Low-cost activated carbon promises scalable water disinfection

Water security has always been high on the list of human sustainable development goals, because we rely on clean water for drinking, washing, and recreational purposes. However, widespread contamination continues to severely threaten the security of water supplies. Among these contaminants, water pathogens are of particularly great concern as they have been directly linked to outbreaks of potentially deadly waterborne diseases such as cholera and diarrhea.

Since most current technologies have serious limitations – for example, chlorination produces halogenated carcinogens and ozonation is costly and dangerous to operate – researchers in the PROTECT center aim to develop scalable, safe, and low-cost water treatment technologies. Recently, researchers used activated carbon, one of the cheapest functional carbons, to perform water disinfections. Activated carbon particles loaded into the cathode of an electrochemical cell transform oxygen molecules into hydrogen peroxide, which is then catalyzed by ferrous ions to form hydroxyl radicals. Based on the strong oxidation potential, hydroxyl radicals play the central role in water disinfection through destroying cell membrane and vital cellular components such as DNA and functional proteins. Results confirmed that E. coli as a model pathogen could be successfully disinfected by the activated carbon-based water disinfection technology (Refer to Catalysts 2019, 9(7), 601 for more details).

Activated carbon is not only cheap but also a sustainable material that could be easily manufactured from biomass precursors such as plants. In addition, the reactor developed by the PROTECT research team could possibly use solar power to generate the electrical energy needed to complete the disinfection reaction. Therefore, this technology is especially attractive for low-income regions.

Written by Long Chen