## 3 Results and Discussion
### Batch Adsorption Performance of EGS@APTES-GT
#### 3.2.3 Thermodynamic Study  
In environmental engineering practice, energy and entropy parameters must be considered to define process spontaneity and feasibility. Values of thermodynamic parameters are the crucial indicators for the evaluation of the practical application of the considered adsorbent. The values of Gibb's free energy (\(\Delta G^{\Theta}\)), the standard enthalpy change (\(\Delta H^{\Theta}\)), and the standard entropy change (\(\Delta S^{\Theta}\)) for the pollutant's adsorption onto EGS@APTES-GT at three temperatures (298, 308, and 318 K) were determined using equations (S18)-(S20) (given in SM S2.5). Hence, from the slope and intercept of plot In \(K_{\mathrm{L}}\) vs. \(1/T\), the values of \(\Delta H^{\Theta}\) and \(\Delta S^{\Theta}\) were obtained and, together with the calculated \(\Delta G^{\Theta}\) value, are given in Table 3. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**adsorbent** & **Pollutant** & **Conditions** & \(q_{\bullet}\) **(mg g\({}^{-1}\))** & **Isotherm** & **Ref.** \\ \hline FeOOH immobilized on the biodegradable root powder & As(V) & & C\({}_{\mathrm{L}}\) = 10 ppm, & & \\ biodegradation root powder & As(V) & & T = 30 °C, & \\  & & pH = 9.0, & & \\  & & m/V = 18 L\({}^{-1}\) & & & \\ \hline Goehlite-impregnated fly ash & As(V) & & C\({}_{\mathrm{L}}\) = 5 ppm, & & \\  & (FAG) & As(V) & T = 45 °C, & & \\  & & m/V = 0.22 \(\mathrm{g\,L}^{-1}\) & & & \\ \hline Magnetic-impregnated fly ash & As(V) & & C\({}_{\mathrm{L}}\) = 5 ppm, & & \\  & (FAM) & As(V) & T = 45 °C, & 19.1 & Langmuir & [51] \\  & & & m/V = 0.22 \(\mathrm{g\,L}^{-1}\) & & & \\ \hline (a) & Magnetic & & C\({}_{\mathrm{L}}\) = 20 ppm, & (a) & 91.2 & \\ (b) & NC-MA/L-MG & As(V) & T = 45 °C, & (b) & 85.3 & \\  & MC-O/NC-L-MG & & pH = 6.0 \(\pm\) 0.1, & (c) & 18.5 & \\  & & & m/V = not given & & \\ \hline (a) & Iron-based adsorbent & & C\({}_{\mathrm{L}}\) = 5 ppm, & & \\  & from mine waste & & T = - & (a) & 50.38 & Langmuir \\  & (MIRESCOR) & As(V) & pH = 6.6, & (b) & 29.07 & Freundlich & [57] \\ (b) & Granular ferric & & m/V = 0.01–10 g & & \\  & hydroxide (GFH) & & L\({}^{-1}\) & & & \\ \hline (a) & Recycled geothetic (BT9) & & C\({}_{\mathrm{L}}\) = 10 ppm, & & \\ (b) & Recycled geothetic + & As(V) & T = room, & (a) & 28.25 & Langmuir \\  & MnO\({}_{2}\) (MnBT9) & & PH = 3.5, & (b) & 25.71 & Freundlich & [58] \\ \hline \multirow{7}{*}{Cell-MG hybrid membrane} & & & C\({}_{\mathrm{L}}\) = 6.1 ppm, & & \\  & & T = 25 °C, & & & \\  & & pH = 6.0, & 35.3 & & \\  & & m/V = 0.11–11.11 g & & & \\  & & L\({}^{-1}\) & & & \\ \hline (a) & Magnetic sugarcane & & C\({}_{\mathrm{L}}\) = 5.1 ppm, & & \\  & bagase (MBo) & & T = 25 °C, & & \\  & (MgNe) & & m/V = 0.11–11.11 & & & \\  & & & L\({}^{-1}\) & & \\ \hline \multirow{7}{*}{Expanded Glass Spheres & & & C\({}_{\mathrm{L}}\) = 4.83 ppm, & & \\  & & T = 25 °C, & & \\  & & pH = 7.0 \(\pm\) 0.1, & & \\  & modified with APTES and & & m/V = 0.1–1.0 g L\({}^{-1}\) & & \\ \cline{1-1}  & & & C\({}_{\mathrm{L}}\) = 9.81 ppm, & & \\ \cline{1-1}  & & & T = 25 °C, & & \\ \cline{1-1}  & & & pH = 7.0 \(\pm\) 0.1, & & \\ \cline{1-1}  & & & m/V = 0.1–1.0 g L\({}^{-1}\) & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison within other adsorbents. The negative values of \(\Delta G^{\Theta}\) indicate the spontaneity of the adsorption process, while a positive \(\Delta H^{\Theta}\) confirms the favorable adsorption onto EGS@APTES-GT with the increase in the operative process temperature. The disruption of water hydration spheres and the transport of pollutant species through the bulk solution, within the pores, and through the surface boundary layer is a slightly more intensive process for Iprodione removal at higher temperatures. This effect is of higher significance for the EGS@APTES-GT/As(V) system. The positive value of \(\Delta H^{\Theta}\) shows the endothermic nature of the process and the positive value of \(\Delta S^{\Theta}\) indicates an increase in randomness at the solid-liquid interface.