This paper investigates the potential of MesoLite ion exchange media for ammonium (NH4+) removal from solution in the presence of competing cations. Batch tests were performed under a range of conditions to assess the effect of contact time, solution pH and solution concentration on the performance and capacity of the media for this application. The data obtained was fitted to the Langmuir and Freundlich isotherm models with the Langmuir model providing the better description of the process. Results indicate a maximum equilibrium capacity of 49 g NH4+-N kg(-1) of media is achievable under the experimental conditions studied. A detailed examination of the data shows that increasing solution concentration and increased contact time provide the best performance at an optimum pH of between 6 and 7. (c) 2007 Elsevier B.V. All rights reserved.