eng Science and Education Publishing Journal of Materials Physics and Chemistry 2333-4444 2026-06-26 14 1 11 21 10.12691/jmpc-14-1-2 JMPC20261412 article Bi Gamy Ars¨¨ne Tra arsenetrabi86@gmail.com 1 2 Drissa Bamba 2 Alfred Niamien Kouam¨¦ 2 Namory M¨¦it¨¦ 2 Mariame Coulibaly 2 Koffi L¨¦on Konan 2 Samuel Oyetola 2 Laboratory of Constitution and Reaction of Matter (LCRM), UFR SSMT, F¨¦lix Houphou?t-Boigny University, Abidjan, Ivory Coast This study aims to evaluate the effects of a combined treatment involving calcination at 750°C, acid activation, and ferrihydrite doping on the physicochemical, mineralogical, and morphological properties of three natural clays from Côte d'Ivoire (KR, KB, and BB). To this end, physicochemical characterizations were performed on the raw samples, after calcination, and after ferrihydrite modification, in order to assess the influence of these treatments on the properties of the materials. The results indicate that calcination induces the transformation of kaolinite into amorphous metakaolinite, thereby enhancing structural disorder and promoting the formation of new reactive sites. Acid activation leads to an increase in porosity through the partial dissolution of aluminous phases, while ferrihydrite doping enriches the materials with iron oxyhydroxides and increases the density of surface hydroxyl groups. These modifications resulted in a significant improvement in the textural properties of the clays, with specific surface areas reaching 87.32 m² g?¹ and iodine numbers as high as 1373 mg g?¹. Overall, the ferrihydrite-modified samples, particularly KR-Fe and KB-Fe, exhibited the most pronounced improvements in their physicochemical and textural characteristics, highlighting the potential of this modification strategy for the future development of low-cost materials for water treatment applications. https://pubs.sciepub.com/jmpc/14/1/2/jmpc-14-1-2.pdf Modified clays Ferrihydrite Physicochemical properties Adsorption