Stability of dye loaded faujasites against organic solvents: effect of SiCl4 treatment

Abstract

Several dyes (quinizarin, indigo, 1,4-diketo-2,5-dimethyl-3,6-diphenylpyrrolo[3,4-c]pyrrole) were loaded within faujasites and mordenite. In the presence of organic solvents, leaching was observed. However, after treatment with SiCl₄ vapour the pores of the zeolites were sealed and no leaching could be observed. Furthermore, samples of NaY zeolite loaded with 1,4-diketo-2,5-dimethyl-3,6-diphenylpyrrolo[3,4-c]pyrrole were characterised with diffuse reflectance UV/VIS spectroscopy, diffuse reflectance infrared spectroscopy, thermogravimetry/differential scanning calorimetry, XRD and nitrogen adsorption, both before and after the SiCl₄ treatment. In comparison with the untreated dye loaded zeolite, the thermal stability of the dye inside the sealed zeolite increased. The treatment does not have any influence on the framework composition or the dye.