*2.1. Sample Collection and Process*

The sample medium used in our laboratory was collected from the floodplain of the Yellow River in Mengjin District, Luoyang City, Henan Province. The sampling location is scoured by the Yellow River all the year round. As a result, the soil medium is relatively clean, and the background concentration of Pb is small, which has little influence on the laboratory experiment. Laboratory experiments need to separate sand into coarse medium and fine medium. The sample sand was collected and processed using the Technical Specification for Soil Environmental Monitoring's quarter method [31]. Then, the sample sand was dried and crushed in the laboratory. Finally, the sample was divided into three typical media, including coarse, medium, and fine sand in the pH range of 8.5–9.3 with an organic matter content range of 0.241–1.070 g·kg−1. The basic physical and chemical properties of the soil are shown in Table 1.

**Table 1.** Physical and chemical properties of soil.

