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重要的环境、地质和技术意义，因为可以获得具有特定性质的材料。此外，微生物物质与粘土之间的相互作用是生物地球化学环境（如土壤和沉积物）中常见的界面现象。然而，控制这些材料形成和相互作用的基本机制仍然知之甚少。该项目的目标是基于微生物来源的有机物和选定的粘土矿物制备、表征和模拟新的生物有机粘土。期望的是具有新的特定性能的材料，例如增强的吸附能力。该提案基于这样一个假设：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，可以制备出具有不同结构和性质的生物有机粘土。预计有两种基本类型，i)生物有机粘土的粘土颗粒被生物有机质包裹，只有有限或没有渗透到层间通道（高岭石基），ii)生物有机粘土的生物有机质分布在层间通道和/或粘土颗粒的外表面（蒙脱石基）。在这方面，生物有机粘土颗粒的形状和大小、孔隙体积结构、生物有机涂层与粘土基质的稳定性和结合，以及表面活性位点的数量和类型也存在差异。通过多种实验方法（如XPS， NMR， TEM, NanoSIMS）结合分子建模，探索生物有机材料与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。我们计划使用纯生物有机分子（如磷脂）和更复杂的微生物生物量。表征由纯生物分子制备的生物有机粘土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复杂而详细的（分子尺度）表征，例如，生物有机物种在粘土层间和外表面的排列。结合生物有机粘土的物理化学性质，重点研究了其吸附能力随生物有机物和粘土矿物种类和数量的变化。为了验证这一点，实验和计算机模拟将集中于确定所制备的生物有机粘土的结构、组成和性质。拟议中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.