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

Several dyes (quinizarin, indigo, 1,4-diketo-2,5-dimethyl-3,6-diphenylpyrro lo[3,4-c]pyrrole) were loaded within faujasites and mordenite. In the prese nce of organic solvents, leaching was observed. However, after treatment wi th 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 diffus e reflectance UV/VIS spectroscopy, diffuse reflectance infrared spectroscop y, thermogravimetry/differential scanning calorimetry, XRD and nitrogen ads orption, both before and after the SiCl4 treatment. In comparison with the untreated dye loaded zeolite, the thermal stability of the dye inside the s ealed zeolite increased. The treatment does not have any influence on the f ramework composition or the dye.