## 4 Conclusions  
The composition analysis of carbon content reveals that a higher carbon content is formed in both the prepared and activated carbon contents due to H\({}_{3}\)PO\({}_{4}\) chemical reactions accomplished during the chemical activation process. H\({}_{3}\)PO\({}_{4}\) is used to speed up the process of breaking down bonds and strengthening cross-linking during the condensation process of activated carbon preparation. The Brunauer-Emmett-Teller (BET) surface area of the olive tree- and _Lantana camera_ activated carbon was 611.21 m\({}^{2}\)/g and 167.47 m\({}^{2}\)/g, respectively. The TGA analysis of both activated carbons shows their thermal degradation starts at 230 \({}^{\circ}\)C but fully degrades at temperatures above 450 \({}^{\circ}\)C. The production process of activated carbon from olive trees was examined using laboratory scale-data in order to estimate the associated environmental implications. One of the advantages of an LCA is that it can be used to develop a strategy for enhancing the AC production process while lowering the associated environmental impacts. The results demonstrated that chemical activation has the highest environmental impacts, followed by the drying and grinding/sieving steps. In terms of most of the impact categories addressed in this study, the chemical activation phase had the greatest environmental impact. The GWP was found to be 5.210 kg of CO\({}_{2}\) eq. The overall CED (70.521 MJ per kg) is split evenly across the grinding/sieving, chemical activation, and drying of the washed AC steps. The use of energy and other chemicals in the production of AC has been found to be environmentally detrimental. However, this laboratory-scale production procedure of AC might be different from the full industrial-scale process. Therefore, the LCA results should be interpreted carefully. Moreover, certain system improvements, such as the H\({}_{3}\)PO\({}_{4}\) recovery after AC washing, could result in extra savings. Further research is required to carry out the following tasks in order to reduce the environmental impact: first, the recovery of the generated phosphoric acid with the polluted water; and second, investigating the used olive tree AC regeneration after treatment for future life cycle assessment studies.  
Figure 6: Environmental impact of AC production process from olive trees.  
**Author Contributions:** Conceptualization, M.A., A.I. and H.H.S.; Formal analysis, M.A., H.H.S. and A.I.; Funding acquisition, A.I. and M.K.; Investigation, M.A. and A.I.; Methodology, M.A., Z.U.R.F., A.Z., M.K. and A.I.; Project administration, M.K.; Resources, M.A. and A.I.; Visualization, M.K. and A.I.; Writing--original draft, M.A. and A.I.; Writing--review & editing, H.H.S., Z.U.R.F., M.K. and A.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the pro quality grant provided by Silesian University of Technology, Gliwice, Poland under NAWA agency No. PPI/STE/2020/1/00016/U/0001 of 4 January 2021. (Nawa Ster Program).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors would like to acknowledge the pro quality grant provided by Silesian University of Technology, Gliwice, Poland under NAWA agency No. PPI/STE/2020/1/00016/U/00001 of 4 January 2021. (Nawa Ster Program).  
**Conflicts of Interest:** The authors declare no conflict of interest.