Composite copper–ceria-based adsorbent prepared by different sol–gel and co-precipitation methods and their performances were examined for cadmium removal from aqueous solution. Cadmium as a pollutant in drinking water is a severe problem that has negative health effects on humans. In the present study, the prepared adsorbents were characterized using a particle size analyzer, BET surface area, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analysis. TEM analysis revealed the presence of approximately hexagonal-shaped copper oxide ceria with size ranging from 15 to 20 nm and having an average size distribution of 15.45 nm for sol–gel and 16.79 nm for co-precipitation prepared adsorbents. Synthesized adsorbents obtained using the sol–gel method showed better cadmium removal than those obtained using co-precipitation methods. Adsorption data of adsorption isotherm and kinetic models were analyzed. Cadmium’s adsorption was more rapid in the sol–gel copper oxide ceria adsorbent compared to the co-precipitation copper oxide ceria adsorbent. Equilibrium was attained quickly because of the higher surface area of CuO/CeO2 prepared by the sol–gel method. The equilibrium adsorption capability of sol–gel copper oxide ceria was more than 93%, while the co-precipitation copper oxide ceria’s equilibrium adsorption capability was approximately 89%. The prepared copper–ceria composite adsorbents showed good performance toward cadmium removal from aqueous solutions.