Investigation of Mechanisms of Surfactant-Induced Hydraulic Conductivity Changes in Soil Flushing Operations

这项研究的目的是了解表面活性剂处理土壤时引起土壤导水率变化的基本机理，并开发一个数学模型，供科学家和工程师用特定的表面活性剂和剂量处理特定土壤时预测土壤导水率变化的幅度和方向。将研究粘土含量和类型、表面活性剂类型和浓度以及土壤结构的作用，以促进对适用于任何土壤-表面活性剂体系的基本理解和预测能力。两种非离子表面活性剂和一种阴离子表面活性剂将分别在三个相中进行考察。前两个阶段将侧重于了解已确定的改变水力传导性的四种机制。第一阶段将调查对流体或土壤介质的直接物理效应和诱导的次生化学反应；第二阶段将调查土壤团聚体的破坏和细粉的产生，以及表面活性剂与粘土的相互作用。第三阶段的目的是检查人工土壤中的变量组合，以了解各个机制之间的相互关系，并评估在前两个阶段发展的预测能力。此外，第三阶段的主要目标将是开发一种能够描述实验工作观察结果的数学工具，以此为基础开发预测能力。拟议的项目有可能对基础科学和对土壤-表面活性剂相互作用的理解以及将这些知识应用于现实世界的补救项目作出重大贡献。

The objective of this research is to learn the fundamental mechanisms that produce a change of hydraulic conductivity in soil when treated with surfactants and to develop a mathematical model that can be used by scientists and engineers to predict the magnitude and direction of hydraulic conductivity change upon treatment of a particular soil with a specific surfactant and dose. The roles of clay content and type, of surfactant type and concentration and of soil structure will be investigated in order to advance fundamental understanding and predictive capabilities applicable for any soil-surfactant system. Two nonionic and one anionic surfactants will be examined in each of three phases. The first two phases will focus on understanding the four identified mechanisms by which hydraulic conductivity is altered. The first phase will investigate direct physical effects on fluid or soil media and induced secondary chemical reactions; the second phase will investigate the destruction of soil aggregate and production of fines, and surfactant-clay interactions. The third phase is designed to examine combinations of variables in artificial soils to understand the interrelationships among the individual mechanisms and to assess the predictive abilities developed in the first two phases. In addition, a primary goal of the third phase will be the development of a mathematical tool capable of describing the observations of the experimental work, from which predictive capabilities will be developed. The proposed project has the potential of making significant contributions to the basic science and understanding of soil-surfactant interaction and to the application of that knowledge to real-world remediation projects.