## 7 Conclusions  
In this study, a low-cost adsorbent was prepared from rose geranium leaves carbonized at 600 \({}^{\circ}\)C and chemically activated using phosphoric acid to adsorb ibuprofen in an aqueous solution. Ibuprofen sorption on activated carbon from rose geranium leaves (AC-RGL) was compared with that of natural rose geranium leaves (Raw-GRL). The sorption processes on both adsorbents were evaluated using concentration, pH effect, time and temperature. The isotherms for the Raw-RGL and AC-RGL best fitted the Freundlich model, with a correlation coefficient ranging from 0.998 to 0.997, respectively. The adsorption kinetics was ascribed to the PFO model, with a regression coefficient of 0.995 for Raw-RGL and 0.993 for AC-RGL. The thermodynamic parameter (\(\Delta\)H\({}^{\circ}\)) for Raw-RGL and AC-RGL adsorbents indicated exothermic sorption processes. \(\Delta\)S\({}^{\circ}\) data for ibuprofen adsorption on both adsor  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Adsorbents**} & \multicolumn{2}{c}{**q(max) (mg/g)**} & \multirow{2}{*}{**References**} \\ \cline{2-2} \cline{4-3}  & **Ibuprofen** & \\ \hline Mesoporous carbon & 120.1 & [63] \\ Palm shell & 114.7 & [64] \\ Rose geranium leaves & 113.76 & This study \\ Standard activated carbon & 85.0 & [65] \\ Alkaline activated carbon & 68.0 & [66] \\ Yeast-based activated carbon & 51.0 & [67] \\ Leaves of mugwort weed & 16.95 & [68] \\ Sugarcane bagasse & 13.51 & [42] \\ Olive waste cake & 12.9 & [68] \\ \hline \hline \end{tabular}
\end{table}
Table 7: Uptake of ibuprofen using activated carbon-based adsorbents.  
Figure 13: FTIR spectra of Raw-RGL and AC-RGL adsorbents after adsorption.  
bents indicated increased randomness during adsorption. The negative figures (\(\Delta\)G\({}^{\circ}\)) for Raw-RGL and AC-RGL adsorbents indicated that the sorption process was feasible and spontaneous. The maximum adsorption capacity and removal efficiency of AC-RGL for removing ibuprofen were 113.76 and 74.12 mg/g for Raw-RGL. These results indicate that AC-RGL is an effective and efficient adsorbent for the sorption of ibuprofen.  
Conceptualization, P.M.T., P.N. and F.M.; methodology, P.M.T.; formal analysis, P.M.T.; investigation, P.M.T.; resources, P.N.; data curation, P.N.; writing--original draft preparation, P.M.T.; writing--review and editing, P.N.; supervision, F.M.; project administration, P.M.T. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Chincial clearance was obtained from the Faculty of Applied Sciences and Research Ethics Committee (FREC) of the Vaal University of Technology (VUT).  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The manuscript includes all the data used in this research and its findings.  
The corresponding author would like to acknowledge the support from Department of Chemistry, Vaal University of Technology, Vanderbijlpark, South Africa and collaboration from Cape Peninsula University of Technology, Cape Town, South Africa. All authors have consent to the acknowledgemnet.  
The authors have no conflict of interest.