Synthetic gmelinite zeolites are prepared via (i) hydrothermal conversion of strontium-containing zeolite Y and (ii) the use of a DABCO (1,4-diazabicyclo [2,2,2] octane) polymer structure-directing agent. The synthetic materials are compared to a sample of natural gmelinite. The adsorption capacities of the three gmelinites after ion exchange with Na+, Sr2+ and La3+ for adsorbates such as water, methanol, ethanol, propanol, nitrogen, n-hexane and cyclohexane are presented. It is shown on each type of gmelinite and independent of the degree of faulting, the adsorption capacities of nitrogen, propanol, n-hexane and cyclohexane increase when monovalent cations are replaced by multivalent cations. However, adsorbates such as water, methanol and ethanol do not show significant variations in adsorption capacity with exchangeable ion valency. (C) 2000 Elsevier Science B.V. All rights reserved. tic gmelinite zeolites are prepared via (i) hydrothermal conversion of strontium-containing zeolite Y and (ii) the use of a DABCO (1,4-diazabicyclo [2,2,2] octane) polymer structure-directing agent. The synthetic materials are compared to a sample of natural gmelinite. The adsorption capacities of the three gmelinites after ion exchange with Na+, Sr2+ and La3+ for adsorbates such as water, methanol, ethanol, propanol, nitrogen, n-hexane and cyclohexane are presented. It is shown on each type of gmelinite and independent of the degree of faulting, the adsorption capacities of nitrogen, propanol, n-hexane and cyclohexane increase when monovalent cations are replaced by multivalent cations. However, adsorbates such as water, methanol and ethanol do not show significant variations in adsorption capacity with exchangeable ion valency.