Ultrasonic methods for effective soil remediation

Soil contamination presents significant remediation challenges due to the obstruction and adsorption effects of soil particles, which often constrain the efficiency of conventional remediation technologies. Therefore, developing innovative techniques to enhance soil remediation efficiency is of paramount importance. This review explores the application of ultrasound in soil remediation, highlighting its potential to address these challenges. Ultrasonic processes generate sonochemical effects, including cavitation, acoustic streaming, and thermal effects, which can directly facilitate soil remediation. Additionally, ultrasound enhances remediation efficiency by accelerating mass transfer and activating oxidants, thereby reducing remediation time. This paper reviews three key ultrasonic soil remediation technologies: Ultrasound-Soil Washing (US-SW), Ultrasound-Advanced Oxidation Processes (US-AOPs), and Ultrasound-Electrokinetic Remediation (US-EKR). It summarizes the mechanisms of ultrasonic soil remediation. Influential factors affecting these technologies are analyzed, and novel design concepts for ultrasonic reactors are proposed to advance the development of ultrasonic soil remediation techniques and overcome critical mass transfer limitations. Finally, it discusses the shortcomings of related studies and provides an outlook for future research. These advancements aim to improve the efficacy and practicality of ultrasound-based approaches for addressing soil contamination.