Manipulation of Fibril Surfaces in Nanocellulose-Based Facilitated Transport Membranes for Enhanced CO2 Capture
The transition towards sustainable processing entails the use of bio-based alternatives as functional materials to reduce overall carbon footprint. Nanocellulose, due to its natural availability, biodegradability, excellent mechanical properties, tunable surface, and high aspect ratio, is attracting more and more interests as nanoscale additive in polymeric membranes. In this work, an effective way to modify nanocellulose fibril surfaces for performance enhancement in CO2 separation membranes
... aration membranes has been demonstrated. The functionalization promptly triggered intrinsic property responses in favour of nanofiber dispersion and CO2 transport. Thin composite membranes containing the modified nanofibers in water-swelling polyvinyl alcohol (PVA) as well as in the blend of sterically-hindered polyallylamine (SHPAA) and PVA were fabricated and tested using humid gas permeation tests. Defect-free ultrathin (300 nm) hybrid selective layers containing evenly distributed nanofibers were successfully coated. The addition of nanocellulose exhibited enhanced CO2 permeance and CO2/N2 selectivity compared to the neat PVA membranes; CO2 permeance up to 652 GPU with a CO2/N2 selectivity of 41.3 were documented. Functionalization plays a categorical role in the dispersion of nanocellulose fibrils in the SHPAA/PVA blend, increasing the steric stabilization and interface compatibility with the polymer matrix. The tuned interface with PEG groups act as sites for water clusters retention and increased CO2 solubility, thus creating fast diffusion pathways for CO2 transport.