CHARACTERISATION OF ASYMMETRIC ALUMINA HOLLOW FIBRES: APPLICATION FOR HYDROGEN PERMEATION IN COMPOSITE MEMBRANES

Asymmetric alumina hollow fibres produced by the phase inversion/sintering method present advantages in that high area/volume ratios and low mass transfer resistances are achieved due to the geometric configuration and the pore size distribution, respectively. Here we characterise hollow fibres that were prepared with different internal coagulants and at different sintering temperatures. Additionally, a palladium membrane was deposited on these different hollow fibres and hydrogen permeabilities through them were compared. More fingers were obtained when a mixture of solvent with water was used as internal coagulant, instead of pure water. At the same sintering temperature, nitrogen permeance through the fibre was increased 5-fold when a mixture of solvent and water was used as internal coagulant instead of pure solvent, and the water flux was increased 7-fold. The decrease in the sintering temperature increased the water permeance through the fibre from 21.4 to 63.9 L h-1 m-2 kPa-1, but decreased its mechanical strength from 74 to 41 MPa. The hydrogen permeance at 450 °C was increased from 5.54x10-5 to 3.06 x10-3 mol m-2 s-1 kPa-1 when using a more permeable hollow fibre as substrate. These results elucidate better conditions to fabricate hollow fibres that present low mass transfer resistances.