## 3 Results
### Evaluation of Adsorption Capacity of CyP(Ph)4-DVB  
Determination of the sorption capacity (q\({}_{e}\)) by the batch method made it possible to assess the adsorption capacity of the synthesized CyP(Ph)4-DVB material and compare its properties with those of poly(DVB) and other adsorbents. For this purpose, three isotherm models, namely the Langmuir, Freundlich and Temkin models (Equations (2)-(4)) [51; 52], were used:  
\[\frac{C_{e}}{q_{e}}=\frac{1}{Q_{0}k_{L}}+\frac{C_{e}}{Q_{0}} \tag{2}\]  
Figure 8: Determination of pH\({}_{\text{PZC}}\) of the CyP(Ph)4 polymeric adsorbent. Figure 7: DSC curves of substrate 6 and obtained polymeric sorbents. \[log\ q_{e}=log\ k_{F}+\frac{1}{n}log\ C_{e} \tag{3}\]  
\[q_{e}=\left(\frac{RT}{b_{T}}\right)lnA+\left(\frac{RT}{b_{T}}\right)lnC_{e} \tag{4}\]  
where \(C_{e}\)--the equilibrium concentration of the dye in the solution (mg/L); \(Q_{0}\)--the monolayer adsorption capacity (mg/g); \(k_{L}\)--the Langmuir constant (relating to the free energy of adsorption) (L/mg); \(k_{F}\) (mg\({}^{1-1/n}\) L\({}^{1/n}\)/g) and \(1/n\)--the Freundlich constants concerning the adsorption capacity and the surface heterogeneity, respectively; \(R\)--the gas constant (8.314 J/mol K); \(T\)--the temperature (K); \(A\) (L/g) and \(b_{T}\) (J/mol)--the Temkin constants. Linear regression was applied to calculate the isotherm parameters from the \(C_{e}/q_{e}\) vs. \(C_{e}\), \(log(q_{e})\) vs. \(log(C_{e})\) and \(q_{e}\) vs. \(lnC_{e}\) plots. The fit of the isotherm equations to the experimental data was estimated taking into account the values of the determination coefficients R\({}^{2}\). Table 1 summarizes the obtained results. The Langmuir isotherm model describes adsorption on a homogeneous adsorbent surface with the formation of the monolayer in which the adsorbate particles, i.e., dyes, do not interact with each other. The values of R\({}^{2}\) were low and ranged from 0.438 to 0.880 for BY2 and BB3 adsorption on poly(DVB) and CyP(Ph)4-DVB, which rules out the Langmuir model to describe the experimental data. The Temkin isotherm model considers that the heat of adsorption of the chemical individuals in the layer decreases linearly as a result of increasing coverage of the adsorbent surface. The \(b_{T}\) values considering adsorption energy and calculated for the adsorption of the basic dye on the CyP(Ph)4-DVB and poly(DVB) were positive, which indicated that the adsorption of the dyes on the obtained adsorbents was exothermic. However, the R\({}^{2}\) values for the Temkin model, listed in Table 1, are lower than for the Freundlich model. The fitting results presented in Figure 9 indicate that the BY2 and BB3 adsorption process on poly(DVB) and CyP(Ph)4-DVB was a multilayer adsorption process, as the Freundlich model assumed. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Isotherm**} & \multirow{2}{*}{**Parameters**} & **poly(DVB)** & **CyP(Ph)4-DVB** & **poly(DVB)** & **CyP(Ph)4-DVB** \\ \cline{3-5}  & & & **BY2** & & **BB3** \\ \hline Langmuir & \(Q_{0}\) (mg/g) & 141.7 & 93.1 & 78.3 & 136.7 \\  & \(k_{L}\) (L/mg) & 0.03 & 0.19 & 0.42 & 0.77 \\  & R\({}^{2}\) & 0.549 & 0.653 & 0.438 & 0.880 \\ \hline \multirow{3}{*}{Freundlich} & \(k_{F}\) & \multirow{3}{*}{4.56} & \multirow{3}{*}{14.2} & \multirow{3}{*}{20.1} & \multirow{3}{*}{53.7} \\  & (mg\({}^{1-1/n}\)L\({}^{1/n}\)/g) & & & & \\ \cline{1-1}  & \(1/n\) & 0.91 & 0.63 & 0.64 & 0.76 \\ \cline{1-1}  & R\({}^{2}\) & 0.995 & 0.816 & 0.968 & 0.939 \\ \hline \multirow{3}{*}{Temkin} & \(A\) (L/mg) & 2.6 & 8.1 & 31.8 & 26.1 \\ \cline{1-1}  & \(b_{T}\) (J g/mol mg) & 294.3 & 207.1 & 335.2 & 131.0 \\ \cline{1-1}  & R\({}^{2}\) & 0.767 & 0.813 & 0.652 & 0.859 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Isotherm parameters determined for BY2 and BB3 adsorption on poly(DVB) and CyP(Ph)4-DVB. The R\({}^{2}\) values of the Freundlich isotherm model were higher (0.995 and 0.816 for BY2 adsorption, 0.968 and 0.939 for BB3 adsorption) than those of the Langmuir isotherm model.