## 3 Results and Discussion
### Kinetic Parameters of Sorption
#### 3.2.2 Pseudo Second-Order Model
\begin{table}
\begin{tabular}{c c c c} \hline
**Sorbent** & **Kinetic Studies** & **Equilibrium Studies** & **Ref.** \\ \hline \multirow{4}{*}{Cotton fibre} & PSO, & & \\  & \(k_{2}=11.4\)\(\times\)\(10^{2}\)\(-\)\(12.95\)\(\times\)\(10^{2}\) g/mg min, & Langmuir model, & \\  & \(q_{e}=0.684\)–\(0.965\) mg/g, & & \\  & \(C_{0}=113.4\) mg/L, T = 40–90 \({}^{\circ}\)C, & & \\  & \(pH=7.03\), \(a.d.=1\) g/30 mL & & \\ \hline \multirow{4}{*}{Organoclay adsorbent} & PSO, & & \\  & \(k_{2}=0.087\) g/mg min, \(q_{e}=1.66\) mg/g, & & \\  & \(C_{0}=50\) mg/L, T = 25 \({}^{\circ}\)C, & & \\  & \(pH=3\), \(a.d.=0.2\) g/50 mL & & \\ \hline \multirow{4}{*}{Sugarcane bagasse biomass} & PSO, & & \\  & \(k_{2}=0.0051\) g/mg min, \(q_{e}=18.8\) mg/g, & & \\  & \(C_{0}=50\) mg/L, T = 30 \({}^{\circ}\)C, & & \\  & \(pH=2\), \(a.d.=0.05\) g/50 mL & & \\ \hline \multirow{4}{*}{Sugarcane bagasse biomass} & PSO, & & \\  & treated with & & \\  & polyethyleneimine & \(k_{2}=0.012\) g/mg min, \(q_{e}=20.7\) mg/g, & \\  & \(C_{0}=50\) mg/L, T = 30 \({}^{\circ}\)C, & & \\  & \(pH=2\), \(a.d.=0.05\) g/50 mL & & \\ \hline \end{tabular}
\end{table} 
Table 3: The kinetic and equilibrium parameters of DY50 sorption on various adsorbents based on the literature review. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Anion**} & \multirow{2}{*}{
\begin{tabular}{c} \(q_{e,exp}\) \\ **(mg/g)** \\ \end{tabular} } & \multicolumn{3}{c}{**[PERSON]**} & \multicolumn{3}{c}{**[PERSON]**} \\ \cline{2-9}  & \multirow{2}{*}{\(\mathbf{R^{2}}\)} & \multirow{2}{*}{\(\mathbf{Q_{0}}\)} & \(b\) & \multirow{2}{*}{\(\mathbf{R^{2}}\)} & \multirow{2}{*}{\(\mathbf{n}\)} & \multirow{2}{*}{\(\mathbf{1/n}\)} & \(\mathbf{k_{F}}\) \\  & & & & & & & \(\mathbf{(mg^{-1/n}\)}\) \\ \hline A24 & 666.5 & 0.998 & 652.9 & 0.0834 & 0.726 & 6.661 & 0.150 & 239.5 \\ A21 & 610.9 & 0.991 & 577.5 & 0.0460 & 0.308 & 3.526 & 0.284 & 84.3 \\ A23 & 284.3 & 0.990 & 290.3 & 0.0035 & 0.799 & 1.889 & 0.529 & 4.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The isotherm parameters determined from the Langmuir and Freundlich equations in the DY50-A21, DY50-A23 and DY50-A24 adsorption systems. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Sorbent** & **Kinetic Studies** & **Equilibrium Studies** & **Ref. ** \\ \hline Rice straw & \begin{tabular}{c} No model, \\ \(q_{e}\) = 2.8–1.0 mg/g, pH = 4–10, \\ \(C_{0}\) = 100 mg/L, \(t\) = 8 days, \\ \(a.d.=\) 0.5 mg/50 mL \\ \end{tabular}  & \begin{tabular}{c} Freundlich model, \\ \(k\) = 0.28–0.77 mg1\({}^{-1/n}\) L\({}^{1/n}\)/g, \\ \(n\) = 1.34–1.86, \\ pH = 4–10, \(a.d.=\)0.5 mg/50 mL \\ \end{tabular}  & \begin{tabular}{c} \\ \(k_{F}\) \\ \(\mathbf{(mg^{-1/n}\) L\({}^{1/n}\)/g}\) \\ \(n\) = 1.74–2.1, pH = 4–10, \\ \(a.d.=\)0.5 mg/50 mL \\ \end{tabular}  & [63] \\ \hline \multirow{2}{*}{ \begin{tabular}{c} \(\mathrm{R}^{2}\) \\ \(\mathrm{A}24\) \\ \(\mathrm{A}21\) \\ \(\mathrm{A}23\) \\ \end{tabular}  } & \begin{tabular}{c} No model, \\ \(q_{e}\) = 2.8–1.2 mg/g, pH = 4–10, \\ \(C_{0}\) = 100 mg/L, \(t\) = 8 days, \\ \(a.d.=\)0.5 mg/50 mL \\ \end{tabular}  & \ \begin{tabular}{c} Freundlich model, \\ \(k\) = 0.33–0.66 mg1\({}^{-1/n}\) L\({}^{1/n}\)/g, \\ \(n\) = 1.74–2.1, pH = 4–10, \\ \(a.d.=\)0.5 mg/50 mL \\ \end{tabular}  &
\begin{tabular}{c} \\ \(k_{F}\) \\ \(\mathbf{(mg^{-1/n}\) L\({}^{1/n}\)/g}\) \\ \(\mathbf{(mg^{-1/n