Development of melamine-based covalent organic framework-MOF pearl-like heterostructure integrated poly(ether-block-amide) for CO2/CH4 separation. Issue 2 (April 2023)

• Record Type: Journal Article
• Authors: Ghanbari, Roham; Marandi, Alireza; Zare, Ehsan Nazarzadeh
• Is Part Of: Journal of environmental chemical engineering. Volume 11:Issue 2(2023)
• Publication Date: 2023-04
• Subjects: Covalent-organic framework -- Metal-organic framework -- Membrane -- Gas separation -- CO2; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2023.109269
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Regarding gas separation application, covalent organic frameworks (COFs) are one of the supreme ones because of their numerous merits, such as ordered pores, excellent compatibility with organic particles, and a diverse range of functionality. Unfortunately, the pore size of these nanomaterials is wider than most gas sizes, so there is an explicit limitation to using them in the gas separation field. Herein, the confined growth of metal-organic frameworks (MOFs) in a facile way in melamine-based COF pores (mCOFs) was proposed. There is some one-dimensional channel in two-dimensional COFs; therefore, there is a perfect possibility for confined growth of MOF in those channels with pearl-like structures. After forming these COF-MOF nanohybrid particles (CXMs), a polyether block amide (Pebax) membrane with excellent size sieving and high molecular transport was fabricated. The permeability and selectivity rates of neat Pebax, mCOF/Pebax, and CXM/Pebax membranes were compared systematically. It was found CXM/Pebax membrane had much better CO2 /CH4 selectivity, and long-term stability was enhanced simultaneously. The CO2 /CH4 selectivity reached 44.2 ± 1.3 for the optimized membrane elucidating 2.3 folds improvement compared to the neat membrane and surpassing Robeson's upper bounds. The long-term tests elucidated that the optimized membrane kept 94% of its initial CO2 /CH4 selectivity, 25% higher than the unmodified one. Graphical Abstract: ga1 Highlights: Melamine-based covalent organic framework-MOF pearl-like heterostructure synthesized. MOF particles grew inside one-dimensional pores of covalent organic frameworks. Newly synthesized pearl-like heterostructures incorporated into the Pebax membrane. Optimized membrane surpassed Robeson's upper bounds due to high CO2 /CH4 selectivity. Optimized membrane needed 1.2% of its mass ratio from heterostructure.