Nickel aluminate spinel reinforced ceramic hollow fibre membrane

• Improved flexural strength of alumina hollow fibre membrane by forming NiAl2O4.
• Porosity of NiAl2O4 reinforced alumina hollow fibre membrane was kept above 46%.
• Effective pore size of hollow fibre membrane was estimated to be 211–269 nm.
• Formation of NiAl2O4 is cost effective for reinforcement of hollow fibre membrane.

Ceramic hollow fibre membranes are suitable for application in many industrial processes that involve harsh conditions such as high temperatures and concentrated organic solvents because of their high thermal and chemical stability. The major limitation of ceramic hollow fibre membrane is the brittle nature of ceramic materials, which leads to difficulty in large scale production and failure in pressurised processes. This paper presents the reinforcement of alumina (Al2O3) hollow fibre membrane by nickel aluminate spinel (NiAl2O4). The ceramic hollow fibre membrane was fabricated by the widely used phase inversion method. The NiAl2O4 phase was formed by the reaction of nickel (II) oxide (NiO) with Al2O3 during sintering. A maximum flexural strength of 156 MPa was achieved by the NiAl2O4/Al2O3 hollow fibre membrane containing 16.4 wt% of NiAl2O4, which was 2.3 times of that of the pure alumina sample. The 16.4 wt% NiAl2O4/Al2O3 hollow fibre membrane had a porosity of 46.8%, a mean pore size of 330 nm determined by a gas bubble pressure method, and a pure water flux of 597 L/m2 h bar at a testing pressure of 2 bar. NiAl2O4/Al2O3 hollow fibre membrane could achieve a flexural strength comparable to higher-cost yittria stabilized zirconia and silicon nitride hollow fibres within the porosity range of 46.8–55.2%.