Results in Engineering (Dec 2024)
Mixed matrix membranes (MMMs) fabricated via ultrathin Cu-MOF nanosheets for CO2/N2 separation: Low loading but high performance
Abstract
Emerging two-dimensional metal-organic frameworks (MOFs) were widely utilized in the fabrication of mixed matrix membranes (MMMs) for CO2/N2 separation, owing to their high specific surface area, high aspect ratio, layered structure, and nanoscale thickness. In the current work, a novel Cu-MOF nanosheet with an approximate thickness of ∼20 nm has been synthesized for the first time and used as nanofillers to fabricate MMMs with Pebax 2533. In the MMMs, these Cu-MOF nanosheets could self-assemble into a unique stacked configuration within the Pebax matrix, facilitating rapid CO2 transport while extending the transport path for N2, thereby enhancing both CO2 permeability and CO2/N2 selectivity of the obtained Pebax-Cu-MOF MMMs. Furthermore, the high aspect ratio of the Cu-MOF nanosheets promotes good interaction with Pebax, thereby improving interfacial compatibility. Under conditions of 2 bar and 35 °C, the CO2 permeability and CO2/N2 selectivity of the Pebax-Cu-MOF 0.2 wt.% MMM was 619.1 Barrer and 23.89, respectively, representing increases of 231.6 % and 112.4 % compared to pure Pebax. The MMMs also demonstrated excellent long-term stability. These novel Cu-MOF nanosheets exhibit significant potential for applications across a wide range of fields.