Advances in Halloysite Nanotubes (HNTs)-Based Mixed-Matrix Membranes for CO2 Capture

Membrane technology promises a highly economical and efficient solution for CO2 separation. Many polymeric membranes have been reported in the past for the separation of gases specially to remove CO2 from natural gas and low-pressure flue-gas streams. The performance of membranes can be tailored by dispersing nanofillers in a polymeric matrix to produce mixed-matrix membranes (MMMs). This not only adds mechanical strength to membranes but also reduces compaction of the polymeric layer at high pressure and maintains high performance. Halloysite nanotubes (HNTs) gained attention in gas separation technology and due to their tubular structure have been used in a variety of applications in biomedical, coating, composite, and electronic industries. However, very little but conclusive literature and reviews are available to indicate that functionalized and non-functionalized HNTs can improve the performance of MMMs for efficient CO2 capture. The current status and gaps for potential applications of HNTs-based membranes for gas separation are identified and reviewed.