Effect of aprotic solvent on characteristics of Al2O3 ceramic hollow fiber substrates prepared by phase inversion for hydrogen permeation applications

Abstract

The phase inversion procedure was used to prepare Al2O3 ceramic hollow fiber substrates (AlCHFS) utilizing the dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAC), and 1-methyl-2-pyrrolidone (NMP) aprotic solvents. Different aprotic solvent and non-solvent (water) interactions were used to calibrate different ceramic oxide substrates. AlCHFS with an asymmetrical structure consisting of a finger-like structure on the lumen side and a pore structure on the shell side was obtained using an aprotic solvent/non-solvent pair with a high total Hildebrand solubility (δt). As the aprotic strength was reduced, the finger-like structure on the shell sides became more prominent. Hydrogen permeation studies conducted between 350°C and 450°C reveal that the Pd-coated AlCHFS produced from DMAC aprotic solvent has the maximum hydrogen flux (~0.24 mol m−2 s−1). The activation energy for the thermally activated hydrogen transport process through the Pd-coated AlCHFSs is determined to be around 11.06–14.61 kJ mol−1 in the temperature range of 350°C to 450°C, and it increases linearly with increasing surface porosity of ceramic oxide substrate.

Keywords

• phase-inversion process
• aprotic solvent
• Al2O3
• alumina hollow fiber support
• microstructure