**4. Conclusions**

The adsorption experiments show that the argan shells used were very effective in removing emerging contaminants such as diclofenac and caffeine at relatively low concentrations in aqueous medium. Adsorption tests showed that the equilibrium time was 60 and 90 min for Dic and Caf, respectively. The adsorption of Dic and Caf on activated carbon (AC) from argan nutshells is perfectly described by a pseudo-second-order kinetic model. The highest adsorption capacity determined by the mathematical model of Langmuir was about 126 mg/g for Dic and 210 mg/g for Caf. The thermodynamic parameters

linked to the studied absorbent/adsorbate system show that the adsorption process is spontaneous and exothermic for diclofenac and endothermic for caffeine. Therefore, the chemical activation of argan shells improves its adsorption capacity. Thus, we can offer an adsorption material at low cost that can possibly contribute to the protection of the environment, especially in the purification of water. The valorization of Moroccan argan shells has been highlighted in this work.

**Author Contributions:** Conceptualization, B.B., D.C.-P. and F.E.M.; Funding acquisition, A.M.; Investigation, B.B., D.C.-P. and F.E.M.; Methodology, Y.E.Z., R.M., A.M., J.M.Q. and M.H.Z.; Supervision, Y.E.Z., A.M. and M.H.Z. 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:** Not applicable.

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