###### Abstract  
Bentonite is frequently utilized as a landfill lining material due to its high impermeability. Due to the fact that heavy metal ions in leachate can alter the permeability of bentonite liner, the impermeability and metal adsorption effect of bentonite liner is typically enhanced by the use of external admixtures. In this investigation, zeolite was combined with stone chips and bentonite. Using a flexible wall permeation test, zeta potential test, and X-ray diffraction test, the effect of zeolite on the permeability and adsorption properties of the mixture was investigated. The results indicate that the addition of zeolite can enhance the impermeability of the mixed soil. The permeability coefficient of the mixed soil in DIW is 3.74 \(\times\) 10\({}^{-7}\) cm/s when bentonite is incorporated at 11% and decreases to 6.55 \(\times\) 10\({}^{-8}\), 4.65 \(\times\) 10\({}^{-8}\), and 5.10 \(\times\) 10\({}^{-8}\) cm/s when 12.50%, 25%, and 50% of zeolite are incorporated; the permeability coefficient of the mixed soil in DIW was 3.74 \(\times\) 10\({}^{-7}\) cm/s when the permeate concentration was 0.01 mol/L of ZnCl\({}_{2}\) solution, the permeation coefficients were 5.73 \(\times\) 10\({}^{-7}\), 5.98 \(\times\) 10\({}^{-8}\), 5.8 \(\times\) 10\({}^{-8}\), and 5.7 \(\times\) 10\({}^{-8}\) cm/s when the zeolite doping was 0, 12.50, 25, or 50%, respectively, and the Zn\({}^{2+}\) concentration of the leachate decreased compared to the no-zeolite case by 92.48, 97.29, and 98.65%, respectively; the competitive adsorption of metal ions by zeolites in ionic solutions of different concentrations reduced the ionic concentration in the solution and decreased the inhibition of bentonite swelling, while the adsorption characteristics of stone chip-bentonite-zeolite mixture on Zn\({}^{2+}\) were measured by the [PERSON] et al. model. s 2022 2022 12 11732 2022 11732 2022211732 2022211732 2022211732 2022211732 2022211732 2022211732 2022211732 2022211732 2022211732 202211732 2022211732 202211732 202211732 20221173  
capacity. Through adsorption tests, [PERSON] et al. [9] indicated that Zn\({}^{2+}\) adsorption by bentonite increases with increasing initial ion concentration. [PERSON] et al. [10] found that the adsorption of metal ions by bentonite is affected by the solution pH; Sodium-based bentonite dosage, contact time, and temperature were found to be highly influenced. In addition, bentonite has some excellent physicochemical properties, including a large specific surface area, chemical stability, low cost, high porosity, and ubiquitous availability [11]. Based on these benefits, there is a significant amount of space for further investigation into the application of bentonite for the adsorption of heavy metal ions in landfills. The swelling properties and permeability characteristics of bentonite are affected when it encounters heavy metal ions [12]. This is mainly due to the fact that the free swelling of bentonite gradually decreases with increasing ionic valence and concentration in solution [13], leading to a gradual increase in the permeability coefficient of bentonite. The effect of ion concentration on the permeability coefficient is the dominant factor at lower (\(\leq\)0.01 M) or higher (\(\geq\)1 M) ion concentrations [14]. In order to reduce the influence of heavy metal ions on the permeability of bentonite, the influence of heavy metals on the swelling properties of bentonite is generally reduced by the addition of adsorbents, and zeolite is one of the more commonly used additives [15]. [PERSON] [16] found experimentally that the adsorption capacity of zeolites for metal ions strongly depends on the initial metal ion concentration. [PERSON] et al. [17] found that both natural zeolite and bentonite have better adsorption properties for metal Zn\({}^{2+}\) in controlled tests. [PERSON] et al. [18] showed by the results that the addition of 66.67%, 29.17%, and 4.16 wt.% zeolite, bentonite, and kaolin, respectively, can optimize the adsorption capacity of the mixture for metal ions simultaneously.