## 3 Results and Discussion
### Adsorption Isotherms
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**Isotherm Parameters for Adsorption of RhB**} \\ \hline \multirow{2}{*}{**Isotherm**} & \multirow{2}{*}{**Parameters**} & \multicolumn{2}{c}{**Adsorbents**} \\ \cline{3-4}  & & **GO** & **GAC** \\ \hline \multirow{4}{*}{Langmuir} & \(\mathrm{q_{\mathrm{eep}}\ (mg/g)}\) & 673.5 & 419.8 \\ \cline{2-4}  & \(\mathrm{q_{\mathrm{p}red}\ (mg/g)}\) & 416.6 & 185.1 \\ \cline{2-4}  & \(\mathrm{B}\ (\mathrm{L}/mg)\) & 0.375 & 0.519 \\ \cline{2-4}  & \(\mathrm{R^{2}}\) & 0.842 & 0.719 \\ \hline \multirow{4}{*}{Freundlich} & 1/n & 0.452 & 0.368 \\ \cline{2-4}  & \(\mathrm{K_{\mathrm{F}}\ (L/mg)}\) & 107.1 & 60.2 \\ \cline{2-4}  & \(\mathrm{R^{2}}\) & 0.942 & 0.816 \\ \hline \multirow{4}{*}{Temkin} & \(\mathrm{K_{\mathrm{T}}\ (L/mg)}\) & 3.4 & 1.5 \\ \cline{2-4}  & \(\mathrm{B_{\mathrm{T}}\ }\) & 134.3 & 66.8 \\ \cline{2-4}  & \(\mathrm{R^{2}}\) & 0.854 & 0.625 \\ \hline \multirow{4}{*}{BET} & \(\mathrm{K_{\mathrm{b}}}\) & \(1.25\times 10^{8}\) & \(2.5\times 10^{6}\) \\ \cline{2-4}  & \(\mathrm{q_{\mathrm{p}red}\ (mg/g)}\) & \(8\times 10^{-4}\) & \(1\times 10^{-2}\) \\ \cline{2-4}  & \(\mathrm{R^{2}}\) & 0.919 & 0.969 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Isotherm parameters for adsorption of RhB with GO and GAC. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{3}{c}{**Isotherm Parameters for Adsorption of MB**} \\ \hline \multirow{2}{*}{**Isotherm**} & \multirow{2}{*}{**Parameters**} & \multicolumn{3}{c}{**Adsorbents**} \\ \cline{3-5}  & & **GO** & **GAC** & **NaY** \\ \hline \multirow{4}{*}{Langmuir} & \(\mathrm{q_{\mathrm{eep}}\ (mg/g)}\) & 475.0 & 609.8 & 97.0 \\ \cline{2-5}  & \(\mathrm{q_{\mathrm{p}red}\ (mg/g)}\) & 384.6 & 384.6 & 83.3 \\ \cline{2-5}  & \(\mathrm{B}\ (\mathrm{L}/mg)\) & 8.6 & 2.1 & 0.571 \\ \cline{2-5}  & \(\mathrm{R^{2}}\) & 0.840 & 0.919 & 0.612 \\ \hline \multirow{4}{*}{Freundlich} & 1/n & 0.186 & 0.237 & 0.338 \\ \cline{2-5}  & \(\mathrm{K_{\mathrm{F}}\ (L/mg)}\) & 190.5 & 190.5 & 40.73 \\ \cline{2-5}  & \(\mathrm{R^{2}}\) & 0.911 & 0.822 & 0.576 \\ \hline \multirow{4}{*}{Temkin} & \(\mathrm{K_{\mathrm{T}}\ (L/mg)}\) & 167.875.8 & 2402.8 & 65.7 \\ \cline{2-5}  & \(\mathrm{B_{\mathrm{T}}\ }\) & 42.1 & 65.4 & 25.3 \\ \cline{2-5}  & \(\mathrm{R^{2}}\) & 0.879 & 0.730 & 0.388 \\ \hline \multirow{4}{*}{BET} & \(\mathrm{K_{\mathrm{b}}}\) & \(5\times 10^{9}\) & \(5\times 10^{7}\) & \(10^{7}\) \\ \cline{2-5}  & \(\mathrm{q_{\mathrm{p}red}\ (mg/g)}\) & 0.0002 & \(1\times 10^{-2}\) & \(10^{-2}\) \\ \cline{1-1} \cline{2-5}  & \(\mathrm{R^{2}}\) & 0.966 & 0.876 & 0.615 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Isotherm parameters for adsorption of MB with GO, GAC, and NaY. (50 rpm). The removal efficiencies were in the order of GO > GAC > NaY for removal of RhB and GO \(\geq\) GAC > NaY for removal of MB. The results showed that GO had a higher removal efficiency compared to GAC (99.9 versus 86.6%), and a shorter equilibrium time (11 versus 5 days) for removing both MB and RhB, respectively. This demonstrates that GO effectively removes a larger range of contaminants than GAC. The large number of functional groups (epoxy and carboxyl) on GO surfaces was shown to exhibit multilayer behaviour and coverage of RhB and MB on its surface, which was well described by the Freundlich isotherm model. In addition, due to the multilayer structure of GO, it is hypothesized that this allows for a higher variation in pore size matrix and enhanced surface area, allowing for improved removal; further research is recommended. In contrast, NaY was unsuccessful in removing RhB, due to the highly organized structure and smaller pore sizes of this adsorbent. Given the limited studies on the robustness of commonly used adsorbents compared to synthetic adsorbents such as GO in removing synthetic dyes under equivalent conditions, further research should explore the potential of GO as a robust adsorbent for filter media in removing complex structured organic contaminants.