A Combined Computational and Benchtop Chemistry Approach to a Model of the Formation, Growth and Precipitation of Hydroxyaluminosilicates.

在湖泊、河流和海洋等自然水域中发现的溶解硅的形式被称为硅酸。硅酸分子由一个硅原子组成，周围有四个羟基(OH)，呈四面体排列。这种分子几乎可以被描述为化学惰性，因为它没有已知的有机化学，也几乎没有已知的无机化学。后者是这项提议的主题，因为我们已经确定了硅酸与铝在形成我们所称的羟基铝硅酸盐(HAS)时所具有的独特的无机化学。我们已经能够确定中性硅酸分子如何与由氢氧化铝组成的‘表面’反应，形成两个离散的HAS，我们称之为HAS‘A’和HAS‘B’。我们已经能够确认这些固相的结构，并给出它们的组成和溶解性的定量数据。我们已经展示了它们如何在其结构中同时结合氟和磷。我们在这一领域的所有成就都使这一化学被纳入了权威的无机化学教科书中。然而，仍然有大量的知识需要了解，特别是它们的形成速度将如何对它们在特定环境中的化学和生物作用产生深远的影响。我们已经确定，在铝和硅的生物地球化学循环中，HAS都是关键的次生矿物。因此，我们知道这种化学在硅的生物可利用性方面发挥着重要作用，例如，对于生物硅化(为结构作用建立二氧化硅框架的生物体)和铝，它将铝排除在生物群之外。硅酸作为铝潜在毒性的天然拮抗剂的后一种作用已经被我们自己以及随后的许多其他基团广泛地证明，这可能是硅在生物体中的主要作用。因此，尽可能多地了解HAS的形成不仅将使一些新的和令人兴奋的无机化学成为可能，还将使我们了解这种化学在生化进化中所起的作用。特别是，在这个项目中，我们希望建立一个碳氢化合物形成动力学的计算模型，因为这种模型对于预测铝的生物可利用性非常重要的任何应用都应该是非常有价值的。我们将使用最先进的台式化学，包括颗粒大小测定和质谱分析，来建立关于如何形成、聚集并最终以运动惰性次生矿物状固体相的形式沉淀的新的创新数据。这些数据将用于我们新的HAS形成动力学模型，以产生一个有效和可预测的计算模型，该模型将容易被许多不同的感兴趣的各方访问，包括在基础化学中的应用，以及在应用化学和毒理学中的应用。

The form of dissolved silicon which is found in natural waters such as lakes, rivers and the sea is called silicic acid. A molecule of silicic acid is composed of an atom of silicon surrounded by 4 hydroxyl (OH) groups in a tetrahedral arrangement. This molecule can almost be described as chemically inert as it has no known organic chemistry and almost no known inorganic chemistry. The latter is the subject of this proposal as we have identified the unique inorganic chemistry of silicic acid with aluminium in forming what we have called hydroxyaluminosilicates (HAS). We have been able to identify how the neutral silicic acid molecule reacts with a 'surface' composed of aluminium hydroxide to form two discrete HAS which we have called HAS'A' and HAS'B'. We have been able to confirm the structures of these solid phases and assign quantitative data to their composition and solubiblity. We have shown how they may also incorporate both fluoride and phosphate in their structures. All of our achievements in this field have now resulted in this chemistry being included in authoratative text books on inorganic chemistry. However, there is a great deal still to learn about HAS and in particular how their rate of formation will have profound influences upon their chemical and biological roles in specific environments. We have identified HAS as critical secondary minerals in the biogeochemical cycles of both aluminium and silicon. Thus we know that this chemistry plays an important role in the biological availability of silicon, for example, for biosilicification (organisms which build silica frameworks for structural roles) and aluminium, it keeps aluminium out of biota. The latter role of silicic acid as the natural antagonist to the potential toxicity of aluminium has been widely demonstrated by ourselves and, following us, many other groups and is probably the major role of silicon in living organisms. Thus gaining as much understanding as is possible about the formation of HAS will not only enable some new and exciting inorganic chemistry it will also inform us as to the role this chemistry plays and has played in biochemical evolution. In particular, in this project we wish to build a computational model of the kinetics of HAS formation as such a model should be invaluable to any application where it is important to be abe to predict the biological availability of aluminium. We will use state-of-the-art benchtop chemistry including particle-sizing and mass spectrometry to establish new and innovative data concerning how HAS form, aggregate and eventually precipitate as kinetcially inert secondary mineral-like solid phases. These data will be used in our new kinetic model of HAS formation to produce an effective and predictive computational model which will be readily accessible by many different interested parties including applications in fundamental chemistry but also in applied chemistry and in toxicology.