Removal of Rhodamine B Dye by Plasma Jet Oxidation Process

Abstract

Recently, nonthermal atmospheric pressure plasma has been developed as a novel tool in removal of water pollutants. Rhodamine B dye, widely used in textiles and biology, is toxic to both humans and animals, hence removing residual Rhodamine B in solution is necessary. In this work, we have setup a cold plasma jet system and used it to effectively remove Rhodamine B in the solution. We have shown that the main oxidation substance responsible to remove Rhodamine B is the hydroxyl radical (•OH). By studying the effect of the hydrogen peroxide (H₂O₂) concentration in the initial and later was produced in the solution, the plasma power, and the Ar gas flow speed on the dye remove rate, we have identified 2 main reaction pathways to generate hydroxyl radical (•OH). Both of these reaction pathways involve high-energy electrons interacting with water and O₂ in the solution and in the ambient air. Our work provides important information to understand the mechanism of dye removal by cold plasma treatment.