Recent advances in the treatment of contaminated soils by ball milling technology: Classification, mechanisms, and applications

Soil pollution has become an important environmental issue worldwide. Various pollutants in soils may harm human health through the food chain. At present, the commonly used remediated methods mainly include thermal treatment, electrokinetic remediation, stabilization/solidification, soil washing, and bioremediation. Among them, ball milling is a non-combustion technology with simple operation, green, and mild reaction conditions as well as wide applicability, and it is promising in the decontamination of soil pollutants. Ball milling techniques have been gradually used for the detoxification of persistent organic pollutants and heavy metals in contaminated soils, while related reviews focusing on ball milling for soil remediation are limited. It is necessary to fully understand the potential and applied value of ball milling for remediation of contaminated soils. Ball milling has different effects and mechanisms for different pollutants and soil types. Therefore, there is a need to systematically review and digest the relevant knowledge on ball milling remediation of contaminated soils. In this review, the main types of ball milling and influencing factors are summarized, and the mechanisms of ball milling for soil remediation are analyzed. Finally, the problems which need to be solved are briefly described and the future research direction and trend are pointed out. This review is expected to promote the application and its in-depth research of ball milling technology on soil remediation.