Aqueous chemistry and biochemistry of silicon

硅酸盐--硅(Si)和氧的化合物--在自然界和工业中都非常重要。仅这两种元素就占地壳重量的75%，而硅酸盐骨架中的元素占另外22.5%。硅酸盐的侵蚀、迁移和沉积均受水化学控制。然而，是生物学控制了整个全球硅循环。硅藻和海绵等原始生物占据了最大份额，它们利用硅化细胞壁和骨架结构，在这样做的过程中，封存了全球二氧化碳排放量的主要百分比。植物，包括所有的粮食作物，需要持续的硅供应来抵御无数的生物和非生物胁迫。在哺乳动物中，饮食中硅的摄入量与结缔组织的健康生长相关。然而，尽管硅具有显著的生物学重要性，但人们对硅与生物在分子水平上的相互作用知之甚少。材料科学还需要更多的硅酸盐水化学知识，以实现混凝土、沸石催化剂、陶瓷、半导体、涂料和纸张等关键工业商品的可持续生产和改善性能。例如，混凝土是一种低成本、低能源的硅酸盐集合体，是地球上使用最广泛的人造物质，年产量近400亿吨(约20千米)，而且还在迅速上升。由于每生产一吨水泥会排放近一吨二氧化碳，混凝土排放的温室气体约占人为温室气体排放量的7%-10%。在不牺牲性能的情况下减少对环境的影响将需要对水泥的化学成分进行改变。我的研究计划的长期目标是解开水硅的基本化学，并将这些知识转化为农业、人类营养学、医学和材料科学的利益。

Silicates – compounds of silicon (Si) and oxygen – are fundamentally important in both nature and industry. These two elements alone constitute 75 wt% of the Earth’s crust, while elements which fit into silicate frameworks represent another 22.5%. Erosion, migration and deposition of silicates are all controlled by aqueous chemistry. Yet it is biology that controls the overall global Si cycle. Primitive organisms such as diatoms and sponges take up the greatest share, using it to construct silicified cell walls and skeletal structures and, in so doing, sequester a major percentage of global CO2 production. Plants, including all grain crops, require a constant Si supply to defend against myriad biological and non-biological stresses. In mammals, dietary Si intake correlates with healthy connective tissue growth. Despite its appreciable biological importance, however, remarkably little is known about silicon’s interaction with organisms at the molecular level. Better knowledge of aqueous silicate chemistry is also needed in materials science to achieve sustainable production and improved properties of key industrial commodities such as concrete, zeolite catalysts, ceramics, semiconductors, coatings and paper. For example, concrete, a low-cost low-energy aggregate of silicates, is the most widely used man-made substance on Earth, with an annual production of nearly 40 billion tons (ca. 20 km3) and quickly rising. Because nearly a ton of CO2 is released during the manufacture of every ton of cement, concrete accounts for some 7-10% of man-made greenhouse gas emissions. Decreasing its environmental impact without sacrificing performance will necessitate changes being made to the chemistry of cement. The long-term goals of my research program are to unravel the fundamental chemistry of aqueous silicon and to translate that knowledge for the benefit of agriculture, human nutrition, medicine and materials science.