## 4 Conclusions  
Cost-effective and innovative adsorbents derived from date seeds (DAC) were effectively employed for the removal of heavy metals from aqueous solutions. This investigation explored the impact of factors such as adsorbent dose, pH, the presence and type of disinfectant, as well as the influence of dissolved organic matter (DOM), on the adsorption process. Scanning electron microscopy (SEM) images highlighted substantial changes in surface morphology pre- and post-adsorption. Key findings include the superior performance of date seed activated carbon (DAC) in removing heavy metals, notably Pb(II) and Cu(II). This study revealed a positive correlation between metal removal and increased adsorbent dosage for all three materials. Noteworthy trends emerged, such as higher copper ion removal at neutral pH (7) and lower removal under acidic conditions, while lead ions exhibited higher removal at acidic pH and reduced efficiency at pH 7. In the presence of monochloramine, both DACs exhibited exceptional Pb removal efficiency, nearing 100%. However, increasing the chlorine concentration from 2 to 4 ppm resulted in decreased Pb removal efficiency for DAC. Maximum lead removal was observed in the presence of 3 ppm of DOM by DAC with lower removal rates at 1 and 6 ppm DOM. SEM images further illustrated distinct morphological changes in the activated carbons before and after the adsorption process, providing visual insights into their structural transformations. Therefore, the findings of this study will be utilized in a wide variety of applications, including the purification of drinking water, the treatment of ground and municipal water, the reduction of gas emissions from power plants and landfills, and the recovery of precious metals. Even though the use of waste materials resolves concerns related to disposal, there may be concerns about the cost benefit of such a technology. The performance of date seed-derived activated carbon as an adsorbent is far superior to that of date seed in general. For this reason, the additional cost is justified by the benefits. The use of HCl and NaOH was minimal, indicating insignificant cost implications. In addition, there were no requirements for the removal of residual chloride or sodium. Previous studies suggested that AC can be regenerated and can be reused in a cost-effective way [83; 84]. Overall, even with the constraint of additional requirements, it still appears to be a cost-effective option. Future studies should also focus on optimizing the different factors affecting the activated carbon production from date seeds. **Author Contributions**: Conceptualization, M.S.R. and M.M. ; methodology, M.S.R. and N.B. ; validation, M.S.R., M.H.R. and M.M. ; formal analysis, M.S.R., M.H.R. and N.B. ; investigation, M.S.R. and N.B. ; writing--original draft preparation, M.S.R., M.H.R. and N.B. ; writing--review and editing, M.S.R., M.H.R. and M.M. ; visualization, M.S.R. and N.B. ; supervision, M.S.R. and M.M. ; project administration, M.M. ; funding acquisition, M.M. All authors have read and agreed to the published version of the manuscript. **Funding**: This research was funded by Sharjah National Oil Corporation grants for the American University of Sharjah, grant number 223215. The work in this paper was supported, in part, by the Open Access Program from the American University of Sharjah. **Institutional Review Board Statement**: Not applicable. **Informed Consent Statement**: Not applicable. **Data Availability Statement**: The data used and/or analyzed during the current study are available from the corresponding author upon reasonable request. **Acknowledgments**: The author wishes to express gratitude to [PERSON] from the Clean Technologies Research Institute at Dalhousie University for her technical assistance throughout the execution of SEM studies. The authors would like to recognize [PERSON] from the Mineral Resource Engineering Department at Dalhousie University for his contribution in preparing the activated carbon.