## Results and Discussions
### FTWR Desorption Kinetic Analysis  
The pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to evaluate the desorption kinetics of RFTW on FTWR and study the possible mechanism of its desorption process. The correlated equations are as follows [39]. \[\ln\bigl{(}\mathrm{q_{e}-q_{t}}\bigr{)}=\ln\mathrm{q_{e}-k_{1}t} \tag{9}\]  
\[\frac{t}{\mathrm{q_{t}}}=\frac{1}{\mathrm{k_{2}}\mathrm{q_{e}}^{2}}+\frac{t}{ \mathrm{q_{e}}} \tag{10}\]  
\[\mathrm{q_{t}}=\mathrm{k_{i}t}^{1/2}+C \tag{11}\]  
where \(\mathrm{q_{e}}\) (mg/g) and \(\mathrm{q_{t}}\) (mg/g) represent the quantity of RFTW desorbed per unit mass of FTWR (g) at equilibrium and varying t (h), respectively. \(\mathrm{k_{1}}\) (h\({}^{-1}\)) and \(\mathrm{k_{2}}\) (h\({}^{-1}\)) are the pseudo-first-order and pseudo-second-order rate constants, respectively. C is a constant related to the thickness and boundary layer, and \(\mathrm{k_{i}}\) is the internal diffusion rate constant. The corresponding kinetic fitting parameters and correlated coefficients were listed in Table 10. The values of \(\mathrm{q_{e}}\), k and C can be determined by the slope and intercept of the fitted curve. It could be seen from Table 9 that the correlation coefficients R\({}^{2}\) fitted by the pseudo-first-order kinetic model are all less than 0.99, and the maximum desorption amounts when the desorption equilibrium is reached at 25-80 \({}^{\circ}\)C are 161.939, 238.333, 274.230, 316.496, and 329.212 mg/g, respectively. Both are less than the desorption amount in actual equilibrium. This showed that the desorption process of FTWR does not conform to the pseudo-first order kinetics. The correlation coefficients of the pseudo-secondary kinetic model fitting except for 50 \({}^{\circ}\)C (0.990), the R\({}^{2}\) of the other temperature fitting models are all greater than 0.99, and the maximum desorption capacity when the desorption equilibrium is reached at 25-80 \({}^{\circ}\)C are 183.453, 326.272, 323.090, 364.616, and 372.381 mg/g, respectively, are close to the actual experimental value. The results indicated that the pseudo-second-order kinetic model can better describe the desorption process, which indicated that there are adsorption-desorption saturation sites, and the reaction has multiple complex effects. Therefore, the internal diffusion model was used to continue the fitting. In Figure 7c, \(\mathrm{q_{t}}\) was plotted against t\({}^{1/2}\), and each temperature fitting line does not pass through the origin (intercept C = 0), which indicated that the internal diffusion was not controlled by a single rate. In Figure 7d, the internal diffusion model fitting graph can be fitted into three linear parts, and the fitting correlation coefficient R\({}^{2}\) is all greater than 0.9, which showed that the desorption of FTWR was divided into three stages: the desorption rate in the first stage was increased slowly; the desorption rate in the second stage was accelerated; and the desorption rate in the third stage was tended to be flat. The first stage was related to surface diffusion, \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Models** & **25 \({}^{\circ}\)C** & **50 \({}^{\circ}\)C** & **60 \({}^{\circ}\)C** & **70 \({}^{\circ}\)C** & **80 \({}^{\circ}\)C** \\ \hline q\({}_{\mathrm{eep}}\) (mg/g) & 183.5 & 326.3 & 323.1 & 364.6 & 372.4 \\ R\({}^{2}\) & 0.832 & 0.920 & 0.895 & 0.863 & 0.923 \\ pseudo-first-order & k\({}_{1}\) (h\({}^{-1}\)) & 1.656 & 0.811 & 1.310 & 1.584 & 1.811 \\ q\({}_{\mathrm{e}}\) (mg/g) & 161.9 & 238.3 & 274.2 & 316.5 & 329.2 \\ R\({}^{2}\) & 0.999 & 0.990 & 0.997 & 0.994 & 0.999 \\ pseudo-second-order & k\({}_{2}\) (h\({}^{-1}\)) & 0.012 & 0.003 & 0.005 & 0.006 & 0.007 \\ q\({}_{\mathrm{e}}\) (mg/g) & 184.5 & 324.7 & 322.6 & 363.6 & 370.4 \\  & R\({}^{2}\) & 0.946 & 0.945 & 0.967 & 0.978 & 0.951 \\ intraparticle diffusion model & K\({}_{1}\) (h\({}^{-1}\)) & 31.618 & 44.814 & 78.088 & 73.093 & 60.354 \\  & C & 104.939 & 112.194 & 130.953 & 186.918 & 220.907 \\ \hline \hline \end{tabular}
\end{table}