The industrial sector is well known for emitting large amounts of greenhouse gases that contribute to global warming and climate change. However, as the world eagerly seeks solutions to reduce carbon emissions, developments in membrane technologies for carbon capture are proving invaluable.
Why use membrane technology for carbon capture?
Membrane technology is essential for the decarbonization of industrial activity and energy generation, using various barriers to separate and store carbon dioxide (CO2) emissions from other gases such as nitrogen and oxygen.
For example, the chemical manufacturing industry is expected to report 186 million tonnes of CO2 equivalent in 2022, a 6% increase from 2013. Meanwhile, just one tonne of cement produces 0.8-0.9 tonnes of CO2, accounting for 8% of global CO2 emissions.
Modern absorption technologies are energy efficient and easier to scale up for large-scale applications than other methods. Membrane gas separation processes also have 40% to 60% lower environmental impact and do not require harmful chemicals.
New design and configuration
Advances in design and configuration in membrane technology are improving efficiency, selectivity and resilience in carbon capture and storage. For example, hollow fibers absorb 40%-50% of exhaust gases to improve gas and liquid flow.
Similarly, in a pilot study funded by the U.S. Department of Energy, thin-film composite membranes effectively captured 99% of carbon dioxide emitted by cement industry emissions and power plants at 95% purity, which scientists say could be stored underground, used to reinforce concrete, or added to products.
Another component development is hybrid systems that integrate membranes with other carbon capture processes to increase efficiency. These technologies include absorption, adsorption and cryogenic technologies. For example, membrane cryogenic hybrid methods can achieve 86% CO2 capture and 90% purity with low energy input.
Meanwhile, power plants can benefit from smart membranes (sensors and other adaptive mechanisms) that allow them to modify their membrane design in real time to increase operational efficiency.
Development of membrane materials
The membrane materials themselves have also made great strides towards improving CO2 separation and performance. To date, polymer-based membranes have been preferred, but they have some limitations.
The National Energy Technology Laboratory’s Point Source Carbon Capture Program has made great strides in CO2 capture using permeable and semi-permeable materials that are more resistant to thermal and physical changes, more resistant to gaseous pollutants, and more integrated into hybrid systems.
Recent materials advances include:
Polymer nanocomposites: Novel polymer membranes composed of inorganic nanoparticles and an organic polymer matrix, offering improved gas permeability. Metal-organic frameworks: Highly porous materials that effectively separate CO2 and nitrogen. Ceramic membranes: Made from inorganic materials such as zirconia and alumina, they are corrosion- and heat-resistant. Ionic liquid-based membranes: Use liquid salts to form polymers that improve solubility and selectivity for CO2. Biomimetic mineralization: Mimic natural processes such as photosynthesis to capture CO2 and convert it into stable materials.
Challenges for future membrane-based carbon capture
Although progress in membrane technology for carbon capture has been impressive, there is still room for improvement. Researchers need to continue developing membrane materials with high selectivity and permeability, but at present, this remains a major challenge.
Some materials cannot withstand harsh environments: high temperatures, pressures and chemicals, for example, can cause certain membranes to degrade, evaporate or perform poorly.
Membrane fouling is also a major issue: unwanted surface material builds up on the membrane, reducing its ability to capture CO2 effectively. Scientists at MIT may have solved this problem by coating power plant exhaust gases with algae. Seaweed sequesteres 50% of the planet's CO2 and contains proteins and minerals that can absorb other gases involved in carbon capture.
Advances in membrane technology catalyze future carbon capture
Developments in membrane technology are revolutionizing carbon capture across the industrial and energy sectors. From modern configurations to new membrane materials, advances are demonstrating viable solutions for mitigating greenhouse gas emissions.
