Interdisciplinary Study of Chemical and Transport Processes at a Plasma-Liquid Interface

Clarkson University, Potsdam NY

Investigators

Abstract

This project focuses on improving the understanding of the fundamental processes that occur at or near interfaces of a plasma, a cloud of ionized gas composed of electrons, ions and neutral particles, and a liquid. A plasma that is created above or within a liquid can have a number of uses. For example, plasma discharges have been used to sterilize water, fruit juices, and milk, to remove harmful chemicals from water, to create new materials, and for medical applications. Some cancer-causing pollutants found in the environment can only be treated using plasmas. In material processing technologies plasmas formed directly in liquids that do not contain water, such as alcohols, can transform these liquids into different useful products including carbon nanotubes, a material with unique properties that is currently used in a wide variety of electronics. A better understanding of the physical and chemical processes near the plasma-liquid interface will not only help to improve the existing plasma-based processes, but will also open new applications in biomedicine, agriculture, energy, green chemistry and pollutant mitigation. The region near the plasma-liquid interface exhibits complex dynamics that depend on the formation of reactive radicals, ions and high energy electrons, their transport across the interface, and the physics of the bulk fluid motion for mixing and transport. These processes are interrelated and incorporate both physical and chemical dynamics. The overall goal of this research project is to determine relationships between the physical and chemical processes occurring at the plasma-liquid interface in a system where the plasma discharge contacts the liquid surface. Two specific goals of this study are to: (1) Correlate the bulk liquid transport processes with the plasma-liquid interface dynamics and (2) Determine the significance of the plasma excited species transport in the kinetics of interfacial processes. The approach for achieving the goals of this multidisciplinary study is to identify degradation mechanisms of several compounds of interest and apply quantitative optical diagnostic tools (i.e. Particle Image Velocimetry and Laser-Induced Fluorescence) to understand the physics at the interface as well as the role bulk liquid transport plays in the dynamics of the degradation process. Further, molecular dynamics simulations will be performed to develop a quantitative understanding of the microstructure of the studied compounds at the gas-liquid interface.