Biochar-based membranes for CO2 separation and capture: from conventional membrane materials to sustainable alternatives

Rapid urbanisation has led to global warming and releasing of CO 2 into the atmosphere which is the primary anthropogenic greenhouse gas, accounting for almost 65% of the radiative forcing that contributes for global warming. With many innovations to mitigate this ongoing climate threat, capturing CO 2 from the atmosphere utilizing membranes-based methods are being focused on in contemporary studies. Membrane separation of CO 2 has higher efficiency, lower energy demand, cost effectiveness and scalability. The present work evaluates the existing membrane-based techniques for CO 2 capture including Polymeric membranes, Inorganic membranes, Mixed Matrix membranes (MMM), Metal organic frameworks (MOFs) based membranes, Nano material infused membrane, Carbon based membranes and biochar-based membranes. Although polymeric membranes have received widespread acceptance for carbon capture (CC), emerging hybrid membranes with multiple carbon capture mechanism, superior mechanical strength and surface chemistry are being extensively studied in recent times. Sustainable and green carbonaceous membranes such as activated carbon and biochar-based membranes formulated from a range of bio-waste is another avenue of recent research that adheres to the circular economy framework. However, there are very few works on biowaste derived biochar membranes for CC, though they show promising efficiency.