Zeolites X, Y, and Na-P1 (90℃) and analcime and sodalite (150℃) were synthesized from Class F fly ash using 3 M sodium hydroxide solutions and autogenous pressures. The partially zeolitized fly ashes were dried overnight in air at roomtemperature and then characterized using X-ray diffraction and SEM. On occasion, a few samples were dried to constant weight for an additional 8-10 mm in a microwave oven to remove bound water as well. The dried samples were evaluated for their abilityto adsorb sulfur dioxide (SO{sub}2) from a simulated stack gas containing ~2000 ppm SO{sub}2. Determinations were made in real time using a UV/vis spectrophotometer followed by a total sulfur analysis of the "loaded" samples once testing was complete.Breakthrough curves indicate that the zeolites in the samples are able to remove all of the SO{sub}2 in the simulated flue gas (zero SO{sub}2 emission) for varying periods of time, and that the actual amount of SO{sub}2 removed by the zeolite depended onthe type and degree of "dryness" of the zeolite or zeolite-like material present. For example, a 7 day 150℃ cured sample containing analcime and sodalite was able to adsorb 6-7 mg of SO{sub}2 per gram of sample regardless of the source of the fly ash,whereas a 90℃ cured sample containing X, Y, and NaP1 was significantly less efficient.
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