A critical review on EDTA washing in soil remediation for potentially toxic elements (PTEs) pollutants

Soil pollution by potentially toxic elements (PTEs) is a serious threat to human health and ecosystem function. Soil washing using EDTA is one of the permanent disposal options available to remove PTEs from soil. Based on published studies, this paper summarized the current progress of remediation techniques using EDTA to mobilize and remove PTEs from contaminated soils. Firstly, the key factors to control EDTA washing were discussed, such as the concentration of EDTA, the pH of the washing solution, the washing time, multiple washing, and the liquid/solid ratio. Afterwards, the complicated changes in soil properties after washing were discussed. The change of soil properties is inevitable, so some measures need to be taken to reduce the damage to the soil by washing. Finally, the current improvements were summarized for the problems existing in the EDTA washing process. EDTA could be used in combination with other agents such as other chelating agents, reducing agents, acid compounds, and surfactants to improve efficiency of EDTA washing. The purpose of this paper is to provide a reference for further research and practical application of remediation of PTEs contaminated soil by EDTA washing. Graphic abstract: