Preparation of a Porous, Sintered and Reaction-Bonded Si3N4 (SRBSN) Planar Membrane for Filtration of an Oil-in-Water Emulsion with High Flux Performance.

A porous, sintered, and reaction-bonded Si3N4 (SRBSN) planar membrane was prepared by phase-inversion tape-casting, nitridation (at 1350 °C), and sintering (at 1650 °C) of silicon slurry. The membrane was comprised of uniform rod-like β-Si3N4 crystals with a large length/diameter ratio and had high porosity and bending strength. The prepared membrane features a typical asymmetric structure with a skin layer, a sponge layer, and finger-like voids and an average pore size of 0.61 μm. A high permeation flux of 367 L m−2 h−1 and an oil rejection of 88.6% were recorded in oil-in-water emulsion separation experiments. These results suggest that SRBSN membranes have excellent potential for the treatment of oily wastewater.