surfactant or cesium solutions were prepared (0.5–15 mM). The zeolite was added to the solutions at a concentration of 10 g/L. The suspensions were agitated for 24 h using a shaker; the precipi- tates were separated by centrifugation (10,000g for 20 min) and freeze-dried. The percentage of carbon in the precipitates, indicat- ing the amount of organic cation or polymer adsorbed, was mea- sured using a CHNSO analyzer (Fisons, EA 1108, Waltham, MA, USA).