## 4 Micromechanics  
### Influence of Zeolite Doping on the Permeation of Bentonite-Based Liners  
(1) _XRD_  
From the adsorption test protocol for XRD tests, three samples were chosen. Figure 10 displays the XRD patterns under various test conditions. Under the condition of no zeolite, the intensity of the characteristic diffraction peak of montmorillonite decreased with the increase of the initial concentration of contaminants, which indicated that Zn\({}^{2+}\) would lead to the decrease of montmorillonite content; and there was a change in diffraction peak, which indicated that the adsorption test of Zn\({}^{2+}\) with bentonite produced new substances; according to the Bragg equation 2 dsin\(\theta\) = n\(\lambda\), the change of diffraction angle and the layer spacing also changed, which indicated that the interlayer of sodium-based bentonite Na\({}^{+}\) and Zn\({}^{2+}\) underwent ion exchange. The size of the interlayer hydrated cations determines \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \begin{tabular}{c} **Content/** \\ **Parameter** \\ \end{tabular} & \begin{tabular}{c} **Bentonite +** \\ **2 entonite** \\ \end{tabular} & \
\begin{tabular}{c} **Bentonite +** \\ **25\% Zeolite** \\ \end{tabular} &
\begin{tabular}{c} **Bentonite +** \\ **50\% Zeolite** \\ \end{tabular} \\ \hline \multirow{3}{*}{Langmuir} & K\({}_{\text{L}}\) & 3.55 \(\times\) 10\({}^{-4}\) & 3.54 \(\times\) 10\({}^{-4}\) & 3.02 \(\times\) 10\({}^{-4}\) & 2.45 \(\times\) 10\({}^{-4}\) \\  & q\({}_{\text{m}}\) & 145.90 & 181.80 & 253.60 & 423.40 \\ \cline{1-1}  & R\({}^{2}\) & 0.93 & 0.94 & 0.96 & 0.95 \\ \cline{1-1}  & K\({}_{\text{F}}\) & 0.51 & 0.42 & 0.39 & 0.33 \\ \cline{1-1} Freundlich & n & 1.60 & 1.46 & 1.33 & 1.25 \\ \cline{1-1}  & R\({}^{2}\) & 0.96 & 0.96 & 0.96 & 0.96 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters of adsorption model for mixed soils with a simultaneous variation of ZnCl\({}_{2}\) concentration and zeolite dopants. Figure 9: Fitting of adsorption models for mixed soils with simultaneous variations of ZnCl\({}_{2}\) concentration and zeolite dopants. (**a**) [PERSON] model; (**b**) Freundlich model. the spacing between both the montmorillonite layers, and the hydration capacity of metal cations is inversely proportional to their radius and inversely proportional to their charge. It is illustrated that the higher the ion concentration without zeolite admixture, the greater the permeability coefficient of the mixed soil. Zn\({}^{2+}\) is absorbed into the body by sodium-based bentonite, and because Zn\({}^{2+}\) carries a more significant charge than Na\({}^{+}\), the layer spacing increases, and the permeability of the bentonite weakens. Zeolite is incorporated, and the addition results in a new diffraction peak that is not the typical peak of zeolite composition, proving that zeolite is added throughout ion exchange. Interchange is generated by the exchangeable cations in the Zn\({}^{2+}\) and zeolite solution. This diminishes the amount of Zn\({}^{2+}\) ion exchange that takes place in solution with montmorillonite, weakening the detachment between bentonite layers, increasing bentonite expansion, and improving permeability, which is reflected in a reduction in the permeability coefficient of the mixed soil. (2) SEM  
Figure 11 shows a comparison of bentonite SEM images before and after zeolite incorporation under the action of the ionic solution. In a zoomed-in 10K SEM image, it can be seen that the zeolite addition of bentonite as a whole is a large piece of structure with a plume-like morphology, and bentonite indicates the emergence of plume-like colloid exfoliation traces by the solution; bentonite indicates that there is also cracking fragmentation of small particles, producing small flakes of montmorillonite, as shown in Figure 11a.