## 3 Results and Discussion  
### Characterization of Sorbents  
The results of the biochars characterization, including BET specific surface area (SSA), elemental composition, and surface morphology, are presented in Table 3 and Figure 1. The BET SSA of the investigated biochars varied between 61 and 111 m\({}^{2}\)/g, indicating differences in their surface areas and porosity. A higher SSA means a greater capacity for interaction between the biochar and contaminants. In Table 3, biochar derived from corn biomass has the highest SSA at 111 m\({}^{2}\)/g, indicating a highly porous structure with more surface available for adsorption. This high surface area is advantageous in adsorbing a greater volume of molecules, enhancing its performance in applications like capturing organic pollutants. In contrast, the lower SSA of biochar from hep (63 m\({}^{2}\)/g) and straw (61 m\({}^{2}\)/g) suggests that these biochars have fewer adsorption sites, making them less effective in processes where large-scale molecular interaction is required. The differences \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Model** & **Equation** & **Linear Form** & **Reference** \\ \hline [PERSON] & \(q_{e}=K_{F}C_{e}^{\alpha_{f}}\) & \(\log q_{e}=\log K_{F}+n_{F}\log C_{e}\) & [PERSON] [45] \\ [PERSON] & \(q_{e}=\frac{K_{C}}{1+a_{e}C_{e}}\) & \(\frac{C_{e}}{q_{e}}=\frac{a_{e}}{K_{e}}C_{e}+\frac{1}{K_{e}}\) & \\ [PERSON] & \(q_{e}=\frac{R_{F}}{1+n_{F}}\ln(A_{T}C_{e})\) & \(q_{e}=\frac{R_{F}}{b_{T}}\ln A_{T}+\frac{R_{F}^{2}}{b_{T}}\ln C_{e}\) & [PERSON] and [PERSON] [46] \\ [PERSON]–[PERSON] & \(q_{e}=q_{s}\exp(-B\epsilon^{2})\) & \(\ln q_{e}=\ln q_{s}-B\epsilon^{2}\) & \\ [PERSON]–[PERSON] & \(q_{e}=\frac{K_{C}a_{e}}{1+a_{e}C_{e}^{2}}\) & \(\ln\left[K_{R}\frac{C_{e}}{q_{e}}-1\right]=\ln\alpha_{R}+\beta\ln C_{e}\) & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mathematical models used for modeling data obtained in adsorption experiments. in SSA can be attributed to the distinct microstructures formed during the pyrolysis of each biomass, which can alter pore development. Porosity, which measures the internal void space within a material, is broken down into micropores (less than 2 nanometers in diameter) and mesopores (2 to 50 nanometers in diameter). These pore sizes play a critical role in determining the biochar's ability to adsorb molecules of varying sizes. Corn biochar has a micropore volume of 0.003 cm\({}^{3}\)/g and a mesopore volume of 0.014 cm\({}^{3}\)/g, indicating it has more small and medium-sized pores that contribute to its overall adsorption capacity. Micropores are highly efficient at adsorbing gases and small molecules due to their large surface area relative to volume, while mesopores are critical for adsorbing larger molecules, such as organic contaminants or dyes. The slightly larger pore radius of the straw biochar (28.5 A) suggests that it might be more suited for adsorbing larger molecules, albeit with less total surface area. The total pore volume of biochar, which reflects the combined volume of micropores and mesopores, further influences its adsorption capacity. Corn biochar, with a pore volume of 0.028 cm\({}^{3}\)/g, can trap a higher quantity of adsorbates compared to hemp and straw biochar, which have lower pore volumes (0.024 and 0.022 cm\({}^{3}\)/g, respectively). Thus, the high specific surface area and porosity of corn biochar make it a more effective adsorbent, especially in applications involving both small and large contaminants, whereas hemp and straw biochars may be better suited for specific, less demanding environments. Regarding the elemental composition, both biochars predominantly comprised carbon, ranging from 67% to 71%. This suggests that carbon is the major constituent of these biochars. However, the content of hydrogen, nitrogen, and sulphur was comparatively lower, indicating their minor presence in the biochars. [PERSON] et al.