Srikanth Singamaneni, professor of mechanical engineering & materials science, and Young-Shin Jun, professor of energy, environmental & chemical engineering, and their teams blended their expertise to develop an ultrafiltration membrane using graphene oxide and bacterial nanocellulose that they found to be highly efficient, long-lasting and environmentally friendly.
If their technique were to be scaled up to a large size, it could benefit many developing countries where clean water is scarce.
Biofouling accounts for nearly half of all membrane fouling and is highly challenging to eradicate completely.
The team then incorporated graphene oxide (GO) flakes into the bacterial nanocellulose while it was growing, essentially trapping GO in the membrane to make it stable and durable.
After GO is incorporated, the membrane is treated with base solution to kill Gluconacetobacter.
“If you want to purify water with microorganisms in it, the reduced graphene oxide in the membrane can absorb the sunlight, heat the membrane and kill the bacteria,” Singamaneni said.
Singamaneni and Jun and their team exposed the membrane to E. coli bacteria, then shone light on the membrane’s surface.
While the bacteria are killed, the researchers had a pristine membrane with a high quality of nanocellulose fibers that was able to filter water twice as fast as commercially available ultrafiltration membranes under a high operating pressure.
“This is like 3-D printing with microorganisms,” Jun said.
“We can add whatever we like to the bacteria nanocellulose during its growth.