Collaborative Research: The Effect of Dynamic Surface-Associated Phase Change on Environmental Mobility in Unsaturated Environments

合作研究：动态表面相关相变对不饱和环境中环境迁移性的影响

• 批准号: 1336083
• 负责人: Tohren Kibbey
• 金额: $ 18.47万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1336083&HistoricalAwards=false
• 关键词: Collaborative; Research; Effect; Dynamic; Surface

CBET-1336083/1336579Tohren C. Kibbey/Charalambos PapelisThe University of Oklahoma/New Mexico State UniversityNatural and engineered processes can cause the water content of soils in the unsaturated zone to vary significantly over time. Dynamic decreases in water content caused by evaporation can cause local increases in the concentrations of contaminants and other porewater constituents, which can drive enhanced contaminant sorption and the formation of contaminant precipitates. Because sorption/desorption and precipitation/dissolution processes tend to be strongly rate-limited, dynamic water content changes can have a strong influence on the long-term mobility of inorganic and organic contaminants, with these processes either increasing or decreasing long-term mobility. To date, little quantitative information is available that would allow realistic modeling of dynamic sorption or phase change processes in unsaturated media, or prediction of their impact on contaminant mobility. The objective of this work is to quantify the link between dynamic changes in water content and composition and the corresponding phase changes of contaminants that take place, with emphasis on quantifying the ultimate connection between phase changes and subsurface mobility. This project will initially focus on six separate chemical contaminants of environmental concern, four organic compounds and two inorganic compounds, all selected to exhibit a wide range of chemical behaviors (adsorption, speciation, complexation, solid formation) likely to influence behavior under dynamic unsaturated conditions. Work will be focused around three tightly-coupled tasks and will include 1) dynamic unsaturated experiments; 2) batch analyses and spectroscopic-microscopic measurements; and 3) coupled dynamic geochemical/unsaturated transport modeling to interpret the results of the first two tasks and to synthesize and expand the results of experimental work to better understand and predict environmental implications of phase change on long term contaminant mobility. The results of the proposed work will provide the tools needed to enhance our understanding of contaminant phase changes during natural and engineered changes in water content, and will provide quantitative information needed for enhanced decision making processes for managing and remediating contamination in the unsaturated zone.The water content of soils can vary substantially over time either because of natural processes, such as precipitation and evaporation, or because of human activities. This water content variability can have a dramatic effect on the mobility of hazardous inorganic substances, such as metals and radioactive compounds, as well as organic substances, such as pharmaceuticals, pesticides, and hydrocarbons. This project will enhance our ability to predict the movement of organic and inorganic contaminants in the soil environment as a function of soil water content. Our improved understanding of the link between soil water content and contaminant mobility in the soil will enable the development of improved soil remediation techniques.

CBET-1336083/1336579 Tohren C.Kibbey/Charalumbers Papelis俄克拉荷马大学/新墨西哥州州立大学自然和工程过程会导致非饱和带土壤的水分随着时间的推移发生显著变化。蒸发引起的水分含量的动态下降可能会导致污染物和其他孔隙水成分的局部浓度增加，这可能会导致污染物的吸附增强和污染物沉淀的形成。由于吸附/解吸和沉淀/溶解过程往往受到强烈的速率限制，动态的水分含量变化可能会对无机和有机污染物的长期移动性产生强烈的影响，这些过程会增加或减少长期的移动性。到目前为止，几乎没有定量的信息可以用来对非饱和介质中的动态吸附或相变过程进行真实的建模，或者预测它们对污染物迁移的影响。这项工作的目的是量化水含量和成分的动态变化与污染物发生的相应相变之间的联系，重点是量化相变与地下流动性之间的最终联系。该项目最初将重点关注六种独立的环境化学污染物，四种有机化合物和两种无机化合物，所有这些污染物都表现出广泛的化学行为(吸附、形态形成、络合、固体形成)，可能会影响动态不饱和条件下的行为。工作将集中于三项紧密耦合的任务，包括1)动态非饱和实验；2)批量分析和光谱-显微测量；以及3)耦合的动态地球化学/非饱和运移模拟，以解释前两项任务的结果，并综合和扩展实验工作的结果，以更好地理解和预测相变对污染物长期迁移的环境影响。拟议工作的结果将为我们提供所需的工具，以加强我们对自然和工程改变水分期间污染物相变化的了解，并将为加强管理和修复非饱和地带污染的决策过程提供所需的定量信息。土壤的水分含量可能会随着时间的推移而发生很大变化，无论是由于自然过程，如降水和蒸发，还是由于人类活动。这种水分含量的变化可能会对有害无机物质(如金属和放射性化合物)以及有机物质(如药品、杀虫剂和碳氢化合物)的流动性产生巨大影响。该项目将提高我们预测土壤环境中有机和无机污染物随土壤水分变化的能力。我们对土壤水分含量和污染物在土壤中移动性之间的联系的更好的理解将使改进的土壤修复技术的发展成为可能。