Investigating the Impact of Modified Support on the Performance of Cobalt-Doped Silica Membranes in Hydrogen Separation Processes

Document Type : Research paper

Authors

1 Chemical Engineering Department, Shand University of Technology, Tabriz, Iran

2 Chemical Engineering Department,, Sahand University of Technology, Tabriz, Iran

3 Chemical Engineering Department, Urmia University of Technology, Urmia, Iran

Abstract

In this research, cobalt-doped silica membranes were synthesized using the sol-gel method. The properties of the membrane support are of great importance for selective membrane coating. Membrane support permeability and surface roughness are two important and measurable characteristics in support selection. Therefore, two types of modified supports were selected for this study; the first support with a surface roughness of 160 nm and an average hydrogen permeance of about 5.5 × 10-7 mol m-2 s-1 Pa-1, and the second support with a surface roughness of 54 nm and an average hydrogen permeance of 3.5 × 10-6 mol m-2 s-1 Pa-1 were used. The cobalt-doped silica layer was uniformly coated on both supports, and molecular sieve activity was observed in both membranes permeation. The results show that utilizing a modified support with low surface roughness and high permeance resulted in a cobalt-doped silica membrane with pure hydrogen permeance of 1.3 × 10⁻⁷ mol m-2 s-1 Pa-1 and average ideal selectivity of 40 and 25 for H₂/N₂ and H₂/CO₂, respectively, at 150°C. Conversely, the cobalt-doped silica membrane on the modified support with high surface roughness and low permeability exhibited significantly weaker performance with pure hydrogen permeance of 1.6 × 10-9 mol m-2 s-1 Pa-1 and average ideal selectivity of 16 and 13 for H₂/N₂ and H₂/CO₂, respectively, at the same temperature. The findings demonstrate the appropriateness of the sol-gel process for producing cobalt-doped silica membranes that are selective, but they also emphasize how important it is for the support surface's roughness and permeance to affect the membrane's performance.

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Main Subjects

Journal of Separation Science and Engineering

Articles in Press, Accepted Manuscript
Available Online from 09 July 2024

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