The isotopic effect of palladium has been applied in different ways to separate hydrogen isotopes for many years. At Savannah River Site palladium deposited on kieselguhr (Pd/k) is used in a thermal cycling absorption process (TCAP) to purify tritium for over ten years. The need to design columns for different throughputs and the desire to advance the performance of TCAP created the need to evaluate different column designs and packing materials for their separation efficiency. In this work, columns with variations in length, diameter and metal foam presence were tested using an isotope displacement method. A simple computer model was also developed to calculate the number of theoretical separation stages based on the test results. The effects of column diameter, metal foam presence and gas flow rate were identified.