The UK Government has set targets for the reduction of CO2 emissions of 80 % by 2050. Post-combustion capture of CO2 from power plants is key if we are to achieve these targets. Post-combustion CO2 capture is challenging due to the low concentration of CO2 in the waste stream and the presence of impurities (H2O, NOx, SOx, etc). Post-combustion capture adds energetic cost via the requirement to capture and compress the CO2. Amine-based scrubbing processes are being evaluated for post-combustion CO2 capture. This is a costly process, and the amines are corrosive. Other candidate technologies include physical adsorption into solid sorbents coupled with pressure-swing or temperature-swing adsorption/desorption. In principle this may lower the energy overhead, but the volume of sorbent required is extremely large, limiting the range of sensible materials. Membrane-based processes have potential advantages over the above. In particular, there are no losses due to heat required to regenerate and release CO2 from the spent sorbent or solvent, and the footprint for the technology and amount of material required is comparatively small.
Here, we will develop advanced mixed matrix membranes (MMMs) technology utilising organic fillers, rather than inorganic fillers, that could be cost-effectively fitted to power plants to separate and capture CO2. There has been much research on inorganic-organic MMMs, using fillers such as zeolites and MOFs. However, it is challenging to achieve a homogeneous dispersion of the inorganic filler particles in the polymer matrix. This is exacerbated by the lack of compatibility between most fillers, which are frequently crystalline inorganic or metal-organic materials, and the membrane polymers, which are invariably amorphous and organic. We build therefore on our unique report of organic-organic MMM (Angew Chem Int Ed, 2013) , where excellent dispersion of the organic filler was found and there was good adhesion between the organic polymer and the organic filler, both of which are predominantly aromatic structures. We address this by bringing together two UK groups who have pioneered in the development of novel porous membranes (Budd) and new microporous organic materials (Adams, Cooper).