and properties of bioorganoclays - perspective hybrid materials

从微生物物质和粘土矿物中控制制备生物有机粘土复合材料具有很大的环境、地质和技术意义，因为可以获得具有特定性质的材料。此外，微生物物质和粘土之间的相互作用是生物地球化学环境中常见的界面现象，例如在土壤和沉积物中。然而，这些材料的形成和相互作用的基本机制仍然知之甚少。拟议项目的目标是制备，表征和模拟基于微生物来源的有机物和选定的粘土矿物的新生物有机粘土。预期的是具有新的具体特性的材料，例如增强的吸附能力。该提议基于以下假设：根据生物有机分子或微生物材料的来源、类型和大小以及粘土的类型，可以制备具有不同结构和性质的生物有机粘土。预期有两种基本类型，i）生物有机粘土，其具有被生物有机物质涂覆的粘土颗粒，仅有限地渗透或不渗透到层间廊道中（高岭石基），和ii）生物有机粘土，其具有分布在层间廊道中和/或粘土颗粒的外表面上的生物有机物质（蒙脱石基）。关于这一点，还预期生物有机粘土颗粒的形状和尺寸、孔体积结构、生物有机涂层与粘土基质的稳定性和结合以及表面上活性位点的量和类型的差异。生物有机材料和粘土之间的相互作用机制，以及由此产生的结构和物理化学性质将通过多种实验方法（例如XPS，NMR，TEM，NanoSIMS）结合分子建模进行探索。我们计划使用纯生物有机分子（例如磷脂）以及更复杂的微生物生物量。由纯生物分子制备的生物有机粘土的表征将有助于理解更复杂的生物质与粘土的相互作用。这种方法将导致生物有机粘土材料的复杂和详细的（分子尺度）表征，例如，粘土的夹层和外表面上的生物有机物质的排列。在物理化学性质方面，生物有机粘土的吸附能力随生物有机物质和粘土矿物的种类和数量的变化将是重点。为了验证这一点，实验和计算机模拟将集中在确定所制备的生物有机粘土的结构，组成和性能。拟议的双边项目将受益于德国（实验）和奥地利（建模）小组之间的有效合作。

Controlled preparation of bioorganoclay composites from microbial matter and clay minerals is of great environmental, geological, and technological interest because materials with specific properties can be obtained. Further, interactions between microbial matter and clays are a common interfacial phenomenon in the biogeochemical environment, such as in soils and sediments. However, fundamental mechanisms governing formation and interactions of these materials are still poorly understood. The objective of the proposed project is to prepare, characterize, and model new bioorganoclays based on organic matter of microbial origin and selected clay minerals. Expected are materials with new specific properties, for example enhanced sorption capacity. The proposal is based on the hypothesis that depending on origin, type, and size of bioorganic molecules or microbial material and on the type of the clay, bioorganoclays with different structure and properties can be prepared. Two basic types are expected, i) bioorganoclays having clay particles coated by bioorganic matter with only limited or no penetration into interlayer galleries (kaolinite-based), and ii) bioorganoclays having distributed bioorganic matter in the interlayer galleries and/or on the external surfaces of clay particles (montmorillonite-based). With respect to this also differences in shape and size of biorganoclay particles, pore volume structure, stability and binding of the bioorganic coating to clay matrices, and the amount and type of active sites on surfaces are expected. Interaction mechanisms between bioorganic material and clays, and the resulting structure and physicochemical properties will be explored by multiple experimental methods (e.g. XPS, NMR, TEM, NanoSIMS) in combination with molecular modeling. We plan to use pure bioorganic molecules (e.g. phospholipids) and also more complex microbial biomass. Characterization of the bioorganoclays prepared from pure biomolecules will help in the understanding of interactions of more complex biomass with clays. This approach will lead to complex and detailed (molecular-scale) characterization of the bioorganoclay materials, e.g. arrangement of the bioorganic species in interlayer and on external surfaces of clays. Referring to the physicochemical properties, changes of the adsorption capacity of the bioorganoclays with respect to type and amount of the bioorganic materials and clay minerals will be in focus. To verify this, experiments and computer simulations will be focused to determine the structure, composition, and properties of the prepared bioorganoclays. The proposed bilateral project will profit from effective collaboration between the German (experiments) and Austrian (modeling) group.