Design of Enzyme Loaded W/O Emulsions by Direct Membrane Emulsification for CO 2 Capture.

Membrane-based gas separation is a promising unit operation in a low-carbon economy due to its simplicity, ease of operation, reduced energy consumption and portability. A methodology is proposed to immobilise enzymes in stable water-in-oil (W/O) emulsions produced by direct membrane emulsification systems and thereafter impregnated them in the pores of a membrane producing emulsion-based supported liquid membranes. The selected case-study was for biogas (CO 2 and CH 4 ) purification. Upon initial CO 2 sorption studies, corn oil was chosen as a low-cost and non-toxic bulk phase (oil phase). The emulsions were prepared with Nadir ® UP150 P flat-sheet polymeric membranes. The optimised emulsions consisted of 2% Tween 80 ( w / w ) in corn oil as the continuous phase and 0.5 g.L -1 carbonic anhydrase enzyme with 5% PEG 300 ( w / w ) in aqueous solution as the dispersed phase. These emulsions were impregnated onto a porous hydrophobic PVDF membrane to prepare a supported liquid membrane for gas separation. Lastly, gas permeability studies indicated that the permeability of CO 2 increased by ~15% and that of CH 4 decreased by ~60% when compared to the membrane without carbonic anhydrase. Thus, a proof-of-concept for enhancement of CO 2 capture using emulsion-based supported liquid membrane was established.