Removal of caffeine by selective adsorption using zeolite adsorbents
AssigneeUnion Carbide Corporation
InventorThomas P. J. Izod
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Abstract
Caffeine is selectively adsorbed from aqueous solutions such as coffee and tea by contact with a particular form of zeolites created by high temperature rigorous steaming of a low sodium form of zeolite Y.
Claims8
Process for removing caffeine from aqueous solutions which comprises contacting in the liquid phase at a temperature of not more than 100.degree. C. an aqueous solution containing at least 0.01 weight percent caffeine dissolved therein with a crystalline zeolitic molecular sieve having a SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of from 4.5 to 35, the essential X-ray powder diffraction pattern of zeolite Y, and ion-exchange capacity of not greater than 0.070, a unit cell dimension, a.sub.o, of from 24.20 to 24.45 Angstroms, a surface area of at least 350 m.sup.2 /g., a sorptive capacity for water at 25.degree. C. and a p/p.sub.o value of 0.10 of less than 5.00 weight percent, and a Residual Butanol Test value of not more than 0.40 weight percent, whereby caffeine is adsorbed on said zeolite, and thereafter isolating the said zeolite from said aqueous solution.
Dependencies are inferred from the claim text.