Relative Potential of Different Plasma Forming Gases in Degradation of Rhodamine B Dye by Microplasma Treatment and Evaluation of Reuse Prospectus for Treated Water as Liquid Fertilizer

Abstract

Degradation of Rhodamine B in aqueous solution was carried out with different microplasma medium generated from air, oxygen, nitrogen and argon gases at atmospheric pressure. Rhodamine B (RhB) aqueous solution was prepared (10 ppm) and treated in microplasma reactor at different treatment time and applied potential. The RhB degradation was mainly due to the hydroxyl radical formation, during the plasma treatment, which was identified by terephthalic acid probe method. The result shows that the oxygen microplasma produced more hydroxyl radicals than air, nitrogen and argon. The degradation percentage of RhB solution with respect to different plasma gases were estimated by using UV–Vis absorption spectra which reveals that the oxygen microplasma is most competent for complete degradation within petite time followed by air, nitrogen and argon. Post discharge phenomenon was observed in air and nitrogen microplasma treated solution, which could reduce the treatment time to accomplish complete dye degradation. The sample treated with air and nitrogen microplasma for 3 min resulted in the degradation percentage of 62.3% and 60.4%, respectively, and the complete degradation was obtained after 7 and 10 h of post discharge, respectively. Further an attempt was made to verify the reusability of air microplasma treated solution as a liquid fertilizer in cultivation purpose using Mung bean (Vignaradiata). The obtained results were encouraging as the treated water enhanced the seed germination and plant growth notably.