Polymer Layer-Accelerated CO<sub>2</sub> Absorption in Aqueous Amino Acid Solutions
Zewen Zhu, Nitesh Kumar, Uvinduni I. Premadasa, Joshua T. Damron, Diāna Stamberga, Nicholas Oldham, Ying‐Zhong Ma, Radu Custelcean, Vyacheslav S. Bryantsev, Benjamin Doughty, Santanu Roy, Vera Bocharova
Abstract
Direct air capture (DAC) of CO 2 via solvent-based absorption is considered a promising negative-emission technology. However, the low concentration of CO 2 in the air and slow transport into the solvent make DAC notoriously challenging to implement without costly investments. In this study, we explore the fundamental role that the bulk and surface properties of CO 2 -permeable polymer membranes play in enhancing the efficiency of the solution sorption process in passive DAC of CO 2 . This work leverages various spectroscopic and computational studies to demonstrate that a hybrid system, comprising a reusable CO 2 -permeable polymer layer placed atop an aqueous amino acid (AA) solution, can outperform a pure aqueous AA system by 2-fold. We show how the enhanced solubility of CO 2 in the polymer layer can improve the transport of CO 2 into the aqueous phase, while the chemistry of the polymer can control the interfacial barrier for CO 2 permeation and the interfacial concentration of reactive AAs. The derived knowledge of the material properties achieved here can aid in the design of DAC systems with improved performance.