**4. Conclusions**

In the present study, the synthesized iron nanoparticles aided with natural waste material such as onion, moringa, tea waste, and potato were used as reduction and stabilization agents for the synthesis of iron nanoparticles and as an adsorbent for the treatment of wastewater. The synthetization of iron nanoparticles was confirmed by different characterization techniques such as EDX, XRF, FT-IR, XRD, and UV spectrum. The XRF and XRD pattern of the iron nanoparticles revealed a crystalline structure of the nanoparticles. The results illustrated that the synthesized adsorbent showed that iron magnetite aided with moringa and onion had a high efficiency than magnetite aided with potato and tea. The optimum conditions for the adsorption process were obtained with a contact time of 45 min and a dose of 0.4 g. Moreover, due to the favorable performance of onion and moringa in the removal of pollutants and its feasible separation from the aqueous solutions, it can be used as an efficient adsorbent in the treatment of water and wastewater; after conducting the necessary tests for the outlet samples of water after the treatment process, it was found that there were no negative effects on the water samples.

**Author Contributions:** Conceptualization, H.M.A. and M.A.E.-k.; methodology, H.M.A.; software, N.A.S.; validation, F.M.A.-H.; formal analysis, M.M.H.; investigation, H.M.A.; resources, H.M.A.; data curation, H.M.A.; writing—original draft preparation, H.M.A. and M.A.E.-k.; writing—review and editing, H.M.A. and M.A.E.-k.; visualization, H.M.A. and M.A.E.-k.; supervision, M.A.E.-k. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data is unavailable due to privacy or ethical restrictions.

**Conflicts of Interest:** The authors declare no conflict of interest.
