Fluorescence confocal optical microscopy imaging of the grain boundary structure of zeolite MFI membranes made by secondary (seeded) growth

Fluorescence confocal optical microscopy (FCOM) was used to characterize MF I membranes made by secondary (seeded) growth. It is demonstrated that FCOM is a powerful tool for the non-destructive evaluation of zeolite membranes . This technique can provide two-dimensional, optical sections of the membr anes with submicron resolution without physical damage to the sample. When contrasted with fluorescein-Na salt, it is shown that the grain boundary ne twork in MFI membranes can be observed along the thickness of the membranes . Moreover, defects that do not propagate to the membrane surface acid, the refore, are not detected by SEM, can be clearly imaged. One example of such a defect are internal cracks in the membrane. (C) 2001 Elsevier Science B. V. All rights reserved.