Résumé
With the development of anthropological activities (agriculture, mining, industry) the number of polluted soil contaminated with heavy metals is constantly increasing and has become a global environmental problem. When heavy metals are present in the soil at too values, they disrupt the ecosystem and pose serious problems, which ultimately affect the health of both humans and animals. Conventional heavy metals remediation methods are based on physical, chemical, and biological approaches that can be applied directly in-situ or ex-situ (after excavation) but most of them are constrained by processing duration, high expenses, or secondary waste production.A new remediation method based on the combination of soil washing with the application of ultrasound has been developed recently [1]. This method was shown to improve extraction yields [2]. It may allow to operate in milder conditions [3].This study aims to decontaminate a soil artificially contaminated with three different heavy metals (copper, nickel and zinc) by leaching coupled with ultrasound, with a view to improving extraction yields and kinetics. The soil is first fully characterized and adsorption isotherms are measured. Decontamination is performed at 350 kHz with mechanical stirring (Fig. 1) and compared to silent conditions. Four different leaching agents have been tested: water, hydrochloric acid, citric acid and humic acid.