Reinforced SIL-1 micromembranes integrated on chip: Application to CO2 separation

• On chip SIL-1 micromembranes on customized Si3Nx microsieves.
• Nominal permeable areas as high as 19.9% of the total chip area.
• Enhanced CO2 separation performance on corrugated SIL-1/Si3Nx micromembranes.
• Increased CO2 sorption affinity for SIL-1/Si3Nx micromembranes.

A novel 4-step microfabrication process is proposed in this work to prepare arrays of c-oriented silicalite (SIL-1) micromembranes on customized silicon nitride (Si3Nx) microsieves. The arrays are integrated on chip and their overall porosity values can be tuned from 1.6% to 19.9%. A low stress Si3Nx microfabricated sieve has been used as support to reinforce via mechanical interlocking and to reduce the effects of the residual stress during membrane processing. The secondary hydrothermal growth over the Si3Nx microsieves also changes the SIL-1 chemistry, improving its affinity towards CO2 adsorption. As a result, the SIL-1/Si3Nx micromembranes integrated on chip facilitate the preferential permeation of CO2 in CO2/H2 mixtures, showing a maximum CO2/H2 separation factor of 16.9 and a CO2 permeance of 8.2×10−7 mol m−2 s−1 Pa−1 at ambient conditions.

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