# Innovative Vaporization of Wood Panel Waste into Activated Biochar for Efficient Phenol Adsorption
## 3 Results and Discussion  
### Characterization of Reconstituted Wood Panels, Biochar, and Activated Biochar  
The elemental, textural, and physicochemical analyses of wood panels and their components, as well as biochar and activated biochar, are comprehensively described in a recent study [46]. As illustrated in Figure 1, thermal activation of biochar results in substantial changes in the textural characteristics, such as increasing specific surface area (SBET) and total pore volume (Vt) with increasing temperature. Results show that raw biochar (BWP) has a low specific surface area (99 m\({}^{2}\)/g), which increases with temperature to values of 450, 682, and 866 m\({}^{2}\)/g after activation at 750, 850, and 950 \({}^{\circ}\)C, respectively. \begin{table}
\begin{tabular}{c c c c c} \hline
**Model** & **Type** & **Equation** & & **Description** \\ \hline Pseudo-first-order & Kinetic & \(\frac{d\omega}{dt}=k_{1}(q_{c}-q_{t})\) & & (2) & A first-order rate equation for adsorption describing rapid adsorption processes. Its linearized form is as follows: \\  & & & & \(\ln(q_{c}-q_{t})=\ln(q_{c})-\frac{k_{1}t}{2.80}\) & (3) \\ \hline Pseudo-second-order & Kinetic & \(\frac{d\omega}{dt}=k_{2}(q_{c}-q_{t})^{2}\) & & (4) & A second-order rate equation indicating a chemical or homogeneous adsorption mechanism. Its linearized form is as follows: \\  & & & & \(\frac{1}{q_{c}-q_{t}}=\frac{1}{k_{2}q_{2}}+\frac{t}{b}\) & (5) \\ \hline Langmuir & Isotherm & \(\frac{1}{q_{c}-q_{t}}=\frac{1}{q_{max}}+\frac{t}{B_{max}}C\epsilon\) & (6) & A monolayer adsorption model that assumes localized adsorption without interaction between adsorbate molecules. \\ \hline Freundlich & Isotherm & \(Log(q_{c})=Log(k_{f})+nLog(C\epsilon)\) & (7) & A model for heterogeneous adsorbent surfaces where \(K_{f}\) and \(n\) are coefficients describing the intensity and nonlinearity of adsorption. \\ \hline \multirow{2}{*}{[PERSON]} & Kinetic/chemical mechanism & \(\log(q_{c}-q_{t})=\log(q_{max})-\alpha.t\) & (8) & An equation that describes chemical adsorption, suitable for systems with heterogeneous surfaces. \\  & & & & A linear model in which the heat of adsorption decreases with molecular interactions, where k\({}_{1}\) is related to the heat of adsorption. \\ \hline \multirow{4}{*}{[PERSON]} & \multirow{4}{*}{Isotherm} & \multirow{4}{*}{\(q_{c}=k_{1}\ln(k_{2})+k_{1}\ln(c_{c})\)} & \multirow{4}{*}{(9)} & A linear model in which the heat of adsorption decreases with molecular interactions, where k\({}_{1}\) is related to the heat of adsorption. \\  & & & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & & & \\ \cline{1-1}  & & & & \\ \hline \end{tabular}
\begin{tabular}{c c c} \hline Where \(q_{t}\): adsorbed amount at equilibrium (mg/g); \(q_{t}\): adsorbed amount at any time \(t\) (mg/g); \(C\epsilon\): concentration of adsorbate at equilibrium (mg/L); \(C_{0}\): initial concentration of adsorbate (mg/L); \(k_{1}\), \(k_{2}\), \(k_{p}\), \(n\), \(\alpha\): specific constants for the models. \\ \end{tabular}
\end{table} 
Table 1: Summary of kinetic and adsorption isotherm models. These increases can be attributed to porosity development due to thermal degradation of volatile compounds and structural reorganization of amorphous carbon. Furthermore, the increased volume of micropores (V\(\upmu\)) and mesopores (Vm) indicates that thermal activation promotes the creation of additional adsorption sites, improving the material's ability to capture organic and inorganic contaminants in solution [47, 48]. This porosity development is essential for adsorption applications, as it increases surface interactions between the material and targeted molecules [49]. The strong correlation between increased specific surface area and improved adsorption performance has been confirmed in several studies of thermally or chemically activated biochars [50, 51, 52]. The elemental composition of activated biochar undergoes a series of changes in response to temperature variations.