Collaborative Research: NIRT: Surface Reactivity of Nanocrystalline Oxides and Oxyhydroxides: Implications for Processes in the Environment

合作研究：NIRT：纳米晶体氧化物和羟基氧化物的表面反应性：对环境过程的影响

• 批准号: 0124036
• 负责人: Peter Cummings
• 金额: $ 17.01万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-15 至 2003-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0124036&HistoricalAwards=false
• 关键词: Collaborative; Research; NIRT; Surface; Reactivity

EAR-0123967EAR-123998EAR-0124036EAR-0124001Crystals with nanometer-scale dimensions formed by chemical weathering and biomineralization reactions are found in rivers, lakes, oceans, soils, sediments, and atmospheric dust. Because of their novel size-dependent properties, nanoparticles may play disprotionately large roles in environmental processes. However, the variation of reactivity of geologically important nanomaterials with particle size has received little attention. The tendency of ions to adsorb onto nanocrystalline metal oxide surfaces is predicted to be size-dependent. Adsorption will be studied experimentally over the temperature range of 0 - 150 degrees C in gases and environmentally-relevant aqueous solutions. Models will be developed to quantitatively explain differences between results for nanoparticles and those obtained on macroscopic equivalents. If nanocrystals grow via oriented aggregations, as has been shown previously, adsorbed ions (e.g. phosphate, arsenate, and zinc adsorbed from solution onto iron oxyhydroxide surfaces), may be incorporated into point defects. This may represent an important environmental ion sequestration pathway, with direct relevance to the long-term fate of nutrients and contaminants. Coupling of aggregation and adsorption under controlled conditions may also provide a new approach for creation of synthetic materials with technologically interesting properties. Ion sequestration during nanocystal growth will be tested experimentally and explored via molecular modeling and simulation. Calorimetric studies designed to measure surface and adsorption energies will provide date to be used in models that will explore size-dependent reactivity. This proposal was submitted in response to the solicitation "Nanoscale Science and Engineering" (NSF 00-119).

EAR-0123967EAR-123998EAR-0124036EAR-0124001在河流、湖泊、海洋、土壤、沉积物和大气灰尘中发现了由化学风化和生物矿化反应形成的纳米级晶体。 由于其新颖的尺寸依赖性特性，纳米粒子可能在环境过程中发挥不成比例的重要作用。 然而，具有地质意义的纳米材料的反应性随粒径的变化却很少受到关注。 离子吸附到纳米晶金属氧化物表面的趋势预计与尺寸相关。 将在 0 - 150 摄氏度的温度范围内对气体和与环境相关的水溶液中的吸附进行实验研究。 将开发模型来定量解释纳米颗粒结果与宏观等效物获得的结果之间的差异。 如果纳米晶体通过定向聚集生长，如前所述，吸附的离子（例如从溶液中吸附到羟基氧化铁表面上的磷酸盐、砷酸盐和锌）可能会并入点缺陷中。 这可能代表了一种重要的环境离子封存途径，与营养物和污染物的长期命运直接相关。 在受控条件下聚集和吸附的耦合也可能为创建具有技术上有趣的特性的合成材料提供新的方法。 纳米晶体生长过程中的离子封存将通过分子建模和模拟进行实验测试和探索。 旨在测量表面和吸附能的量热研究将为探索尺寸依赖性反应性的模型提供数据。 该提案是为了响应“纳米科学与工程”（NSF 00-119）征集而提交的。