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

Abstract

In this work, the potential of utilizing a polyetherimide (PEI) hollow-fiber membrane to separate synthetic biohydrogen mixture (H2/CO2) was studied. From the gas separation experiments, where the effects of feed to permeate pressure ratio (Pfeed/Ppermeate) and stage-cut as key factors were evaluated, it was found that the PEI membrane had the capacity to purify either H2 or CO2. It turned out that different separation settings should be chosen in accordance with the actual technological purpose, defined either as the enrichment of H2 or CO2. The highest H2 concentration (66.4 vol%) in the permeate was achieved at Pfeed/Ppermeate of 4.62 and stage-cut of 0.47, while the peak CO2 concentration (79.2 vol%) in the retentate was obtained by applying Pfeed/Ppermeate of 4.55 and stage-cut of 0.65. The assessment and discussion of results indicated the possible utilization of the CO2-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.