Enhanced Degradation of Organic Pollutants with Microwave-induced Plasma-in-liquid (MPL): Case of Flame Retardant Tetrabromobisphenol-A in Alkaline Aqueous Media

Abstract

Introduction One of the first applications of advanced oxidation processes AOPs was reported in 1987 by Glaze 1 , who proposed that such processes involve the generation of OH in sufficient quantity to affect water purification. Several AOPs have been described since, many of which involve use of the powerful oxidizing hydroxyl radical OH that can oxidize and degrade organic pollutants from contaminated air and polluted aqueous ecosystems. These AOPs are termed advanced, because the chemical reactions are essentially the same except that they occur considerably faster billions of times vis-à-vis reactions that occur if the pollutants were exposed solely to a natural environment 2. Other AOPs include UV/O 3 , UV/H 2 O 2 , Fenton, photo-Fenton, non-thermal plasmas, sonolysis, photocatalysis, radiolysis, and supercritical water oxidation processes 3 7. However, newer approaches to achieve advanced oxidation

A novel green chemistry gelation method for polyvinyl pyrrolidone (PVP) and dimethylpolysiloxane (silicone): microwave-induced in-liquid-plasma

“…Unmistakably, the amount of PVP gel formed at pH ¼ 3 was signicantly greater than at pH ¼ 7, and more so than in alkaline media at pH ¼ 11. Earlier we discovered that the number of cOH radicals formed under MILP conditions in aqueous media increased with increase in pH, 12 which infers that the rate of decomposition of the PVP and/or the PVP gel exceeds the rate of formation of the gel at the higher pHs.…”

“…Accordingly, we were able to degrade fairly rapidly such pollutants as the persistent peruorooctanoic acid, 10 dyecontaminated wastewaters, 9 dioxane, 11 and the ame retardant tetrabromobisphenol-A in alkaline aqueous media. 12 The present study started from a completely unexpected discovery during an earlier study 13 in which our strategy was to synthesize silver nanoparticles using MILP to irradiate a 50 mL aqueous solution of silver nitrate for 5 min in the presence of polyvinyl pyrrolidone (PVP; a protective and reducing agent). At rst, the synthesis of Ag nanoparticles carried out with simple microwave heating, rather than MILP albeit under the same conditions, yielded a clear light brown aqueous solution due to plasmon absorption of the Ag nanoparticles (Fig.…”

“…Accordingly, we were able to degrade fairly rapidly such pollutants as the persistent perfluorooctanoic acid, 10 dye-contaminated wastewaters, 9 dioxane, 11 and the flame retardant tetrabromobisphenol-A in alkaline aqueous media. 12 …”