Graphene, a dynamic material made of a one-atom-thick sheet of linked carbon atoms, was previously shown to stop steel from rusting. But soon it will also see use stopping bacteria from corroding metal pipes, according to a study published in the journal ACS Nano.
Graphene can stop bacterial corrosion of metal pipes
Within wastewater-processing facilities like sewage treatment plants, microbes called sulfate-reducing bacteria often colonize the inside surfaces of pipes and other equipment, reports New Atlas. Bacterial colonies take the form of what scientists call "biofilms," and can develop in just 10 days after the pipes have been cleaned — after which they degrade metal pipes into primary ways.
First, the bacterial microbes remove electrons from the surface of the metal while they respire (or breathe). Second, while the bacteria consume organic matter from the water, they produce hydrogen sulfide, a corrosive chemical to metal pipes.
Overcoming limits of bacteria in metal tube coating
While protective polymer coatings may be applied to the interiors of metal pipes, the coatings themselves can become degraded as the bacteria consume their internal plasticizers. Additionally, such protective coatings may become brittle over time, cracking and flaking right off of the pipe surface, after which it enters the water stream.
Because of these limitations, South Dakota School of Mines & Technology research scientist Govind Chilkoor is considering the use of graphene as an alternative primary coating. During lab testing, Chilkoor found that even a single graphene layer — measuring less than 1 nanometer thick — was highly effective at preventing sulfate-reducing bacteria from latching on to the interior surface of metal pipes.
"Graphene can be very antimicrobial," said Chilkoor, reports New Atlas. "It can induce oxidative stress and the bacteria will die."
Since graphene is one of the strongest manmade materials, it's also likely way more durable than the polymers currently employed in protective coatings. As if that weren't enough, graphene is also very thermally-conductive, which means it should perform much better than polymers when used in heat-exchanging pipes.