Correlation of Porosity and Permeability in Porous YSZ Microfiltration Membrane for Oil‐in‐Water Separation

ABSTRACT Porous yttria‐stabilized zirconia (YSZ) symmetrical microfiltration (MF) membranes were fabricated via partial sintering of coarse YSZ (d 50 = 2.7 µm) at 1300°C–1500°C. Fine YSZ (fine‐sized YSZ, d 50 = 0.17 µm, 0–20 wt%) was employed as a sintering aid, and PMMA (0–10 wt%) served as a sacrificial template. While increasing fine YSZ content and sintering temperature improved mechanical strength, it concurrently reduced permeance. Conversely, PMMA addition enhanced porosity and permeance, but decreased mechanical integrity and separation efficiency. The optimized YSZ membrane, containing 2.5 wt% PMMA and sintered at 1400°C, exhibited 41% open porosity, 21 MPa flexural strength, and a pure water permeance (PWP) of 437 L m −2 h −1 bar −1 . During the four‐cycle oil‐in‐water (O/W) emulsion filtration, this optimized membrane maintained a stable permeance of 130 L m −2 h −1 bar −1 with 96% separation efficiency. Hermia fouling analysis revealed cake filtration along with standard pore blocking as dominant modes of membrane fouling. Notably, a single air heat treatment at 600°C restored PWP to approximately its initial value.