CO2 capture

University of Melbourne PhD student Julianna Franco has developed a cost-effective CO2 capture system based on the use of inexpensive plastic.

In her membrane gas absorption (MGA) system, the porous plastic acts as a semi permeable barrier, allowing CO2 gas on one side to come into contact with an aqueous solvent on the other, without the gas or liquid dispersing into each other.

MGAs are commonly used to remove gases from, or dissolve them into, water. For an MGA to be effective, however, the membrane must be water-repellent on one side to prevent the water from passing through the pores into the gaseous side of the membrane.

According to Franco’s supervisor, Professor Geoff Stevens, past research on the use of polypropylene as a membrane for CO2 capture concluded that it was unsuitable for MGA use. The plastic’s pores were observed to ‘wet’ in the presence of the aqueous solvent used to absorb CO2
from the gaseous phase, allowing the two phases to mix.