Novel Catalytic Membranes for CO2 Removal and Recovery

Catalytic membrane systems offer the possibility of highly selective removal of CO2 from a mixed feed gas (e.g., from a fossil fuel power station or hydrogen production plant) into an aqueous phase, and recovery of pure CO2 from the aqueous phase, for subsequent storage or re-use. We propose to explore the potential of composite membranes composed of a polymer of intrinsic microporosity (PIM) as matrix or sub-layer, together with a synthetic catalyst which acts as a carbonic anhydrase mimic (catalysing either CO2 hydration or bicarbonate dehydration depending on pH). In addition to seeking to heterogenize a known carbonic anhydrase mimic (a Zn(II) cyclen complex), we shall investigate the potential of two novel heterogeneous catalyst systems which have not previously been studied for this type of application: nanoporous Zn pthalocyanine polymer networks and Zn phthalocyanine cubic crystals. We shall also explore possibilities for optimizing a membrane for either CO2 removal or CO2 recovery, through control of local pH within the membrane or through use of catalysts with different pKa values, and hence to develop a unique and highly efficient double membrane system.