Modeling perchloroethylene degradation under ultrasonic irradiation and photochemical oxidation in aqueous solution

Abstract

Sonolysis and photochemical degradation of different compounds such as chlorinated aliphatic hydrocarbons are among the recent advanced oxidation processes. Perchloroethylene is one of these compounds that has been mainly used as a solvent and degreaser. In this work, elimination of perchloroethylene in aqueous solution by ultrasonic irradiation, andphotochemical oxidation by ultra violet ray and hydrogen peroxide were investigated. Three different initial concentrations of perchloroethylene at different pH values, detention periods, and concentrations of hydrogen peroxide were investigated. Head space gas chromatography with FID detector was used for analyses of perchloroethylene. This research was performed in 9 months from April through December 2011.Results showed that perchloroethylene could be effectively and rapidly degraded by ultrasonic irradiation, photochemical oxidation by ultra violet ray, hydrogen peroxide and a combination of these methods. Kinetics of perchloroethylene was strongly influenced by time, initial concentration and pH value. Degradation of Perchloroethylene increased with decrease in the initial concentration of perchloroethylene from 0.3 to 10 mg/L at all initial pH. The results showed an optimum degradation condition achieved at pH = 5 but did not affect significantly the perchloroethylene destruction in the various pH values. Kinetic modeling applied for the obtained results showed that the degradation of perchloroethylene by ultrasound and photo-oxidation followed first order and second order model. The percentage of removal in the hybrids reactor was higher than each of the reactors alone, the reason being the role of hydroxyl radical induced by ultrasound and photochemical reaction.

Kinetics of degradation of perchloroethylene under ultra-sonic irradiation and photooxidation in aqueous solution

“…The dependence of degradation rate constants on initial concentration was similar to that in other studies [18,20,24]. In these studies, reaction mechanisms for the degradation of p-nitrophenol, carbon tetrachloride, parathion, p-nitrophenyl acetate, trinitrotoluene, perchloroethylene and monocyclic aromatic compounds in aqueous solution are investigated.…”

“…Air stripping, membrane processes and using of granular activated carbon are effective for removal of these compounds; but costly. Furthermore, they transfer the contamination to other parts of the environment [18]. Alternative technologies for degradation of chlorinated organic compounds include sonochemistry, photochemistry, electrochemistry, and combined treatment such as reductive dehalogenation and biodegradation [17].…”

“…Advanced oxida-tion processes (AOPs) are capable of degrading chlorinated organic compounds such as PCE in to less harmful compounds by using ultraviolet light. Ultrasonic waves are among the advanced oxidation processes which produce hydroxyl radicals during cavitations [18].…”

“…Although several studies are available on and sonolysis of pollutants, especially at low concentrations, few studies have addressed the PCE degradation by sonolysis and photooxidation (UVC) at micro-molar concentrations [17][18][19]. In this work, the degradation rates of PCE at different concentration levels and different pH levels with using an ultrasound bath at 130 kHz frequency and photooxidation with UVC ray and were studied.…”

Chlorpyrifos removal: Nb/boron-doped diamond anode coupled with solid polymer electrolyte and ultrasound irradiation

“…The removal efficiency of anodic oxidation could be enhanced by ultrasound irradiation. Indeed, recently sonochemistry has shown promising application in Focused Ultrasound Surgery (Ebbini and Ter Haar, 2015;Mihcin and Melzer, 2018;Morchi et al 2019), targeted drug delivery (Castle et al 2013;Dromi et al 2007;Ricotti et al 2015), proteomics (Jorge et al 2019(Jorge et al , 2018López-Ferrer et al 2008) and water treatment (Guo et al 2010;Homem and Santos, 2011;Kargar et al 2012;Tasca et al 2020;Villaroel et al 2014;Villegas-Guzman et al 2015). Sonochemical techniques are founded on the introduction of high-power ultrasound into the medium to be treated, alternating low-and high-pressure cycles.…”