## 1 Introduction
Although the radioactive waste in soil is readily removed by chemical treatment, it is economically unfavorable and has low remediation efficiency, which is infeasible for the remediation of large areas of radioactive contaminated soil [13]. Biological methods, including bioremediation with plants, generally have long remediation periods and are limited by highly selective plants [18]. Therefore, new methods are urgently needed to increase the economic benefits of radioactively contaminated soil decontamination. Recently, contaminated soil remediation through adsorption has been developed with various adsorbents [19]. Compared to the above-mentioned methods, adsorption through physical or chemical pathways has the advantages of high removal efficiencies, environmental safety, and favorable economics, and the adsorbents can be recycled and reused with magnetic separation processes. Zeolite with a general molecular formula of M\({}_{2}\)/nAl\({}_{2}\)O\({}_{3}\)\(\times\)SiO\({}_{2}\)\(\cdot\)yH\({}_{2}\)O is a porous hydrous aluminosilicate mineral with anionic framework structure, where M is a metal ion, usually Na+ and K+, n is the valence of the metal ion, x is the amount of SiO\({}_{2}\), and y is the amount of H\({}_{2}\)O. The composition of zeolites can be divided into A-type, X-type, Y-type zeolite, and mordenite based on the x value [20]. Furthermore, the silicon-oxygen tetrahedron or aluminum-oxygen tetrahedron of zeolite can be interconnected to form cavities and pores by more than 50% of the volume of the zeolite crystal with different shapes and sizes, resulting in a high surface area [21]. The adsorption capacity of zeolite can be activated and regenerated by heating. The highly porous structure of the zeolites can facilitate the adsorption of different kinds of molecules, depending on their molecule sizes. The different zeolites can absorb cations smaller than the micropores into the cavity while blocking cations larger than the pore size from adsorption, acting as a molecular sieve [20]. In addition, zeolite itself has good cation exchange performance, so zeolite exhibits unique selective adsorption characteristics for cations, which can be improved by pore modification [22]. Based on the above discussion, it is particularly important to detect and screen the appropriate raw materials to artificially design and synthesize proper zeolite adsorbent with a suitable pore size for the selective adsorption of Cs+ [23]. In the current study, a highly selective Cs+-magnetized zeolite adsorbent was prepared, and the adsorption capability was characterized with a laboratory-scale simulation, which will be detailed in the following section. The microstructure of the as-synthesized zeolite was characterized with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystallinity of the zeolite was determined with X-ray diffraction (XRD), while the magnetism was measured with magnetic hysteresis cycle analysis. The adsorbent was recovered and reused after decontaminating radioactive soil via magnetic separation with self-assembled magnetic recovery equipment. This technology significantly increased the soil decontamination efficiency while reducing secondary waste and recycling and reusing the adsorbent, which demonstrates promise for use in radioactive soil decontamination.