# Facile Method by Bentonite Treated with Heat and Acid to Enhance Pesticide Adsorption
## 3 Results and Discussion
### Adsorption Isotherms
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Samples**} & \multicolumn{3}{c}{**[PERSON]**} & \multicolumn{3}{c}{**[PERSON]**} \\ \cline{2-7}  & \(\mathbf{q_{m}}\) & \(\mathbf{K_{L}}\) & \multirow{2}{*}{**R\({}^{2}\)**} & \multicolumn{2}{c}{**K\({}_{\text{F}}\)**} & \\ \cline{2-7}  & **(mg g\({}^{-1}\))** & **(L mg\({}^{-1}\))** & & & **(mg g\({}^{-1}\)).** **(L mg\({}^{-1}\))\({}^{1/n}\)** & **n** & **R\({}^{2}\)** \\ \hline B & 0.32 & 12.19 & 0.9968 & 1.26 & 4.32 & 0.9701 \\ BA\({}_{0.5}\) & 0.31 & 14.74 & 0.9976 & 0.96 & 3.06 & 0.9906 \\ BC\({}_{500}\) & 0.28 & 15.24 & 0.9972 & 1.17 & 3.06 & 0.9479 \\ BA\({}_{0.5}\)C\({}_{500}\) & 0.39 & 16.57 & 0.9925 & 0.58 & 1.80 & 0.9842 \\ BC\({}_{500}\)A\({}_{0.5}\) & 0.31 & 14.74 & 0.9986 & 1.22 & 3.70 & 0.9946 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: [PERSON] and Freundlich 2.4-D adsorption isotherm constants. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Samples**} & \multicolumn{3}{c}{**[PERSON]**} & \multicolumn{3}{c}{**[PERSON]**} \\ \cline{2-7}  & **q\({}_{\text{m}}\)** & \(\mathbf{K_{L}}\) & \multirow{2}{*}{**R\({}^{2}\)**} & \multicolumn{2}{c}{**K\({}_{\text{F}}\)**} & \\ \cline{2-7}  & **(mg g\({}^{-1}\))** & **(L mg\({}^{-1}\))** & & & **(mg g\({}^{-1}\)).** **(L mg\({}^{-1}\))\({}^{1/n}\)** & **n** & **R\({}^{2}\)** \\ \hline B & 3.18 & 1.01 & 0.9970 & 0.38 & 2.52 & 0.9822 \\ BA\({}_{0.5}\) & 6.37 & 0.52 & 0.9993 & 0.28 & 1.99 & 0.9563 \\ BC\({}_{500}\) & 4.52 & 2.05 & 0.9920 & 0.36 & 2.38 & 0.9795 \\ BA\({}_{0.5}\)C\({}_{500}\) & 5.22 & 0.53 & 0.9982 & 0.31 & 2.14 & 0.9651 \\ BC\({}_{500}\)A\({}_{0.5}\) & 15.87 & 3.64 & 0.9970 & 0.31 & 2.04 & 0.9902 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: [PERSON] and [PERSON] atrazine adsorption isotherm constants. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Samples**} & \multicolumn{3}{c}{**[PERSON]**} & \multicolumn{3}{c}{**[PERSON]**} \\ \cline{2-7}  & **q\({}_{\text{m}}\)** & \(\mathbf{K_{L}}\) & \multirow{2}{*}{**R\({}^{2}\)**} & \multicolumn{2}{c}{**K\({}_{\text{F}}\)**} & \\ \cline{2-7}  & **(mg g\({}^{-1}\))** & **(L mg\({}^{-1}\))** & & & **(mg g\({}^{-1}\)).** **(L mg\({}^{-1}\))\({}^{1/n}\)** & **n** & **R\({}^{2}\)** \\ \hline B & 0.17 & 31.71 & 0.9820 & 0.39 & 1.87 & 0.9703 \\ BA\({}_{0.5}\) & 0.88 & 8.01 & 0.9327 & 2.08 & 3.61 & 0.9668 \\ BC\({}_{500}\) & 1.92 & 5.05 & 0.9541 & 4.01 & 5.08 & 0.8312 \\ BA\({}_{0.5}\)C\({}_{500}\) & 1.24 & 7.41 & 0.9715 & 3.01 & 4.04 & 0.8983 \\ BC\({}_{500}\)A\({}_{0.5}\) & 1.19 & 6.38 & 0.9262 & 2.82 & 4.55 & 0.8886 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: [PERSON] and Freundlich diuron adsorption isotherm constants. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Samples**} & \multirow{2}{*}{**Temperature (K)**} & \multicolumn{3}{c}{**Langmuir Isotherm**} \\ \cline{2-7}  & **q\({}_{\text{m}}\) (mg g\({}^{-1}\))** & **K\({}_{\text{L}}\) (M\({}^{-1}\))** & **R\({}^{2}\)** \\ \hline Bentonite & 303 & 3.38 & 6.15 & 0.9915 \\  & 313 & 3.89 & 5.53 & 0.9964 \\  & 323 & 4.19 & 6.65 & 0.9990 \\ \hline BC\({}_{500}\)A\({}_{0.5}\) & 303 & 16.64 & 452.14 & 0.9992 \\  & 313 & 17.15 & 632.94 & 0.9995 \\  & 323 & 18.35 & 955.66 Enthalpy (\(\Delta\)H), entropy (\(\Delta\)S) and free energy (\(\Delta\)G) changes explain the thermodynamic data for the adsorption process, which were calculated by  
\[\Delta\mathrm{G}^{\circ}=-\mathrm{RTlnK_{L}} \tag{4}\]  
where R is the gas constant (8.314 J mol\({}^{-1}\) k\({}^{-1}\)); T is temperature (K) and K\({}_{L}\) is adsorption constant in the Langmuir isotherm.