Ultra-rapid production of MFI membranes by coupling microwave-assisted synthesis with either ozone or calcination treatment

The objective of this work is to develop an ultra-rapid and reproducible synthesis method for thin and good quality MFI membranes by coupling MW-assisted synthesis with a rapid template removal method. After selecting the experimental conditions (160 °C–2 h–400 W) for obtaining MFI zeolite membranes with (1 0 1) (oblique) preferred orientation by MW-assisted secondary growth, a series of similar membranes were prepared and three methods were compared for the organic template removal: ozone treatment, calcination with a slow heating rate (0.2 °C/min), and calcination with a rapid heating rate (5 °C/min). Supported membranes were characterized with SEM, XRD, TGA and single gas permeation measurements. Membrane thicknesses were highly reproducible (from 1.16 to 1.26 μm). Although their ideal selectivity n/i-C4H10 does not seem to depend on the method used for removing the template (values lies in the range 47–50 between 20 °C and 50 °C), a lower permeance was obtained for the ozone activated membrane, which could result from protruding hydroxyls decorating the pore walls. This work demonstrates that thin MFI membranes can be obtained within less than two days by coupling MW-assisted synthesis with a rapid template removal method, either ozone or thermal treatment with a high-heating rate (5 °C/min).