Abstract
Covalent organic frameworks (COFs) have a distinguished surface as they are mostly made by boron, carbon, nitrogen and oxygen. Many applications of COFs rely on polarity, size, charge, stability and hydrophobicity/hydrophilicity of their surface. In this study, two frequently used COFs sheets, COF-1 and covalent triazine-based frameworks (CTF-1), are studied. In addition, a theoretical porous graphene (TPG) was included for comparison purposes. The three solid sheets were investigated for aromaticity and stability using quantum mechanics calculations and their ability for water and ethanol adsorption using molecular dynamics simulations. COF-1 demonstrated the poorest aromatic character due to the highest energy delocalization interaction between B–O bonding orbital of sigma type and unfilled valence-shell nonbonding of boron. CTF-1 was identified as the least kinetically stable and the most chemically reactive. Both COF-1 and CTF-1 showed good surface properties for selective adsorption of water via hydrogen bonding and electrostatic interactions. Among the three sheets, TPG’s surface was mostly affected by aromatic currents and localized π electrons on the phenyl rings which in turn made it the best platform for selective adsorption of ethanol via van der Waals interactions. These results can serve as guidelines for future studies on solvent adsorption for COFs materials.
Highlights
Covalent organic frameworks (COFs) are well-known as two-dimensional (2D) and three-dimensional (3D) light porous crystalline [1,2,3]
The dual-linked phenyl group is denoted by ring (A), whereas the three-side linked boroxine (COF-1), triazine (CTF-1) and phenyl (TPG) groups are denoted by ring (B)
This is referred to initial availability of ring A in reactant structures for synthesis of COF-1 and CTF-1, while ring B is built as the secondary part [40]
Summary
Covalent organic frameworks (COFs) are well-known as two-dimensional (2D) and three-dimensional (3D) light porous crystalline [1,2,3]. 195 v/v (total volume per unit volume) at 30 bar and 298 K for methane storage which was higher than the U.S Department of Energy target (180 v/v at 298 K and 35 bar) [5]. COFs have been studied as potential candidate for membrane separation in terms of its pore size, charge, stability, and hydrophobicity of the surface [6]. Consideration of these criteria is important in order to design relevant applications such as aqueous and solvent-based separation and adsorption
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
