<p>In this study, bentonite (BT), nanoscale zero-valent zinc-modified bentonite (BT-nZVZ), and carboxymethylcellulose-stabilized BT-nZVZ (BT-nZVZ-CMC) were synthesized for the removal of cadmium from aqueous solutions. Process optimization was conducted using the response surface methodology (RSM) based on the central composite design (CCD). Optimization experiments assessed the effects of several factors, including adsorbent dosage (0.5–2.5 g L⁻¹), solution pH (3–11), stirring time (20–100 min), and Cd²⁺ concentration (25–125 mg L⁻¹). The characterization results obtained from scanning electron microscopy with SEM–EDX, FTIR, and XRD confirmed the successful loading of nZVZ onto bentonite. The findings indicated that the BT-nZVZ-CMC adsorbent exhibited a significantly higher removal efficiency of 70% for cadmium from aqueous solutions compared to both BT and BT-nZVZ. Additionally, the RSM model, with an <i>R</i>² = 0.98, demonstrated a satisfactory correlation between the predicted values and the experimental results for cadmium removal. Optimization of the conditions revealed that the ideal parameters for cadmium removal using BT-nZVZ-CMC were a pH of 7, an initial Cd²⁺ concentration of 61 mg L⁻¹, a time of 78 min, and an adsorbent dosage of 2 g L⁻¹ and a desirability function of 1. The adsorption of Cd²⁺ onto BC-nZVZ-CMC was well described by the pseudo-second-order kinetic (<i>R</i>² &gt; 0.98) and Langmuir isotherm models (<i>R</i>² &gt; 0.99). BT-nZVZ-CMC showed the maximum adsorption capacity of 108.7 mg g⁻¹ for Cd²⁺. This study demonstrated the potential of BT-nZVZ-CMC as an efficient, stable, and economically viable adsorbent for the removal of cadmium from contaminated water.</p>