Ultrasonic cavitation applied to the treatment of bisphenol A. Effect of sonochemical parameters and analysis of BPA by-products

Abstract

Bisphenol A (BPA), a chemical compound largely used in the plastics industry, can end up in aquatic systems, which it disturbs by its endocrine disrupting effect (EDE). This study investigated the BPA degradation upon ultrasonic action under different experimental conditions. The effect of saturating gas (oxygen, argon and air), BPA concentration (0.15-460 micromol L(-1)), ultrasonic frequency (300-800 kHz) and power (20-80 W) were evaluated. For a 118 micromol L(-1)-BPA solution, with the best performance obtained at 300 kHz, 80 W, with oxygen as saturating gas. In these conditions, BPA can be readily eliminated by the ultrasound process (approximately 90 min). However, even after long ultrasound irradiation times (9 h), more than 50% of chemical oxygen demand (COD) and 80% of total organic carbon (TOC) remained in the solution. Analyses of intermediates using HPLC-MS investigation identified several products: monohydroxylated bisphenol A, 4-isopropenylphenol, quinone of monohydroxylated bisphenol A, dihydroxylated bisphenol A, quinone of dihydroxylated bisphenol A, monohydroxylated-4-isopropenylphenol and 4-hydroxyacetophenone. The presence of these hydroxylated aromatic structures showed that the main ultrasonic BPA degradation pathway is related to the reaction of BPA with the *OH radical. After 2h, these early products were converted into biodegradable aliphatic acids.

Sonochemical degradation of endocrine disrupting chemicals 17β-estradiol and 17α-ethinylestradiol in water and wastewater

“…In view of the increased demand for higher water quality standards without toxic by-product concerns, significant attention has been drawn to the use of ultrasound for treatment of pharmaceutical and personal care products in water and wastewater (Gogate and Pandit 2004;Naddeo et al 2009;Chiha et al 2011). This is because the generation of hydroxyl radicals through acoustic cavitations results in oxidative degradation of contaminants (Torres et al 2008). The cavitations involve the formation, growth and consequent collapse of micro bubbles, which occur in very short periods and release large amount of energy over a very small area (Gogate and Pandit 2002).…”

Removal of Endocrine Disruptors from Urban Wastewater by Advanced Oxidation Processes (AOPs): A Review

“…Conversely, experiments performed in natural water highlighted Fenton process inhibition, while ultrasound action was not hampered. Further studies from the same authors [44] proved that BPA ultrasonic degradation mainly occurs via free radicals oxidation and it is highly influenced by ultrasonic power: as power increases, the number of collapsing cavities also increases, leading to enhanced BPA degradation, as also found for other kinds of compounds [45].…”

Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration

“…Interestingly, the best performance was obtained during the UV/TiO 2 process, where more than 95% of DOC was removed after the treatment. In contrast, US showed zero mineralization despite total removal of DXC, suggesting that the pollutant transformed into stable by-products during sonochemical action (Torres et al, 2008). During the application of the sonochemical system, a pH reduction from 5.8 to 2.9 was observed as ).…”