Effects of Carbon Particles on Aqueous Phase Pulsed Streamer Corona

摘要

Pulsed streamer corona technology utilizes a non-thermal plasma high voltage discharge to break down various airborne and aqueous phase organic pollutants. Pulsed streamer corona discharge in a reactor using a point-to-plane electrode geometry has been studied with well-mixed aqueous solutions containing various salts (sodium chloride, potassium chloride, and calcium chloride) and particles in suspension (powdered activated carbon, porous silica gel, non- porous glass spheres, and elemental copper). The result that solution conductivity governs the electrode breakdown voltage is independent of both the salt composition and the particle properties (i.e., total surface area, particle size, conductivity, and dielectric constant). Powdered activated carbon in aqueous suspension also dramatically reduces the reactor electric power as a function of applied voltage. Elemental analysis using PIXE (proton-induced x-ray emission) of the activated carbon and the water leachate from washed activated carbon, coupled with pulsed corona treatment experiments using washed activated carbon, show that interactions of activated carbon with potassium salts are responsible for the lower reactor power. With the lower power consumption, greater amounts of contaminants can be removed at a lower power usage. The combination of pulsed corona and activated carbon enhances phenol removal through bulk reactions, adsorption, and corona-induced surface reactions. Primary oxidation products of phenol were also measured. A reaction and diffusion model was derived to analyze the phenol decomposition with combined bulk liquid and particle surface reactions.