pH Responsive Carboxymethyl Chitosan/Poly(amidoamine) Molecular Gate Membrane for CO₂/N₂ Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Growing energy demands and environmental concerns necessitate efficient carbon dioxide (CO2) separation technologies.
• Developing advanced materials for gas separation is crucial for mitigating climate change and optimizing energy resources.

Purpose of the Study:

• To investigate the CO2 separation capabilities of a novel blend membrane composed of carboxymethyl chitosan and dendrimer.
• To evaluate the impact of varying operating temperatures and flow ratios on membrane performance.

Main Methods:

• Fabrication of a mixed-matrix membrane incorporating carboxymethyl chitosan and dendrimer.
• Characterization of the membrane's physicochemical properties.
• Testing of mixed gas (CO2/N2) separation performance under varied temperature (60-110 °C) and sweep/feedwater flow ratios (0.33-3).

Main Results:

• A blend membrane with 10 wt.% dendrimer exhibited optimal performance.
• Achieved a CO2 permeance of approximately 100 GPU and CO2/N2 selectivity of around 149.
• Optimal performance was recorded at 90 °C with specific sweep/feedwater flow ratios of 2.33 and 1.67.

Conclusions:

• The carboxymethyl chitosan and dendrimer blend membrane demonstrates significant potential for efficient CO2 separation.
• The observed high performance is attributed to the dendrimer's molecular gate mechanism and the salting out effect of the carboxymethyl chitosan matrix.
• This material offers a promising advancement in carbon capture and separation technologies.