Ultrasonic application in contaminated soil remediation

Coupled high and low-frequency ultrasound remediation of PFAS-contaminated soils

“…Clay particles (<2 μm) were pipetted from 5 cm below the water surface after having settled for 24 h [66] , [67] , [68] , [69] . To measure the zeta-potential of the nanobubbles generated during the sonication process, the reactor chamber was filled with 1.5 L distilled water followed by ten minutes of sonication [48] , [70] , [71] . Samples were collected 5 min after sonication completed and zeta potential measurements were performed.…”

“…Acoustic cavitation, as driven by high-frequency ultrasound (between 500 kHz and 1000 kHz), is shown to be both an efficient and relatively fast method for the complete destruction and mineralization of PFOS and PFOA and is effective over a wide range of concentrations from 10 nM to 10 µM [41] , [42] , [43] , [44] . For a solid–liquid system, to date, most researchers have utilized low-frequency ultrasound for removal of contaminants (primarily hydrophobic compounds like PAHs and PCBs) from sediments [37] , [45] , [46] , [47] , [48] , [49] (see table S1 ). In these studies, the low-frequency ultrasound caused only sonophysical effects which serve in promoting the desorption of organic pollutants from solids, with little to no degradation of contaminants.…”

An effective thermal treatment of toluene-contaminated soil by uniform heating from microwave coupled infrared radiation (MCIR)

“…An orthogonal experiment was designed to investigate the influences of moisture content, microwave power, infrared power, and ultrasonic power, which were considered to be related to the contaminant removal. Some researchers consider ultrasound integrated with other technologies to gain better results (Effendi et al 2019); therefore, ultrasound was added to this part of the work to evaluate its effect. The results of the tests are shown in Table 2, along with the lab experimental sequence of each case.…”

Editorial overview: Green technologies for environmental remediation

“…Ultrasonic is an emerging technology that can be applied for the remediation of contaminated soil through two main mechanisms occurring in the ultrasonic process (desorption and chemical degradation). Although the research related to ultrasonic remediation is limited, ultrasonic could be used as a pre-treatment process or integrated with other remediation technology to improve the removal efficiency for organic and inorganic contaminants, especially heavy metals or petroleum hydrocarbon contaminated soil as shown by some studies [9]. Each of the above-mentioned mini reviews provide up to date published work on specific subject with a critical analysis of the technology.…”