Kbphillipsite was prepared using a hydrothermal method. Soluble glass and sodium aluminate were used as raw materials in the absence of an organic template. Investigations regarding the K＋ ions were con- ducted at room temperature to determine the ion-exchange capacity in the seawater sample and the selectivity coefficient of the mixed K＋-Na~ solution. The sample was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersion spectroscopy （EDS）. The K＋ ion- exchange capacity is 51 mg/g in seawater and the selectivity coefficient is 75.1 in the mixed K＋-Na＋ solution. The sample has a selectivity preference for K＋, and therefore can be used to selectively extract potassium from seawater. The sample composed of Si, Al, K, Na, and O exhibits a cross-like shape and is a typical K-phillipsite structure.
