Scale-up of zeolite-Y/polyethersulfone substrate for composite membrane fabrication in CO2 separation

A vacuum-assisted deposition setup was developed in pilot scale to scale up and continuously deposit zeolite-Y (ZY) nanoparticles on 14-in wide nanoporous polyethersulfone (PES) substrate. The deposited substrate was used for composite membrane fabrication for carbon capture from flue gas. The effects of operating parameters, including ZY dispersion concentration, pressure differential, and web speed, on the ZY layer thickness and uniformity were studied. A ZY dispersion concentration of 0.08 wt%, a pressure differential of 3.7 in Hg, and a web speed of 3 ft/min were identified as the optimal operating conditions for depositing a thin and uniform ZY layer with a thickness of approximately 160 nm. A mathematical model with two adjustable parameters was derived from Darcy's law to correlate the operating parameters to the ZY layer thickness. After coating a polymeric amine-containing selective layer on the deposited substrate, the formed composite membrane showed a CO2 permeance of 800 GPU with a CO2/N2 selectivity over 150 at the typical flue gas temperature of 57 °C, which was superior to the performance of the membrane coated on the bare PES substrate. This improvement was due to the reduced selective layer penetration and effective diffusional length from the deposited substrate.