## 3 Results and Discussion
### Adsorption Isotherms
\begin{table}
\begin{tabular}{l l l l l l l} \hline \hline \multirow{3}{*}{**Adsorbents**} & \multicolumn{4}{c}{**Freundlich Model**} \\ \cline{2-7}  & \multicolumn{4}{c}{} & \multicolumn{4}{c}{\(logK_{\mathbf{d}}\)} \\ \cline{2-7}  & \(R^{2}\) & \(\mathbf{N}\) & \(\begin{array}{c}K_{\mathbf{f}}\\ (\upmu\text{g/g})/(\upmu\text{g/L})^{\upmu}\end{array}\) & \(\mathbf{0.015_{w}}\) & \(\mathbf{0.15_{w}}\) & \(\mathbf{0.55_{w}}\) \\ \hline BC1 & 0.906 & 0.422 & 122 & 6.178 & 5.600 & 5.196 \\ \hline BC2 & 0.997 & 1.22 & 0.292 & 0.111 & 0.185 & 0.265 \\ \hline BC3 & 0.988 & 0.513 & 31.3 & 5.414 & 4.927 & 4.587 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Parameters of [PERSON]’s adsorption model for both investigated biochars. Figure 5: Adsorption isotherms of 4-MBC on biochar from (**a**) corn, (**b**) hemp, and (**c**) straw. confirm the nonlinearity of adsorption, indicative of heterogeneous binding sites on the surface of the sorbent. The Dubinin-Radushkevich (D-R) model was also applied to gain further insight into the adsorption mechanisms of MPs. The calculated free adsorption energy values (E\({}_{\text{a}}\)) for the interaction of 4-MBC with the selected MPs ranged from 0.3 to 63.2 kJ/mol. For PEg and PET, the low E\({}_{\text{a}}\) values (0.3-0.4 kJ/mol) suggest that the adsorption is primarily driven by physisorption, involving hydrophobic interactions, \(\pi\)-\(\pi\) stacking, and van der Waals forces. Physisorption typically results in weaker, reversible adsorption, which may be  
Figure 6: Adsorption isotherms of 4-MBC on (**a**) PEg, (**b**) PET, (**c**) PP, and (**d**) PLA particles obtained for the synthetic matrix. \begin{table}
\begin{tabular}{l l l l l l l l l l l l l l l l} \hline \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{\begin{tabular}{l} **[PERSON]** \\ **Model** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{l} **[PERSON]** \\ **Model** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{l} **[PERSON]** \\ **Model** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{l} **[PERSON]-** \\ **[PERSON]** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{l} **[PERSON]** \\ **Model** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{l} **[PERSON]** \\ **Model** \\ \end{tabular} } \\  & & & & & & & & & & & & & & & & \\ \cline{2-19}  & \(K_{\text{g}}\) & \((\text{\mu g}/\text{\mu g}/\text{\mu g}/\text{\mu g})\) & \(R^{2}\) & \(\text{\begin{tabular}{l}}K_{\text{L}}\text{ \\ **(L/\text{\mu g})** \\ \end{tabular} }\) & \(\text{\begin{tabular}{l} **qmax** \\ **(\text{\mu g}/\text{\mu g})** \\ \end{tabular} }\) & \(R^{2}\) & \(\text{\begin{tabular}{l}}K_{\text{R}}\text{ \\ **(L/\text{\mu g})** \\ \end{tabular} }\) & \(\beta\) & \(R^{2}\) & \(\text{\
\begin{tabular}{l}}K_{\text{B}}\text{ \\ **(L/\text{\mu g})** \\ \end{tabular} }\) & \(\text{
\begin{tabular}{l}}B_{\text{L}}\text{ \\ **(L/\text{\mu g})** \\ \end{tabular} }\) & \(R^{2}\) \\ \hline PEg & 2.94 & 0.45 & 0.956 & 0.42 & 9.36 & 0.973 & 5.12 & 0.853 & 0.967 & 6.283 & 0.4 & 0.953 & 1306.8 & 5.26 & 0.958 \\ PET & 9.32 & 0.50 & 0.895 & 1.54 & 16.6 & 0.961 & 21.5 & 1.00 & 0.910 & 3.44 & 0.3 & 0.953 & 685.4 & 15.4 & 0.956 \\ PP & 7.41 & 0.34 & 0.880 & 2.46 & 12.1 & 0.980 & 28.8 & 1.00 & 0.972 & 0.0003 & 43.2 & 0.970 & 1014.0 & 27.6 & 0.969 \\ PLA & 3.29 & 0.15 & 0.977 & 12.5 & 4.30 & 0.778 & 213.3 & 0.87 & 0.982 & 1.24 & 63.4 & 0.896 & 4944.0 & 928.9 & 0.982 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Values of the Freundlich, Langmuir, Redlich–Peterson, Dubinin–Radushkevich, and Temkin model parameters for the sorption of 4-MBC on PEg, PET, PP, and PLA. advantageous or limiting depending on the intended application (e.g., in pollutant removal, weaker adsorption could lead to easier desorption and release back into the environment). Conversely, the higher E\({}_{\text{a}}\) values for PP and PLA (>8 kJ/mol) suggest a chemisorption mechanism characterized by stronger, often irreversible bonds, such as covalent bonding or ion exchange.