Enhanced Gas Adsorption in HKUST-1@Chitosan Aerogels, Cryogels, and Xerogels: An Evaluation Study

Abstract

This study investigates the use of chitosan hydrogel microspheres as a template for growing an extended network of MOF-type HKUST-1. Different drying methods (supercritical CO₂, freeze-drying, and vacuum drying) were used to generate three-dimensional polysaccharide nanofibrils embedding MOF nanoclusters. The resulting HKUST-1@Chitosan beads exhibit uniform and stable loadings of HKUST-1 and were used for the adsorption of CO₂, CH₄, Xe, and Kr. The maximum adsorption capacity of CO₂ was found to be 1.98 mmol·g^-1 at 298 K and 1 bar, which is significantly higher than those of most MOF-based composite materials. Based on Henry's constants, thus-prepared HKUST-1@CS beads also exhibit fair selectivity for CO₂ over CH₄ and Xe over Kr, making them promising candidates for capture and separation applications.

Keywords: chitosan beads; drying processes; gas adsorption; metal−organic framework; shaping.