## 3 Results and Discussion
### Adsorption Tests
#### 3.2.1 Organic Dyes Removal
Hence, the difference in pore size distribution can significantly affect the adsorption capacity for molecules of different sizes and shapes. For this reason, it is important to know the molecular dimensions of the pollutant adsorbate and ensure that the activated carbon used has sufficient pore diameter to achieve the removal of the adsorbate. Regarding the MB, EB, and BB molecules, they all have smaller molecular sizes (lower than 1.5 nm) compared with the average pore diameter of the active carbons used (Table 2). Figure 2: Removal rate (mmol/g of AC) during adsorption (min) for organic dyes and phenolic compounds. The reported data are the average of triplicate measurements; the standard deviations were always less than 5%. The adsorption time data for MB are reported until 25 min to see clearly the adsorption trend, because it is faster than the others. To meaningfully evaluate the performance of the sorbents, PC values have been calculated and reported in Table 6 together with breakthrough levels at 5%, 10%, and 50% of adsorption based on the adsorption isotherms. It is clear from the data reported in Table 6 that high adsorption capacities do not directly correlate to high PCs since the latter take into account also the residual concentration of pollutant. In general, the PCs of all the PACs considered are high for the dyes compared with the phenolic compounds, while the adsorption capacities have an opposite trend. An improvement in PC values implies enhancement in adsorption affinity: thus, the affinity of SCGs-AC for MB was significantly higher with respect C1-AC and C2-AC, in agreement with the surface properties of the ACs. Coherently, SCGs-AC exhibited a significantly lower affinity for EB and BB. The extremely high value of PC for C1-AC for BB could be considered in agreement with the extremely rapid adsorption rate observed in Figure 2. As for 3-chlorophenol (CP), the SCGs-AC shows both higher adsorption capacity (3765 mg/g) and partition coefficient (81.53 mg/g/uM) than the commercial PACs, representing and interesting candidate as compared with recent systems proposed in the literature (e.g., [PERSON] et al. [56] report for 2,4-dichlorophenol a maximum adsorption capacity of 45.95 mg/g and PC = 41.77 mg/g/uM). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample** & **Adsorption Time (min)** & **MB** & **EB** & **BB** & **Ph** & **CP** & **BPA** \\ \hline \multirow{4}{*}{SCGs-AC} & 5 & 100 & 46.3 & 27.2 & 60.6 & 85.4 & 14.9 \\  & 20 & 100 & 59.7 & 31.1 & 71.2 & 91.9 & 21.5 \\  & 60 & 100 & 73.8 & 34.4 & 71.3 & 94.8 & 29.3 \\  & 180 & 100 & 92.0 & 39.9 & 71.5 & 97.0 & 34.4 \\ \hline \multirow{4}{*}{C1-AC} & 5 & 80.8 & 62.7 & 96.0 & 52.4 & 78.3 & 23.1 \\  & 20 & 98.5 & 96.8 & 100 & 58.4 & 89.7 & 41.8 \\  & 60 & 100 & 100 & 100 & 59.4 & 93.5 & 58.5 \\  & 180 & 100 & 100 & 100 & 60.8 & 94.8 & 74.7 \\ \hline \multirow{4}{*}{C2-AC} & 5 & 97.8 & 51.4 & 43.4 & 56.3 & 87.5 & 10 \\  & 20 & 100 & 86.0 & 62.2 & 72.2 & 95.6 & 28.9 \\ \cline{1-1}  & 60 & 100 & 99.8 & 85.4 & 74.3 & 97.7 & 48.2 \\ \cline{1-1}  & 180 & 100 & 100 & 99.8 & 75.3 & 98.0 & 72.7 \\ \hline \hline \end{tabular}  
* The reported data are the average of triplicate measurements; the standard deviations were always less than 5%.  
\end{table} 
Table 4: Experimental adsorption capacity (%) of PACs at fixed time for organic dyes and phenolic compounds.\({}^{1}\)