Presidential Young Investigators Award: Effects of Inter- facial Properties on Contaminant Transport and Transforma- tions in Aquatic Systems

PYI：界面性质对污染物在水生系统中传输和转化过程的影响这是一个奖项，旨在支持关于微量污染物的吸附程度和速率如何受界面性质影响的研究吸附颗粒的表面化学和物理特性。虽然松弛动力学研究表明，吸附/脱附反应的速度相当快，但在间歇或塔式反应器中观察到的接近平衡的速度要慢得多。这表明，由粒子缔合引起的物理传输过程控制着吸附速度。这个项目涉及通过改变颗粒-流体流体动力学，颗粒大小和孔隙率，以及矿物学，使用包括间歇式，柱式，以及差动柱式反应器和测定表面和界面性质的变化如何影响多孔介质中的两相流动。影响单独有机液体在地下传输的一个关键因素是系统的三个界面的性质：有机液体-水、水-固体和有机液体-固体。这些性质决定了润湿性，而润湿性反过来又影响着两个液体流经的孔隙网络。关于无机和有机溶质如何通过改变界面性质来改变润湿性，人们知之甚少。对这位总统青年调查员的初步支持是为了确定矿物表面和界面性质对地下水中环境污染物的迁移和转化过程的影响。地质地下地层的表面和界面性质控制着国家关注的各种问题。从再悬浮的湖泊或海洋沉积物中释放出疏浚作业产生的多卤化联苯和重金属、地下地质储存库中的放射性核素泄漏到地下水中、或危险有机液体在泄漏和废物处置场的迁移都是这项研究涉及的问题的例子。

PYI: Effects of Interfacial Properties on Contaminant Transport and Transformation Processes in Aquatic Systems This is an award to support research on how the extent and rates of sorption of trace contaminants are effected by the surface chemical and physical characteristics of the sorbent particles. While relaxation kinetic studies have shown that rates of adsorption/desorption reactions are quite rapid, the observed rates of approach to equilibrium in batch or column reactors are much slower. This suggests that physical transport processes caused by particle association control the rates of sorption. This project involves an investigation of the relative importance of surface chemical and physical processes on the extent and rate of sorption, by varying the particle-fluid hydrodynamics, particle size and porosity, and mineralogy of sorbent, using various reactor types including batch, column, and differential column reactors and determination of how changes in surface and interfacial properties affect two-phase flow in porous media. One key factor affecting the transport of a separate organic liquid in the subsurface is the properties of the three interfaces of the systems: organic liquid-water, water-solid, and organic liquid-solid. These properties determine wettability which, in turn, influence the pore networks through which the two liquid phases flow. Very little is known about how inorganic and organic solutes change wettability by changing the interfacial properties. This initial increment of support for this Presidential Young Investigator is aimed at identifying the effects that mineral surfaces and interfacial properties have on transport and transformation processes of environmental contaminants in groundwater aquifers. A variety of problems of national concern are controlled by surface and interfacial properties of geologic subsurface formations. The release of polyehlarinated biphenyls and heavy metals from resuspended lake or ocean sediments from dredging operations, the leakage of radionuclides into the groundwater from subsurface geologic repositories, or the migration of hazardous organic liquid at spill and waste disposal sites are examples of the issues toward which this research is addressed.