Feasibility study of polyetherimide membrane for enrichment of carbon dioxide from synthetic biohydrogen mixture and subsequent utilization scenario using microalgae

Summary In this work, the potential of utilizing a polyetherimide (PEI) hollow‐fiber membrane to separate synthetic biohydrogen mixture (H 2 /CO 2 ) was studied. From the gas separation experiments, where the effects of feed to permeate pressure ratio (P feed /P permeate ) and stage‐cut as key factors were evaluated, it was found that the PEI membrane had the capacity to purify either H 2 or CO 2 . It turned out that different separation settings should be chosen in accordance with the actual technological purpose, defined either as the enrichment of H 2 or CO 2 . The highest H 2 concentration (66.4 vol%) in the permeate was achieved at P feed /P permeate of 4.62 and stage‐cut of 0.47, while the peak CO 2 concentration (79.2 vol%) in the retentate was obtained by applying P feed /P permeate of 4.55 and stage‐cut of 0.65. The assessment and discussion of results indicated the possible utilization of the CO 2 ‐rich fraction (produced by the PEI membrane) for the biological sequestration using microalgae. To our knowledge, PEI membranes have not yet been tested in such a concept and thus, the results and experiences can mean a new contribution to the literature.