Ultrasound‐Assisted Soil Washing for Metals‐Contaminated Soil Using Various Washing Solutions

Abstract

AbstractBench‐scale soil washing experiments with and without ultrasound‐assistance are conducted to remove potentially toxic metals (PTMs) from contaminated soils by using artificially contaminated soil samples. Three washing solutions including distilled water, oxalic acid, and citric acid are tested for their efficacy in the removal of PTMs. Ultrasonication time and concentration of the extracting agents are considered as factors affecting the removal efficiency while the mechanism of removal is explored by studying the chemical species of PTMs before and after washing. The results indicate that ultrasound could have significant enhancement on the efficiency of soil washing. Moreover, analysis of the metallic species shows that the removal efficiency is dependent on the type of species. In general, more obvious enhancement of the removal efficiency is detected in the carbonate‐bound and Fe/Mn oxide‐bound fractions of lead, whereas for cadmium, it is for the carbonate‐bound, Fe/Mn oxide‐bound, and organic‐bound fractions compared to four different other forms of the metallic elements.