Review on Synthesis and Characterization of Advanced Nanomaterials-based Mixed Matrix Membranes (MMMs) for CO₂ Capture: Progress, Challenges, and Prospects

The rise in carbon dioxide (CO2) emissions is a major driver of global warming, and climate change has intensified the focus on developing effective CO2 capture technologies. Traditional methods, such as absorption, including amine-based systems, adsorption, and cryogenic separation, have been widely studied and implemented. However, many of these approaches face significant economic and environmental challenges, including high energy demands and operational inefficiencies. This highlights the need for more sustainable alternatives. Membrane-based CO2 capture has emerged as a promising solution, offering benefits like reduced costs, compact design, and high operational efficiency. However, the main challenge in membrane development is achieving a defect-free polymer-inorganic interface that enhances separation performance without compromising permeability. The selection of a suitable filler material is crucial for optimizing the gas separation performance of these membranes. This review provides a comprehensive synthesis of the key principles involved in the preparation of mixed matrix membranes (MMMs), with a focus on the latest advancements in synthesis techniques, characterization methods, and surface modifications using cutting-edge polymers and filler materials. Beyond the fundamentals, it offers a critical analysis of the persistent challenges in MMM fabrication, integrating an in-depth techno-economic evaluation and sustainability assessment to position membrane technology in the context of industrial feasibility. The review also incorporates an up-to-date discussion on the technology readiness level (TRL) of membrane-based CO2 capture research, a dimension often overlooked in existing literature. By identifying critical research gaps and outlining forward-looking perspectives, this work sets a foundation for accelerating innovation in the field.