Spectral properties of proflavin in zeolite-L and zeolite-Y

The absorption and emission spectral properties of proflavin (3,6-diaminoacridine (PF)) exchanged zeolite-L and zeolite-Y at different loading levels have been investigated. The emission intensity of PF was decreased on increasing the concentration of dye in both the zeolites due to self-quenching. In zeolite-L, PF molecules predominantly exist as monoprotonated species (PFH+) with some diprotonated species (PFH22+) and shows higher emission intensity whereas in zeolite-Y PF molecules mainly exist as monoprotonated species (PFH+). The lifetime measurements of PF in both the zeolites showed biexponential decay with a short- and long-lived species.