Biochar, The Filter of the Future
Written by Anna Feerick
Edited by Kelly Chau
March 21, 2022
Edited by Kelly Chau
March 21, 2022
The magic material here to clear your skin, flourish your crops, and keep pollutants out of your drinking water: biochar. For those unfamiliar, biochar is what remains after burning biological matter under low-oxygen conditions and is a cheap, green alternative for filtering out carbon-based pollutants. Many organic pollutants require the use of costly environmental remediation methods (e.g., reverse osmosis and activated carbon), limiting wastewater treatment plants’ options for removal. With strong absorbance and degradation properties, biochar makes an attractive addition to the normal treatment process.
For plants facing trouble with a particular pollutant, additives are combined with biochar to improve its degradation abilities. Adding metals improves the bond-breaking reactions required for degradation. Combining biochar and microorganisms also improves bioremediation, a type of biological degradation. These microbes take free electrons from the biochar, allowing for a quicker and easier breakdown of pollutants. Though the remediation process commonly focuses on drinking water, biochar can also enhance soil microbes, helping crops flourish.
Not only do the absorbance properties of biochar help remove pollutants, but they also attract water molecules, increasing the amount of water available in the soil. As plants access the water held by biochar, the roots burrow through and break the biochar down, turning it into fertilizer. Pollutants already taken up by the biochar can then break down, either through reactions or by the surrounding microbial community.
Prominent classes of molecules that biochar has successfully removed include antibiotics, pesticides, and cancer-causing pollutants such as polycyclic aromatic hydrocarbons. Though biochar is a particularly productive remediation method for these pollutants, it still has the potential to improve. Biochar regeneration (the act of removing the pollutants from the biochar for reuse) is not well studied, especially for new and emerging pollutants. Future research will likely focus on developing biochar capable of removing specific pollutants and look into ways to safely dispose of them once they’re removed.
Image Source: “Biochar pellets” by Lou Gold licensed under CC BY-NC-SA 2.0