High pressure intrusion–extrusion of electrolyte solutions in aluminosilicate FAU and *BEA-type zeolites

Abstract

The energetic performances of several FAU- and *BEA-type zeolites with different Si/Al molar ratios have been studied by high pressure intrusion–extrusion of water and LiCl aqueous solutions. It has been shown that FAU-type zeolites characterized by a low Si/Al molar ratio (up to 40) demonstrate hydrophilic properties and spontaneous intrusion of water and LiCl solutions. While dealuminated Y zeolite (DaY) with a Si/Al ratio of 110 displayed a shock-absorber behavior under intrusion of LiCl solutions with concentration ranging from 5 to 20 M; however the intrusion of water was spontaneous. The increase of the LiCl concentration leads to an increase of both the intrusion pressure and the intruded volume, but also a better efficiency of the shock-absorber. *BEA-type zeolite with a Si/Al ratio of 90 displayed a spring behavior under intrusion of 20 M LiCl solution with an intrusion pressure of 59 MPa and an intruded volume of 0.09 mL/g, whereas the intrusion of solutions with lower concentration was spontaneous. It has been shown that only zeolites with high Si/Al ratios can demonstrate high pressure intrusion of electrolyte solutions and that the presence of small traces of aluminum atoms changes considerably the behavior of the “zeolite–liquid” system. The characterization of the samples, before and after intrusion–extrusion experiments, by various physicochemical and structural methods has been performed.