ABSTRACT Cadmium and other heavy metals in landfills pose significant health and environmental risks due to their leaching potential into soil and groundwater when in contact with water or moisture. In this study, we synthesised two composites, composite I (C(I)) and composite II (C(II)), using Algerian clay and coconut shell-derived activated carbon. These composites are intended for controlled landfill waste management. The components are mixed at varying mass percentages, effectively adsorbing cadmium (Cd2+) from aqueous solutions. We conducted a parametric adsorption study using an experimental design. Cd2+ removal is more effective with composite C(II), reaching a Qmax of 163 mg.g−1 and an improved R of 59% at 25°C, while C(I) achieves a Qmax of 131 mg.g−1 and an R of 47%. The pH study indicated significant adsorption in the pH range [6–8]. The experiment utilised a screening design to optimise Cd2+ adsorption and establish the response surface. The coded variable Xi ranged from −1 (low) to + 1 (high) such as pH (X1: 2–6), temperature (X2: 25–45°C), composite mass (X3: 0.5–2.5 g.L−1), stirring speed (X4: 20–180 Oscillation/min), equilibrium time (X5: 60–120 min), and initial solution concentration (X6: 25–225 mg.L−1). The optimal values for X1, X4, and X6 were found to be 6, 180 Oscillation/min, and 185 mg.L−1, respectively.