The synthesis of zeolite beta has been studied using the following templating agents : (i) tetraethylammonium hydroxide (TEA;) (ii) tetraethylammonium bromide-diethanolamine; and (iii) tetraethylammonium hydroxide-tetraethylammonium bromidetriethanolamine. TEA+ ions and TEAOH molecules only have a structure-directing effect. The ratio (Si + Al)/TEA+ in the gel was varied from 2 to 10, the Si/Al ratio from 12 to 10oO. The temperature of crystallization was chosen in the range 368-443 K. The samples were characterized using X-ray diffraction, micrographs, chemical analysis, thermal analysis, IR spectroscopy and nitrogen adsorption. Zeolite beta of good crystallinity (micropore volume = 0.28 cm3 g-') was obtained with Si/Al ratios from 14 to 72. The acid strength and number of acid sites were determined from the calorimetrically measured heat of NH, sorption and from the TPD of NH,. The initial acid strengths of zeolite beta (up to 185 kJ mol-') are higher than those of other high-silica zeolites.Polycrystalline agglomerates are formed instead of small single crystals on the addition of diethanolamine to the synthesis gel. The agglomerates are characterized by a high intercrystalline volume (>0.47 cm3 g-I), which can be influenced in a definite manner by variation of the TEABr/diethanolamine ratio. The presence of triethanolamine initiates the transformation of zeolite beta into a Si02 layer structure at 368 K.
Vicine and convicine as natural occurring toxic compounds in Vicia faba are involved in the formation of hemolytic anemia (favism). Removal of these compounds needs high technological expense. Microbiological degradation with different strains of bacteria was tried. After 3 h incubation with Streptococcus faeciens convicine was converted completely and Vicine to about 95%.
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