CHARACTERIZATION AND CATION-EXCHANGE PROPERTIES OF ZEOLITE SYNTHESIZED FROM FLY ASHES

Zeolite P was formed from class F fly ash under hydrothermal condition s. The fly ash was reacted with 2.8 or 5 M NaOH at 100 degrees C. Zeol ite of the above type was produced regardless of the NaOH concentratio n or the addition of quartz, thus indicating its formation over a wide range of conditions. The zeolite produced was of the NaP-type with a fibrous morphology. Analysis of the pore structure of this zeolite by the BET method indicates a type II isotherm. The specific surface area s of synthesized zeolites increased from 28.5 to 41.1 m(2)/g when the NaOH concentration was increased from 2.8 to 5.0 M. This zeolite showe d a significant selectivity for the uptake of Cs and Sr. Cs uptake ran ged from 7.67 to 8.61 meg/100 g while that of Sr ranged from 9.8 to 10 .54 meg/100 g. The value obtained depended on the specific synthesis c onditions. These values are higher than those observed for tobermorite prepared from the same fly ash even though the tobermorite exhibited a higher specific surface area.