In this work, we investigated simulated moving bed (SMB) chromatography designs for purifying lanthanides (Ln) and actinides (An). SMB is a technique where chromatographic columns are arranged in a semi-closed-loop manner to separate feed into two product streams efficiently with minimal use of the eluent. Using neodymium (Nd) and samarium (Sm) as representative Ln elements and surrogates for minor actinides such as americium (Am) and curium (Cm), we investigated SMB designs with the Reillex HPQ.im resin. Using a chromatographic column packed with the resin, model parameters for the SMB design were obtained from the UV-VIS responses of pulse injections of the pure components. The mobile phase used was 0.5-3.0 M nitric acid. A mathematical model based optimization was used to theoretically predict the optimal purification rates for an equimolar mixture of the two components resulting in product purities of up to 99.5%. (C) 2014 Elsevier B.V. All rights reserved.