Ce was doped on TiO₂ nanoparticles (NPs), and this association was loaded on activated carbon (Ce-TiO₂-NPs-AC). The characterization was completed by FE-SEM, TEM, and XRD, and finally these NPs were used for the ultrasonic-assisted adsorption of Basic Red 46 (BR 46) from aqueous solution. An experimental model suggested by the central composite design (CCD)—as a branch of response surface methodology (RSM)—provides insight into the influence of variables, such as BR 46 concentration, pH, adsorbent mass, and sonication time, on BR 46 removal. Experimental results revealed that setting conditions at 25 mg L⁻¹ of BR 46, pH 5.0, 0.02 g of Ce-TiO₂-NPs-AC and 4 min sonication resulted in a high coefficient of determination (R² > 0.99) and low probability values. The difference in the values is likely due to the accumulation of more than 99% of BR 46, while equilibrium data described by Langmuir isotherm model with a high adsorption capacity of 58.61 mg g⁻¹ and adsorption process were successfully correlated with pseudo-second-order kinetics model.