By: Dr. Franyi Sarmiento, Ph.D., Inspenet, April 5, 2022
A team of Norwegian-American technologists has developed a polymeric membrane that improves the efficiency of carbon dioxide separation in mixed gas emissions, with the presence of steam, as occurs particularly in power plants.
If a multilayer membrane is used in an integrated manner with existing filters, the selectivity of the CO₂ filtrate can be increased in some cases by more than 150 times, the authors assessed in an article published last week in the journal Science.
A persistent challenge for this class of membranes has been finding a balance between permeability and selectivity, explains a statement issued April 1 by North Carolina State University, whose researchers were involved in the development.
The higher the permeability, the faster the gas can flow through the membrane, but as the permeability increases, the selectivity decreases, which means that nitrogen or other components also pass quickly through the membrane. This humid environment creates the conditions for the invention to work and to reduce the proportion of CO₂ with respect to other gases in the mixture.
The research team grew chemically active polymer chains that are both hydrophilic and CO₂-philic on the surface of existing membranes. This increases the selectivity of CO₂ and causes a relatively small reduction in permeability.
To demonstrate the ability of the new membranes, the team tested them with mixtures of CO₂ and nitrogen, a characteristic combination in power plant emissions, according to study co-author and chemical engineer Richard Spontak. This demonstrated that the new product can “greatly improve the selectivity of membranes for CO₂ removal while maintaining a relatively high CO₂ permeability.”
Also, the membrane was tested in a mixture of carbon dioxide and methane, “which is important for the natural gas industry,” according to Spontak. Other possible applications he cited are biomedical and the “scrubbing of CO₂ from the air in a submarine.”
The filters that will include this new invention will not take up much physical space, can be manufactured in a wide variety of sizes, and can be easily replaced, the researchers say.
An alternative that is currently in use is the chemical absorption of carbon dioxide, which consists of bubbling mixed gases through a column containing some compound from the group of amines in liquid form, where the CO₂ is removed. However, absorption technologies leave a significantly higher carbon footprint at the outlet, while liquid amines are often toxic and corrosive.
Another challenge faced by filters against the best-known greenhouse gas has been cost, the University of North Carolina points out. The more effective previous membrane technologies were, the more expensive they tended to be, but the development of this new technology from membranes, which is already in widespread use, makes it “commercially viable”. According to the authors, the redesigned surface of these membranes increases the cost, but without ceasing to be profitable.
Source Actualidad RT in Spanish : https://actualidad.rt.com/actualidad/425948-membrana-borrar-huella-carbono-emisiones
Loading...
