Intensification of sonochemical degradation of ammonium perfluorooctanoate by persulfate oxidant

Abstract

Ammonium perfluorooctanoate (APFO) is an emerging environmental pollutant attracting significant attention due to its global distribution, high persistence, and bioaccumulation properties. The decomposition of APFO in aqueous solution with a combination of persulfate oxidant and ultrasonic irradiation was investigated. The effects of operating parameters, such as ultrasonic power, persulfate concentration, APFO concentration, and initial media pH on APFO degradation were discussed. In the absence of persulfate, 35.5% of initial APFO in 46.4 μmol/L solution under ultrasound irradiation, was decomposed rapidly after 120 min with the defluorination ratio reaching 6.73%. In contrast, when 10 mmol/L persulfate was used, 51.2% of initial APFO (46.4 μmol/L) was decomposed and the defluorination ratio reached 11.15% within 120 min reaction time. Enhancement of the decomposition of APFO can be explained by acceleration of substrate decarboxylation, induced by sulfate radical anions formed from the persulfate during ultrasonic irradiation. The SO4(-•)/APFO reactions at the bubble-water interface appear to be the primary pathway for the sonochemical degradation of the perfluorinated surfactants.

Sono-activated persulfate oxidation of bisphenol A: Kinetics, pathways and the controversial role of temperature

“…The same trend appears to occur for the experiments without temperature control although reaction rates are generally lower for the reasons given in Section 3.2. Other studies have also confirmed the positive effect of increasing SPS concentration on the sonochemical degradation of humic acid [23] and perfluorooctanoic acid [24] although excessive concentrations may have an adverse effect since sulfate radicals can scavenge themselves and/or SPS [25].…”

“…Hao et al [25], who studied the sonodegradation of ammonium perfluorooctanoate in the presence of SPS in the pH range 2-13, found that the maximum rate was achieved at pH = 6 but it decreased at lower or higher values.…”

“…Persulfate conversion to sulfate radicals does not occur spontaneously but it must be catalyzed by transition metals [15,16] or activated by quinones [17], heat [18,19], microwaves [20] and ultraviolet radiation [21,22]. Alternatively, this can be achieved by the use of ultrasound as has been demonstrated in recent studies concerning the aqueous phase degradation of humic acid [23], perfluorooctanoic acid [24], ammonium perfluorooctanoate [25], trichloroethane [26], dinitrotoluenes [27] and amoxicillin [28], as well as the remediation of soils contaminated with PAHs [29].…”

Sonochemical Degradation of Rhodamine B Using Oxidants, Hydrogen Peroxide/Peroxydisulfate/Peroxymonosulfate, with Fe2+ Ion: Proposed Pathway and Kinetics

“…As like the H 2 O 2 the PMS and PDS were reported to produce radicals, which will enhance the oxidation reaction (Maruthamuthu and Neta, 1977;Fernandez et al, 2004;Zhao et al, 2010;Chen et al, 2012;Olmez-Hanci and Arslan-Alaton, 2013;Hao et al, 2014). The study of experiments with the additions of PMS and PDS will further increase the degradation efficiency of RB and may enlighten the location of degradation of RB that is in the bulk liquid medium.…”

Effect of surfactants on the degradation of perfluorooctanoic acid (PFOA) by ultrasonic (US) treatment

“…Some of these methods additionally utilize hydroxyl radicals to remove pollutants, which have been noted in the literature to be largely inefficient at degrading PFOA due to their relative inactivity [16,17]. Ultrasonic (US) treatment produces micro-plasma via the cavitation phenomenon and is an effective method of destroying organic pollutants and removing PFOA specifically [16,[18][19][20]. This method does not only produce high temperature micro-plasma due to the collapse of tiny vapor bubbles produced by ultrasound, but also leads to in situ pyrolytic reactions in the vapor and interfacial regions of each collapsing bubble resulting in the breakdown of water producing radicals, such as hydroxyl radicals, oxygen atoms and hydrogen atoms [21][22][23].…”