Embedment of Methylene Blue in natural and synthetic phillipsite

Phillipsite was crystallized from a high siliceous aluminosilicate mixture containing Zn cations and methylene blue (MB). The presence of MB did not affect the crystallization, but it resulted in a substantial amount of dye being anchored to the zeolite, despite its narrow channels. Dye-free synthetic phillipsite modified with MB solution showed markedly lower dye content, which, however was considerably higher than those in the MB-treated natural phillipsite and mordenite. The ultra violet/visible (UV-vis) spectra of the dye-modified synthetic phillipsites indicated the presence of MB monomers and oligomers, whereas the spectra of the modified natural zeolites showed protonated MB also. The electron spin resonance spectra of samples crystallized with MB indicated the presence of paramagnetic species.