SYNTHETIC FERRIERITES AS SORBENTS AND MOLECULAR SIEVES

Strontium ferrierite (Sr-D of Barrer and Marshall (1, 2)) has been synthesized and various cationic forms prepared from this zeolite by ion exchange (Li-, Na-, K-, Ca-, and H-forms). Ferrierite, like clinoptilolite (3) and mordenite (4), was found to be stable in acid solution. Measurements were made of the sorption in the ion-exchanged crystals of O2, N2, Ne, Ar, Kr, Xe, CH4, and CO2. In one of the hydrogen forms measurements were also made of the uptake of several aromatic and heterocyclic molecules. Some interesting molecule sieving actions were observed; for example, at -183°C, K-ferrierite sorbed oxygen freely but did not sorb argon. Among all the exchange forms the highest capacity was shown by a H-ferrierite prepared from Sr-D with 0.09N HCl. Experimental isotherms have been analyzed in several instances in terms of the virial isotherm equation K = p Cexp(2A1C + 2 3A2C3+...) corresponding with the osmotic virial equation of the sorbate-zeolite solution. © 1969.