Design of Enzyme Loaded W/O Emulsions by Direct Membrane Emulsification for CO2 Capture

Abstract

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 (CO2 and CH4) purification. Upon initial CO2 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 CO2 increased by ~15% and that of CH4 decreased by ~60% when compared to the membrane without carbonic anhydrase. Thus, a proof-of-concept for enhancement of CO2 capture using emulsion-based supported liquid membrane was established.

Sustainable production of porous chitosan microparticles by energy-efficient membrane emulsification

“…The membrane emulsification methodology was first adapted from the work of Mondal et al [ 7 ] The main parameters involved in this technique were the choice of membranes (track-etch membrane and metallic membrane), composition of dispersed phases and continuous phases, flow rates of dispersed phase and continuous phases, choice of surfactants. The first step to produce the G/W/O double emulsions was to obtain a gas-in-water emulsion, with argon bubbles in a chitosan solution (G/W) ( Fig.…”

“…Membrane emulsification is an energy-efficient emulsification technique where the formation of the droplets is largely dependent on pore size and pore size distribution of the membrane. Also, other factors contributing to the droplet formation: hydrophilicity/hydrophobicity of the active layer of the membrane (layer where the droplet is built), shear stress of the continuous phase on the active layer of the membrane, trans -membrane pressure and interfacial tension between the two phases of the emulsion [ 7 ]. It is a greener process that applies low mechanical stress, consumes less energy and shows reproducibility, while controlling the size of the droplets in a more efficient manner than emulsions formed by traditional methods like ultrasonic waves, high-speed stirring etc.…”

Current and future applications of PVDF-carbon nanomaterials in energy and sensing

“…Recently, Ma et al [17] reviewed physical and chemical methods of improvement of nanofiller dispersion. Among physical (typically less expensive than the chemical ones) methods, the most widely applied are: ultrasonication, milling, and blending.…”

“…SiO2 played a similar role (preventing the GO nanosheets from aggregation) in the PVDF/SiO2/GO tri-layered nanocomposites [19]. Ma et al [17] proposed foaming, using supercritical CO2, to disperse CNFs in PVDF matrix. Among a variety of CNMs, G nanoflakes (and nanosheets [20]) can be applied to improve PVDF mechanical properties and to increase the melting temperature [21].…”

Biocatalytic Membranes for Carbon Capture and Utilization

“…Another promising case involves the formation of a stable emulsion for filling the porous membrane. Mondal et al [107] formulated a water-in-oil emulsion with 1 wt% aqueous disperse phase in corn oil stabilized by 2 wt% Tween 80 and filled the pores of the porous hydrophobic PVDF membrane. The aqueous phase comprised 0.5 g CA per liter potassium carbonate solvent and 5 wt% PEG 300 for enzyme stabilization.…”