## 3 Results and Discussion
### Physical Adsorption of CS2 by Activated Carbon  
The adsorption configuration of CS2 on the activated carbon plane is illustrated in Figure 6a-c. The green interface between CS2 and activated carbon represents vdW forces, which are influenced by the ESP of the activated carbon plane. Consequently, the physical adsorption energy order of CS2 on the activated carbon plane can be observed as PR plane > NF plane > PD plane, as depicted in Table 2. Compared to the results calculated by [PERSON] et al. [41], our findings indicate a higher adsorption energy of CS2 on the PD plane, i.e., \(-0.231\) eV. This discrepancy can be attributed to our utilization of a larger activated carbon model, which effectively enhances the interaction area with CS2.  
Figure 5: IGMH analysis diagram depicting the adsorption of CH3 Cl on different activated carbon surfaces: (**a**,**d**) NF plane, (**b**,**e**) PD plane, (**c**,**f**) PR plane, and (**g**) PD edge. Atoms are colored by \(\delta\)Gatom. Bond critical points (orange spheres) and bond paths (brown lines) are also shown.  
Despite numerous geometric optimizations, a physical adsorption model of CS\({}_{2}\) on the PR edge remains elusive. Consequently, it can be inferred that the adsorption of CS\({}_{2}\) on the PR edge is difficult. Figure 6d shows that the interaction between CS\({}_{2}\) and NF involves a hydrogen bond formed by the S- and C-atoms of CS\({}_{2}\) with the H-atoms of activated carbon. Similarly, in Figure 6e, interactions between CS\({}_{2}\) and PD occur through hydrogen bonds and dipole-dipole interactions involving the S- and C-atoms of CS\({}_{2}\) and the H- and N-atoms of activated carbon, respectively. This result validates the findings of [PERSON] et al. that CS\({}_{2}\) adsorption mainly stemmed from physical adsorption, and a weak reversible chemical absorption peak was observed between C- and N-atoms in the infrared spectra [42]. Notably, the physical adsorption energy and electron density (as shown in Figure S3) at PD's edge surpass those at the NF's edge, indicating that pyridine functional groups facilitate CS\({}_{2}\) adsorption at activated carbon edges. Furthermore, comparing the energies of plane-to-edge adsorption reveals that CS\({}_{2}\) exhibits a greater affinity for being adsorbed onto activated carbon planes.  
The above description implies that the presence of the pyridine functional group enhances the adsorption of CH\({}_{3}\)Cl and CS\({}_{2}\) on the activated carbon edge, whereas the pyrrole functional group contributes to their adsorption on the activated carbon plane. This finding offers a pathway for designing highly efficient activated carbon materials tailored for CH\({}_{3}\)Cl and CS\({}_{2}\) adsorption. Research has demonstrated that melamine [40], urea-formaldehyde resin [43], nitric acid [44], and ammonia [16; 45] modifications enrich activated carbon surfaces with pyridine and pyrrole functional groups. Therefore, these modification methods can be used to enhance the adsorption effectiveness of CH\({}_{3}\)Cl and CS\({}_{2}\) on activated carbon.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **NF** & **PD** & **PR** \\ \hline Plane & \(-\)0.236 & \(-\)0.231 & \(-\)0.250 \\ Edge & \(-\)0.060 & \(-\)0.080 & — \\ \hline \hline \end{tabular}
\end{table}
Table 2: Physical adsorption energy (eV) of CS\({}_{2}\) on the plane and edge of activated carbon.  
Figure 6: IGMH analysis diagram depicting the adsorption of CS\({}_{2}\) on different activated carbon surfaces: (**a**) NF plane, (**b**) PD plane, (**c**) PR plane, (**d**) NF edge, and (**e**) PD edge. Atoms are colored by \(\delta\)Ga\({}^{\text{atom}}\). Bond critical points (orange spheres) and bond paths (brown lines) are also shown.