Capture of CO2 with cation-exchanged boron zeolites

Abstract

The rise of global temperatures necessitates the development and usage of strategies which aid efforts to reach net-zero emissions targets, such as carbon capture. Effective CO2 capture requires adsorbent materials that are affordable, scalable, and efficient in their uptake of CO2. Zeolites, a class of microporous aluminosilicate frameworks, have shown particular promise among sorbents, exhibiting unique structural properties such as uniform pore geometries and local intrapore electrostatic fields, which enable relatively high selectivity and uptake. However, there are some limitations to zeolite functionality, namely worsened performance, selectivity, and uptake/desorption kinetics in humid or low-concentration environments. This project considers boron-containing zeolites in order to address these limitations, hypothesizing that due to weaker electrostatic fields and framework boron incorporation, boron-zeolites may bind adsorbed molecules less tightly, positively affecting hydrophobicity, desorption kinetics, and confinement effects. Structural and performance characterization of synthesized borosilicate zeolites was performed and compared to aluminosilicate zeolites. Analysis revealed improvements to hydrophobicity and desorption kinetics with the incorporation of boron, though Al-materials were superior in terms of absolute uptake capacity.