Tunable Gas-Liquid Separation by Surface Charge Modifications: Toward Membrane-Based Carbon Capture and Detection

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Carbon capture is vital for climate mitigation and gas-liquid separation in analytical technologies.
• Nanoporous graphene membranes (NGMs) offer a unique platform for studying gas transport at the atomic level.
• Understanding CO2 transport mechanisms through NGMs at the gas-liquid interface is critical for optimizing these applications.

Purpose of the Study:

• To investigate the CO2 transport mechanism through NGMs at the gas-liquid interface.
• To elucidate the role of pore-edge electrostatics and interfacial hydration in modulating CO2 transport.
• To identify strategies for enhancing CO2 permeance through NGMs.

Main Methods:

• Utilizing all-atom molecular dynamics simulations.
• Analyzing CO2 transport dynamics across various NGMs, including pristine, H-terminated, charged, and functionalized pores.
• Quantifying the effects of pore-edge properties on interfacial water accumulation and CO2 permeance.

Main Results:

• Pore-edge electrostatics strongly influence interfacial hydration, affecting CO2 transport.
• Charged and functionalized pores promote water accumulation, suppressing CO2 transport.
• Hydrophobic pores minimize water blockage, leading to enhanced CO2 permeance.
• Interfacial hydration is identified as a key factor governing CO2 transport at the gas-liquid interface.

Conclusions:

• Contrary to expectations, stronger electrostatic interactions can suppress CO2 transport by increasing interfacial hydration.
• Hydrophobic pore engineering is a promising strategy to enhance CO2 permeance through NGMs.
• These findings have implications for improving carbon capture technologies and carbon-based analytical devices.