Ultrasonic degradation of acetaminophen in water: Effect of sonochemical parameters and water matrix

Abstract

This paper deals about the sonochemical water treatment of acetaminophen (ACP, N-acetyl-p-aminophenol or paracetamol), one of the most popular pharmaceutical compounds found in natural and drinking waters. Effect of ultrasonic power (20-60 W), initial ACP concentration (33-1323 μmol L(-1)) and pH (3-12) were evaluated. High ultrasonic powers and, low and natural acidic pH values favored the efficiency of the treatment. Effect of initial substrate concentration showed that the Langmuir-type kinetic model fit well the ACP sonochemical degradation. The influence of organic compounds in the water matrix, at concentrations 10-fold higher than ACP, was also evaluated. The results indicated that only organic compounds having a higher value of the Henry's law constant than the substrate decrease the efficiency of the treatment. On the other hand, ACP degradation in mineral natural water showed to be strongly dependent of the initial substrate concentration. A positive matrix effect was observed at low ACP concentrations (1.65 μmol L(-1)), which was attributed to the presence of bicarbonate ion in solution. However, at relative high ACP concentrations a detrimental effect of matrix components was noticed. Finally, the results indicated that ultrasonic action is able to transform ACP in aliphatic organic compounds that could be subsequently eliminated in a biological system.

Sonochemical Formation of Hydrogen Peroxide

“…For dimethyl phthalate, the degradation rate decreased somewhat with increasing pH across the 5-9 range [24]. Villaroel et al [20] reported that ultrasonic degradation of acetaminophen in more pronounced in an acidic medium than in basic aqueous solution. The influence of the pH of solutions is probably therefore due to the chemical structure and properties of the substance involved.…”

“…The influence of the pH of solutions is probably therefore due to the chemical structure and properties of the substance involved. Hydrophobicity of the pollutant has certainly been revealed as one of the most important factors [20,28]. In this study, the impact of H2O2 on the final amounts of hydrogen peroxide in solution was considered by reference to different H2O2 concentrations applied at the start of a sonication reaction.…”

“…The hydrogen peroxide is used in the decomposition and digestion of the substance present (DBP). In an aquatic solution, the formation of H2O2 and hydroxyl radicals caused by cavitation serves to destroy organic materials [20]. In uncontaminated water, hydrogen peroxide is not consumed.…”

“…During the past several years, ultrasound has been applied effectively as an emerging advanced oxidation process (AOP) for a wide variety of pollutants in wastewater treatment [12][13][14]. A growing number of studies have demonstrated that ultrasound irradiation results in a rapid and effective decomposition of phthalates [15], pesticides [16,17] phenols [18], chlorinated compounds [19], and pharmaceuticals [20] in aqueous solution. The main advantage is that the ultrasound process does not require added chemicals, oxidants or catalysts, and does not generate additional waste streams as compared with other processes (ozonation and adsorption).…”

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

“…In another study, the effect of power was reported at 600 kHz at four powers such as 20, 30, 40, 50 and 60 W for the degradation of acetaminophen. The degradation is found to be increased with increasing the applied power, and the maximum degradation is obtained at 60 W (Villaroel et al 2014). The degradation of atenolol is also reported by varying the power at three frequencies.…”