<p>Cadmium (Cd²⁺) is a highly toxic and carcinogenic heavy metal, even at trace concentrations, and poses serious health risks. Due to the extremely low permissible levels set by the World Health Organization (WHO) for drinking water, effective pre-concentration techniques such as solid-phase extraction (SPE) are essential prior to instrumental analysis. In this study, carbon spheres (CSs) were synthesized from sucrose using the oil-thermal method and evaluated as efficient adsorbents for the extraction and removal of Cd²⁺ from aqueous solutions. The synthesized CSs exhibited a uniform, spherical morphology with a high specific surface area of 375.5 m2&#xa0;g⁻¹. Maximum Cd²⁺ adsorption efficiency was observed at pH = 10 (71.25%), with a maximum adsorption capacity of 5.04&#xa0;mg&#xa0;g⁻¹. Adsorption data conformed well to the Langmuir isotherm model (R2 = 0.981) and the Dubinin–Radushkevich model. Kinetic studies indicated that the Elovich model provided the best fit (R2 = 0.995), reflecting a fast initial adsorption phase followed by gradual saturation. The presence of competing cations, particularly sodium ions, significantly reduced the adsorption efficiency—from 86.8% to 65.15% as Na⁺ concentration increased from 2 to 50&#xa0;ppm. Desorption studies demonstrated high recovery efficiency, with the highest elution yield (99%) achieved using 160 µL of 0.5 N HNO₃. Overall, the CSs synthesized from sucrose demonstrated promising performance as low-cost, high-efficiency adsorbents for SPE-based trace Cd²⁺ detection and removal. Their high surface area, strong affinity for Cd²⁺, rapid kinetics, and resistance to interference from competing ions highlight their potential for environmental monitoring and water treatment applications.</p>