Capture of CO2 using enzymes, ionic liquids and membrane technology

Details

Supervisors

Luis Alconero, Patricia ; Molina Fernandez, Cristhian

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux, à finalité spécialisée

Abstract

The urgent climate crisis has prompted extensive research on carbon capture technologies. The benchmark technology, chemical absorption using amine-based solvents (such as monoethanolamine), is known for its high energy consumption and significant environmental impact. To address these challenges, this thesis proposes a more environmentally friendly approach by taking advantage of gas-liquid membrane contactors (GLMCs) using biocatalytic membranes and aqueous benign solvents. This study focuses on modifying a polyvinylidene fluoride (PVDF) membrane by incorporating a polydopamine coating, followed by the addition of a polyionic liquid (PIL) layer on the membrane surface. Carbonic anhydrase (CA), an enzyme which has attracted significant attention for its properties as a green cataylyst, is covalently bonded to the superficial PIL layer using glutaraldehyde (GLU). A novel ionic liquid monomer, Vinylaminopropylimidazolium bromide [VApIm][Br], was developed specifically for this application, as its functional groups enable the covalent immobilization of CA. The optimal biocatalytic membrane was determined through activity tests during which different monomer solution compositions and enzyme immobilization protocols were tested. Furthermore, these activity tests showed that by covalently linking CA to the PIL layer, there were no enzymatic activity losses when comparing to physically adsorbed enzymes, which is a very valuable result. The optimal biocatalytic membrane was then evaluated in a lab scale GLMC process setup, demonstrating an average Kov of 7.6e-5 m/s. This means the modi- fied membrane enhanced CO2 absorption by a factor of three compared to pristine PVDF membranes. Moreover, due to the use of covalent bonding, the membrane exhibited stable performance upon reuse, with a retention of 92.6% of its CO2 absorption capacity after 4 cycles.