Synthesis of Faujasite Films on Carbon Fibers and Characterization of Their Sorption Properties

The ultimate goal of this study is the preparation of materials that prevent organic contamination of satellites in low earth orbit. Carbon fibers were chosen as a substrate because of their light weight and high mechanical resistance, along with a highly accessible surface that could optimize the sorption of the contaminants. Further, the active phase (FAU-type zeolite) was synthesized onto support applying the secondary growth method. The zeolite coatings were crystallized under different conditions in order to control the characteristics of the material. Alkalinity of the initial gel, Si/Al ratio, and synthesis time appear to strongly influence the film characteristics. Thus, highly crystalline FAU-type films with different thicknesses and levels of hydrophilicity were grown. The sorption properties of zeolite films and counterpart powders were investigated by thermogravimetric analyses toward several organic adsorbents (cyclohexane, n-hexane, p-xylene, trimethylbenzene, tetramethoxysilane). The obtained data revealed that the adsorbed quantity of organic species increased with the Si/Al ratio of the zeolite framework due to its increased hydrophobocity. Sorption capacities of the films appeared to be slightly lower than those of their powder counterparts, which was attributed to lower crystal accessibility on zeolite layers. Nevertheless, the set of experimental data demonstrated that the obtained materials are fully conversant with the target application.