Carbon dioxide is one of the most abundant gases in our universe. We are creating tons of it on our planet, there are dry ice caps on Mars and even Venus has a carbon rich layer. But for all its abundance, it is still not very well understood by the general public. It isn’t even fully utilized in industrial applications.
For example, many in the business community would have no idea that CO2 can be put into a liquid state and that this liquid can be a very eco-friendly and efficient way to get rid of contaminants.
While most of us know that carbon dioxide behaves like a gas at normal temperature and pressure, and some of us may understand that if we freeze the gas it forms dry ice, not many know that if we apply the right temperature and pressure we can change the gas into liquid form.
How does LCO2 Extraction work?
This liquid form of CO2 is known as LCO2 or supercritical carbon dioxide and is excellent for use in a variety of extraction processes. The biggest advantages of using LCO2 are the low levels of toxicity and its minimal environmental impact, so liquid CO2 is rightly considered a greener alternative over many traditional methods of extraction.
There are also a number of other advantages to using CO2 in this state. A wide variety of compounds can be effectively extracted with very minimal damage or denaturing since LCO2 is extremely stable and the temperature required for the process is relatively low. Contaminants are miscible in liquid CO2 making it effective for selective extraction.
But Is It Really Green?
Most people do (correctly) associate carbon dioxide with global climate change, as it is a greenhouse gas that must be controlled to slow down climate change, hence the need to reduce carbon emissions. So why does liquid CO2 count as a green alternative?
Well, the eco-friendliness of liquid CO2 is based on the source of the carbon dioxide. All the gas used in these processes is in fact by-products of other industrial processes. In other words, the carbon dioxide used to make supercritical CO2 has already been used before in some other process and is being recycled instead of released into the atmosphere.
By reusing this CO2 and recycling it for a variety extraction and cleaning purposes there is no increase in the net CO2 we produce as a species. This is why the process is considered a green alternative to traditional methods of extraction.
There are now a number of things that liquid carbon dioxide is used for. Essential oils are created with the extraction process. Hydrocarbons and Perchloroethylene (PERC) can be replaced with liquid carbon dioxide in the dry cleaning process to make it much less harmful to the environment. Even caffeine can be extracted using this state of CO2. In the herbal supplement industry the liquid is used to rid plants of metals and pesticides without causing damage to the nutrients.
Liquid CO2 can thus be used for everything that requires efficient extraction, from removing dirt from garments to extracting contaminants from silicone tubing and implants.