Adsorbent-containing kapok fiber membranes with high burning rates were developed to remove radionuclides and toxicants from liquid wastes and reduce the total waste volume. The zeolite-fiber membranes were made from natural kapok fibers without allowing the formation of physical or chemical bonds with the zeolite powder. The desorption rate of the adsorbent powder was measured to be within 5% in the aqueous solution for four types of adsorbents with various micro sizes. The adsorption rate of non-radioactive cesium ions with and without the fiber membrane was measured to confirm the effect of the fiber membrane on the adsorption capacity of the adsorbent. Finally, the adsorbent-containing membranes were burned with a volume reduction of 82 wt% without volatilizing the adsorbed cesium at 300 °C.