β-silicon nitride membrane with robust inorganic-organic hybrid hydrophobic surface for water-in-oil emulsion separation

Abstract

Robust hydrophobic membranes are promising for effective separation of water-in-oil emulsion, which is becoming extremely critical challenge in many sectors, including oil refinery and petrochemical industries. In this paper, robust hydrophobic ceramic membrane was fabricated and successfully applied for the water-in-oil emulsion separation process. First, porous β-silicon nitride (Si3N4) membranes with unique rod-like grains and three-dimensional network structure were fabricated. The preparation procedure was optimized considering the morphological properties, porosity, permeability and mechanical characteristics. Then, the optimized membrane was converted to a hydrophobic structure with water contact angle of 136.1°. The hydrophobic modification was achieved using organosilane pyrolysis coating method, which resulted in the formation of a robust inorganic-organic hybrid hydrophobic coating layer on the membrane structure. The hydrophobic membrane was employed for the separation of water-in-oil emulsion. At a feed pressure of 1 bar, a permeate flow of 80 L/m2 h with a water rejection of 94.3% was obtained. The presented hydrophobic silicon nitride membrane in this study is promising for a range of water-in-oil emulsion separation applications, particularly in harsh conditions.