Graphene and Graphene Oxide are usually impermeable to gases. However by introducing anomalies in its structure, it can be changed into an effective filter of Green House Gases.
Two groups who are working independently on building a Graphene based membranes which will be able to spate gas molecules as per their molecule size. One of the membranes created separates Hydrogen from a mixture of Carbon Dioxide and Nitrogen. Another membrane which has been created separates the Carbon Dioxide from Nitrogen. Such membranes can find use as a membrane which can be used to capture the Green House gases like Carbon Dioxide which is indicted as the main cause of Global Warming.
Graphene as a filter
Graphene is an atom thick layer of graphite which is finding immense uses in the industry since its discovery in 2004. One of the properties of the Graphene which has excited researchers is its permeability to different gas molecules. Graphene is only one molecule thick and if it can find use as a permeable membrane for gases, it could effect this very quickly.
However Graphene is by itself impermeable to gases. Graphene is difficult to manufacture and inevitably defects creep in like holes, tears, and grain boundaries. More defects can be introduced and it will enable gas to seep through. The defects can be easily created by reacting the Graphene with an acid to form Graphene Oxide. The stiff carbon –carbon bonds are broken and an oxygen atom is introduced in between.
Now coming to the use of the Graphene as a membrane in reducing the green house gases, it has been discovered that if the gases to be separated has a high humidity, the membrane will allow only Carbon dioxide to pass through and stop the Nitrogen from passing through. Researchers believe that the membrane can be used to separate carbon dioxide from different industrial processes, such as coal burning, and thereby reduce greenhouse emissions.