<p>A nanocomposite consisting of <i>Cordia africana</i>-derived activated carbon (CAAC), acid-activated red clay (AARC), and magnetite (Fe₃O₄) was developed for efficient hexavalent chromium (Cr (VI)) removal from aqueous solutions. While materials such as red clay, magnetite, and activated carbon have individually been explored for Cr (VI) remediation, these previous studies often suffer from limitations such as low adsorption capacity, poor reusability, slow kinetics, and limited selectivity. To overcome these drawbacks, we have combined these materials into a nanocomposite that takes advantage of the synergistic effects of each component. A dual optimization approach, incorporating One Factor at a Time (OFAT) and Response Surface Methodology (RSM), was used to assess the impact of five parameters: pH, contact time, adsorbent dose, mixing speed, and initial Cr (VI) concentration. OFAT identified optimal ranges for these factors, which were refined using RSM to maximize Cr (VI) removal. Under optimized conditions, the nanocomposite achieved 99.9% Cr (VI) removal. Characterization revealed significant changes in surface area post-adsorption, confirming effective Cr (VI) interaction. Adsorption data fit the Langmuir isotherm (<i>R</i>² = 0.996) and pseudo-second-order kinetic model (<i>R</i>² = 0.971), indicating monolayer adsorption and chemisorption. The material also demonstrated excellent reusability, retaining high performance after seven regeneration cycles using NaOH and HNO_₃ with magnetic separation. Compared to existing adsorbents, the CAAC/AARC/Fe_₃O_₄ nanocomposite addresses key limitations such as enhanced adsorption capacity, faster kinetics, improved reusability, and greater selectivity for Cr (VI), offering valuable insights for sustainable wastewater treatment.</p>