Table 3.

Key studies on the sonochemical degradation of surfactants.

Entry	Surfactant	Sonication conditions	Treatment’s effectiveness	Ref.
1	Triton X 100	358 kHz, 0.33 W/cm2, variable concentration (C0)	Higher removal degrees were recorded for concentration lower than the surfactant’s CMC (250 µM).	Destaillats et al. [40]
2	Teric GN9 (polydisperse nonylphenol ethoxylate surfactant)	363 kHz, 2 W/cm2, argon saturation, C0 = 0.01–0.11 mM	A remarkable TOC removal of nearly 90 % was attained after 24 h of sonication, underscoring the high mineralization process	Vinodgopal et al. [47]
3	sodium dodecylbenzenesulfonate (DBS) et sodium dodecylsulfate (SDS)	200 kHz, 6 W/cm2, argon/air atmospheres, C0 = 10 µM	More than 80 % removed within 1 h.	Yim et al. [29]
4	Sodium Dodecylbenzene Sulfonate (SDBS)	362 kHz, 2.5 W/cm2, C0 = 50–450 µM.	Significant degradation takes place, particularly when C0 is below the CMC of SDBS (∼150 µM).	Ashokkumar et al. [26]
5	Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)	200 kHz, 3 W/cm2, air and argon saturation, C0 = 10 and 100 mg/L	Effective removals were achieved, especially under an argon-sonicated medium	Moriwaki et al. [43]
6	4-octylbenzene sulfonate (OBS), dodecylbenzenesulfonate(DBS) and 4-ethylbenzene sulfonic acid (EBS)	354 kHz, 1.41 W/cm2, argon saturation, C0 = 0.1–5 mM	EBS and OBS exhibited faster degradation in the single-component system compared to their mixture counterpart.	Yang et al. [45]
7	perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS)	354 kHz (250 W/L), 500 kHz (150 W/L) and 618 kHz (250 W/L), argon saturation, C0 = 10 µM	Efficient removal, followed by immediate mineralization of the surfactants.	Vecitis et al. [25]
8	Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are	358 kHz, 250 W/L, argon saturation, 10 °C, C0 = 20 nM-200 µM	Both PFOA and PFOS efficiently degraded by ultrasound, especially for lower concentration	Vecitis et al. [27]
9	Octylbenzene Sulfonic Acid (OBSA)	206, 354, 620, 803, and 1062 kHz using pulse and continuous wave irradiation (CW, PW).	Sonication effectively degraded OBSA in either continuous or pulse irradiation	Yang et al. [55]
10	p-octylbenzene sulfonate (LAS C8), p-nonylbenzene sulfonate (LAS C9), and p-dodecylbenzene sulfonate (LAS C12)	200 kHz, 200 W, C0 = 15 to 2000 µM	Effective degradation of all LACs, especially at lower concentration level in the solution.	Nanzai et al. [54]
11	perfluorobutanoate (PFBA), perfluoro-butanesulfonate (PFBS), perfluoro-hexanoate (PFHA) and perfluorohexanesulfonate (PFHS)	202–1060 kHz (250 W/L), C0:0.30 µM for PFBS, 0.47 µM for PFBA, 0.23 µM for PFHS and 0.32 µM for PFHA, argon saturation.	Effective degradation was observed, and it decreased with an increase in the carbon number in the hydrophobic chain of the surfactants.	Campbell et al. [57]
12	Octaethylene glycol monododecyl ether (C12E8)	355 kHz, 18 W, C0 = 40 to 120 µM, 20 °C.	Effective degradation was observed, especially for concentration below CMC.	Singla et al. [45]
13	laurylpyridinium chloride (LPC)	355 kHz, 18 W (acoustic), C0 = 0.1 to 0.6 mM, 20 ± 5 °C	Effective treatment of LPC solution was achieved; however, a low removal of TOC was observed after an extended irradiation period of 20 h.	Singla et al. [128]
14	Octylbenzene sulfonate (OBS)	616 and 205 kHz (pulse and continues wave modes, PW,CW), 27 W acoustic, 20 °C; [OBS]0 = 1 mM.	OBS degraded efficiently under ultrasound. Continuous wave (CW) sonolysis showed improved degradation performance compared to the continuous wave mode.	Deojay et al. [56]
15	Perfluorobutyric acid (PFBA), Perfluorohexanoic acid (PFHA), perfluorooctanoate (PFOA), Potassium perfluorobutane-1-sulfonate (PFBS), potassium perfluorohexane-1-sulfonate (PFHS), and Potassium perfluoro- octane-1-sulfonate (PFOS)	202, 358 and 610 kHz for power densities of 83, 167, 250 and 333 W/L (argon atmosphere, C0: 300 nM for PFBS, 470 nM for PFBA, 230 nM for PFHS, 320 nM for PFHA, 200 nM for PFOS and PFOA)	Effective surfactant degradation occurs, with an optimum frequency of 358 kHz and applied power destiny of 333 W/L	Campbell and Hoffmann [58]
16	Perfluorooctane sulfonic acid (PFOS)	44, 400, 500 and 1000 kHz for 40 W power, C0 = 10 mg/L, pHi 5.66, air atmosphere	At elevated frequencies, over 90 % of PFOS was eliminated, whereas no degradation was evident at 44 kHz.	Wood et al. [66]
17	13 per- and polyfluoroalkyl substances (PFAS)	575 kHz and power density = 144 W/L, (temp.11 °C, pH 5.65)	Almost all compounds in the PFAS mixture experienced over 95 % degradation within 8 h.	Shende et al. [68]