## 5 Conclusions  
The adsorption of Pb(II) ions from an aqueous solution using lignocellulosic waste such as cassava peels, banana peels, yam peels, and oil palm bagasse revealed promising results for the application of such materials on the treatment of wastewater. The ultimate, proximate, and FTIR analyses showed that the structures of the adsorbents were characteristic of lignocellulosic materials. The characterization techniques of BET, SEM, and EDS revealed the mesoporous characteristics of all biomasses, as well as, high carbon and oxygen contents. EDS and FTIR analyses confirmed the precipitation of Pb on the evaluated adsorbent materials. The highest removal yields were achieved by the CP biomass (98.19%),  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Model** & **Parameter** & **CP** & **YP** & **BP** & **OBP** \\ \hline \multirow{3}{*}{Pseudo-first order} & \(q_{\mathrm{c1}}\) (mg/g) & 17.79 & 19.82 & 19.54 & 19.92 \\  & \(k_{1}\) (min\({}^{-1}\)) & 249.37 & 1.53 & 1.276 & 0.38 \\  & R\({}^{2}\) & 0.996 & 0.943 & 0.932 & 0.945 \\ \hline \multirow{3}{*}{Pseudo-second order} & \(k_{2}\) (g/mg+min) & 1662.33 & 0.13 & 0.15 & 0.224 \\  & \(q_{e}\) (mg/g) & 17.79 & 19.97 & 19.68 & 19.97 \\ \cline{1-1}  & R\({}^{2}\) & 0.999 & 0.967 & 0.978 & 0.976 \\ \hline \multirow{3}{*}{Elovich} & \(\alpha\) (mmol-g\({}^{-1}\)-min\({}^{-1}\)) & 2,070,197,227 & \(2.47\times 10^{98}\) & \(2.39\times 10^{87}\) & \(1.90\times 10^{107}\) \\  & \(\beta\) (g/mg) & 1.48 & 11.78 & 11.56 & 12.78 \\ \cline{1-1}  & R\({}^{2}\) & 0.853 & 0.898 & 0.896 & 0.898 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Fitting parameters for kinetic models.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Model** & **Parameter** & **CP** & **YP** & **BP** & **OBP** \\ \hline \multirow{3}{*}{Langmuir} & \(q_{max}\) (mg/g) & 11.79 & 98.36 & 18.96 & 99.73 \\  & \(C_{f}\) (L/g) & 7,246,598.09 & 0.16 & 724,09 & 0.05 \\  & R\({}^{2}\) & 0.713 & 0.985 & 0.824 & 0.954 \\ \hline \multirow{3}{*}{[PERSON]} & \(K\) (mg/g) & 9.57 & 13.42 & 14.78 & 8.38 \\  & n & 0.242 & 0.86 & 0.376 & 1.87 \\ \cline{1-1}  & R\({}^{2}\) & 0.972 & 0.999 & 0.982 & 0.835 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Fitting parameters for isotherm models.  
followed by the BP (90.12%), which may be attributed to their irregular morphologies, small pore size, and high surface area. For the OPB biomass, novel chemical configurations must be considered to increase the adsorption capacity. The fitting of adsorption data to the Freundlich isotherm model and pseudo-second order kinetic indicated that Pb(II) adsorption obeyed chemical reactions, and that most of the process occurs within the multilayered pores.  
[PERSON], [PERSON] and [PERSON] conceived and designed the paper, and wrote the Introduction and Materials and Methods. [PERSON] and [PERSON] wrote the Results and prepared figures and tables. Discussions and Conclusions were the collective work of all authors. The writing-review & editing was performed by [PERSON].  
This research was funded by University of Cartagena with the grant of _\"Vicinevestigaciones\"_ Program and The APC was also funded by University of Cartagena.  
Authors would like to thank University of Cartagena for proving the chemicals and equipment required to successfully conclude this work.  
The authors declare no conflict of interest.