## 1 Introduction  
In recent decades, the large increase in anthropogenic operations, including industrial productions, mining activities, and fossil fuel extraction, has resulted in widespread environmental pollution. Such actions generate a pathway for the accumulation of many kinds of harmful substances and heavy metals into terrestrial and aquatic ecosystems, which consequently disturbs the biogeochemical balance of the ecosystem. When they are in their natural balance, such heavy metals do not present any significant contamination risk, but due to their toxic, persistent, and nondegradable nature, their continuous and excessive release into the environment results in severe environmental pollution, disrupts flora and fauna, and imperils human health [1; 2; 3]. Mining activities are linked to the discharge of many kinds of toxic heavy metals into the terrestrial and aquatic environment, causing black contamination of these natural resources, disturbing the landscape, and subsequently increasing soil degradation and making the soil unsuitable for agricultural practices [4; 5]. It is quite challenging to perform agricultural activities with heavy-metal-contaminated soils that are found in the vicinity of mining areas. In addition, plants grown in such contaminated sites were found to accumulate larger concentrations of hazardous heavy metals in their edible parts. Among these heavy metals, lead (Pb) ranks second after arsenic (As) in the list of hazardous heavy metals due to its potentially toxic nature and global manifestation [6]. The higher accumulation of Pb in the ecosystem severely affects the soil and water bodies, threatens plant growth and microbial activity, and poses a health risk to human beings, including abridged educational performance in children, truncated social skills, and inhibited physical activities among adults [7]. In addition to Pb, cadmium (Cd), which is usually released from mining activities and domestic wastes, is also classified as a hazardous heavy metal, which severally disturbs soil quality, interrupts plant growth, and poses serious human health risks, including kidney damage and bone fracture [8]. Restoration of such mining-contaminated soils to make them suitable for regular agricultural activities is extremely important to sustain environmental resources and to protect human health. Many kinds of physical, chemical, and biological techniques have been applied to rehabilitate such contaminated soils [9]. Metal stabilization and soil immobilization are key strategies by the application of chelating agents, solvent extraction techniques, thermally treating soil, and various soil amendments; adsorption is also a frequently practiced technique to remediate soils contaminated with heavy metals [10]. Most of these techniques are expensive, employ costly chemicals and excessive salts, and generate secondary pollution [11]. Recently, soil remediation with inorganic amendments and reactive minerals, such as carbonates, phosphate rocks, natural clay deposits, and zeolites, have gained desirable attention as a feasible and economical technique to reduce metal accumulation in soil without disturbing the soil's natural functions [12; 13]. Natural zeolites, which are found globally, have a three-dimensional silicon and oxygen tetrahedron lattice crystal structure and possess a unique structural composition and mineral contents [14]. An estimated 70 different kinds of natural zeolites have been discovered, and more than 250 different zeolites have been prepared synthetically [15]. Owing to their unique characteristics, such as promising physiochemical properties, easy availability, economic feasibility, and excellent adsorptive characteristics, natural zeolites have attained ample attention as an environmentally friendly material to stabilize and remove toxic heavy metals from soil and aqueous media [16] The structural properties and composition provide zeolites with great ion exchangeability, which subsequently results in the strong and selective adsorption of some specific metal ions.