Enhanced CO₂ Separation Performance of a Modified Composite Membrane Based on a Covalent Organic Framework by...

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Covalent organic frameworks (COFs) are promising materials for gas separation.
• Modifying COFs with ionic liquids (ILs) and deep eutectic solvents (DESs) can enhance their performance.
• Understanding the influence of temperature and humidity is crucial for optimizing COF-based membranes.

Purpose of the Study:

• To investigate the mechanisms of CO2 adsorption and separation in modified COF membranes.
• To evaluate the effects of temperature, humidity, and different solvent modifications (DESs and PEG-ILs) on CO2 separation.
• To provide insights for designing efficient COF composite membranes for industrial CO2 capture.

Main Methods:

• Molecular dynamics simulations were employed to study CO2 adsorption and separation.
• Simulations were conducted under varying temperature and humidity conditions.
• The interactions between COF, solvents (DESs, PEG-ILs), and CO2 molecules were analyzed.

Main Results:

• Higher temperatures increased CO2 permeability in the membranes.
• Optimal humidity levels improved CO2/N2 separation selectivity.
• DES and PEG-IL modifications exhibited distinct effects on membrane structure and gas transport properties.
• Humidity played a dual role, enhancing CO2 transport in DES@COF while causing phase separation and impeding transport in PEGIL@COF at high levels.

Conclusions:

• The study elucidates the role of temperature, humidity, and solvent choice in CO2 separation using modified COF membranes.
• DES and PEG-IL modifications offer different strategies for tuning membrane performance.
• Findings provide valuable guidance for the rational design of advanced COF composite membranes for efficient CO2 capture in industrial settings.