Application of fxed bed column for separation of gadolinium and neodymium ions from their aqueous solutions using cyphos IL-104 impregnated silica was investigated. The performance of separation of the two lanthanide elements was evaluated by determining the column capacity, the total quantity sorbed of metal ions, and the removal percentage. These indicative column performance parameters were evaluated in altered conditions including fxed bed height of 2.0 and 3.0 cm, fow rate of 1.0 and 2.0 mL/min, and solution feed concentration of 50 and 100 ppm. Breakthrough modeling of the sorption process across the column was performed by employing Thomas and Adams–Bohart models. It was found that it took less time to reach the breakthrough when the fow rate and initial concentration increased, while the height of the bed decreased. Also, the column capacity increased by increasing the bed depth, decreasing the fow rate, and increasing the initial metal ion concentrations. 0.1 M nitric acid was found to be the best media for the separation of Nd3+ and Gd3+ ions.