Sonochemical Remediation of Pollutants in Soils and Sediments

Abstract

Ultrasonic treatment serves as an alternative and/or complementary remediation technology for contaminated soils and sediments in comparison to traditional methods, such as dredging and in situ capping. Ultrasonic waves of alternating rarefaction and compression cycles create cavitation bubbles over the course of microseconds. Cavitational collapse produces enormous temperatures and pressures that initiate thermolysis of water and subsequent radical oxidation. Physical effects of ultrasound increase mass transfer rates, whether it be via desorption/dissolution of contaminants or solute transport in porous media. Both of these processes are integral in remediation. Desorption and dissolution ensure that contaminants are available for reaction in the aqueous phase. Increased solute transport by ultrasound enhances amendment delivery to contaminated sites. The purpose of this article is to describe both the potential for and challenges of utilizing ultrasound as a remediation technology. Much of this knowledge has been laid by the literature exploring the sonochemical effects on pollutants in bench‐scale sediment slurries. Both bench‐scale ultrasonic studies on remediation of contaminated soils and sediments and enhanced oil recovery using ultrasound have provided both mechanistic understandings and insights for pilot‐scale systems. Although challenges exist in scaled‐up systems, ultrasound is a multifunctional treatment technology with unique features compared to other remediation technologies.

Synergistic Removal of Cr(VI) with Stable Nanozerovalent Iron Particles and Ultrasound Assistance in the Presence of Organic Additives

“…For this, two alternatives of the combined NSTAR + US + Cit process can be proposed: (1) An NSTAR activation treatment faster (3 h) than the one suggested by the producer company (24–48 h), where NSTAR particles are suspended in an aqueous Cit solution and then irradiated with US, followed by injection of the activated NSTAR + Cit suspension; (2) Injection of the suspension of not activated NSTAR + Cit, followed by in situ application of US. Both procedures have been tested for soil remediation, but the treatment has still to be improved. , …”

In Situ EPR Spin Trapping and Competition Kinetics Demonstrate Temperature-Dependent Mechanisms of Synergistic Radical Production by Ultrasonically Activated Persulfate

“…Ultrasonically activated persulfate (US-PS) degrades various organic contaminants (e.g., pharmaceuticals and chlorinated solvents). − US-PS has been reported to degrade contaminants with faster rate constants ( k US‑PS ) than a linear combination of rates for individual technologies (eq ). ,− …”