## 3 Results and Discussion
### Prediction of Adsorption Isotherm
The results show that, whether it is a high-concentration or low-concentration adsorbate, as long as the adsorption isotherm constant obtained by the adsorption experiment is used, the Langmuir and Freundlich models can be used to predict the removal efficiency of the adsorbent under different initial conditions. There will be no obvious errors in the results of the adsorption experiment [39]. Table 11 is a prediction of the required mass of adsorbents for the removal of high and low concentrations of chlorine-containing pollutants. If the mass (M) of the silica gel is 10 g, the initial solution volume (V) is 0.1 L, and the initial concentration of the TCE solute (C\({}_{0}\)) is 10.248 mg L\({}^{-1}\). When the removal percentage of the TCE by the silica gel reaches 67.26%, the mass of the silica gel predicted by Langmuir and Freundlich models is 10.24 and 10.20 g, respectively. Therefore, the error between the experimental value and the predicted value is 2.36% and 1.95%, respectively. Under the same conditions, if the initial concentration of PCE (C0) is 11.375 mg L\({}^{-1}\), when the removal percentage of the PCE by silica gel reaches 71.16%, the mass of silica gel predicted by the two models is 10.50 and 10.44 g, respectively. The error between the experimental value and the predicted value is 5.03% and 4.42%, respectively. For the prediction and error of the activated carbon mass required for low-concentration adsorbates, when the mass of activated carbon is 10 mg, the initial solution volume is 0.1 L, and the initial concentration of TCE is 1.0248 mg L\({}^{-1}\). When the activated carbon removal percentage of the TCE reaches 88.73%, the masses of activated carbon predicted by the [PERSON] and Freundlich models are 9.67 and 9.72 mg, respectively. The error between the experimental value and the predicted value is 3.24% and 2.84%, respectively. Under the same conditions, if the initial PCE concentration is 1.1375 mg L\({}^{-1}\), when the removal percentage of PCE by activated carbon reaches 92.1%, the masses of the activated carbon \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline \multicolumn{4}{p{56.9 pt}}{**(a) Silica Gel**} \\ \hline \multicolumn{4}{p{56.9 pt}}{**Initial Conditions**} & \multicolumn{4}{p{56.9 pt}}{**Predicted M (g)**} \\ \hline \(\textbf{C}_{0}\) (mg L\({}^{-1}\)) & **R (\%)** & **Experimental M (g)** & **Langmuir Isotherm** & **Error (\%) \({}^{*}\)** & **Freundlich Isotherm** & **Error (\%) \({}^{*}\)** \\ \hline TCE 10.248 & 67.26 & 10 & 10.24 & 2.36 & 10.20 & 1.95 \\ \hline PCE 11.375 & 71.16 & 10 & 10.50 & 5.03 & 10.44 & 4.42 \\ \hline \multicolumn{4}{p{56.9 pt}}{**(b) Activated Carbon**} \\ \hline \multicolumn{4}{p{56.9 pt}}{**Initial Conditions**} & \multicolumn{4}{p{56.9 pt}}{**Predicted M (mg)**} \\ \hline \(\textbf{C}_{0}\) (mg L\({}^{-1}\)) & **R (\%)** & **Experimental M (mg)** & **Langmuir Isotherm** & **Error (\%) \({}^{*}\)** & **Freundlich Isotherm** & **Error (\%) \({}^{*}\)** \\ \hline TCE 1.0248 & 88.73 & 10 & 9.67 & 3.24 & 9.72 & 2.84 \\ \hline PCE 1.1375 & 92.10 & 10 & 10.76 & 7.65 & 10.61 & 6.12 \\ \hline \multicolumn{4}{p{56.9 pt}}{* Note: Error = ( [ Experimental – Predicted ] )/Experimental \(\times\)100.} \\ \end{tabular}
\end{table} 
Table 11: Comparison of required adsorbent mass (M) predicted by Langmuir and Freundlich isotherms with mass balance to experimental data points obtained from the adsorption of TCE and PCE onto (a) silica gel and (b) activated carbon. predicted by the two models are 10.76 and 10.61 mg, respectively. The error between the experimental value and the predicted value is 7.65% and 6.12%, respectively. From the above experiments, it is found that, regardless of the adsorption of TCE and PCE by silica gel or activated carbon, the data obtained from the adsorption experiment or the removal efficiency predicted by the Langmuir and Freundlich models and the mass of the adsorbent have an error of less than 10%.