Water scarcity is a huge problem across the globe. Clean drinking water is even more scarce. In a move that could be a global game-changer for countries like India, where clean drinking water is a big issue, a team of researchers including an Indian American engineer has found a way to use graphene oxide sheets to transform dirty water into drinking water.
“We hope that for countries where there is ample sunlight such as India, you’ll be able to take some dirty water, evaporate it using our material, and collect fresh water,” said Srikanth Singamaneni from Washington University in St. Louis, Missouri. The novel approach combines bacteria-produced cellulose and graphene oxide to form a bi-layered biofoam.
“The process is extremely simple,” Singamaneni said. “The beauty is that the nanoscale cellulose fiber network produced by bacteria has excellent ability move the water from the bulk to the evaporative surface while minimizing the heat coming down, and the entire thing is produced in one shot,” he added. “The design of the material is novel here,” the researcher added.
“You have a bi-layered structure with light-absorbing graphene oxide filled nanocellulose at the top and pristine nanocellulose at the bottom. When you suspend this entire thing on water, the water is actually able to reach the top surface where evaporation happens,” he explained.
Light radiates on top of it, and it converts into heat because of the graphene oxide — but the heat dissipation to the bulk water underneath is minimized by the pristine nanocellulose layer. “You don’t want to waste the heat; you want to confine the heat to the top layer where the evaporation is actually happening,” Singamaneni said. The cellulose at the bottom of the bi-layered biofoam acts as a sponge, drawing water up to the graphene oxide where rapid evaporation occurs. The resulting fresh water can easily be collected from the top of the sheet.
Professor Singamaneni joined the Washington University in St. Louis faculty in January 2010. From 2006 to 2009, he was a graduate research assistant in Professor Vladimir V. Tsukruk’s lab. He is the recipient of a National Science Foundation CAREER Award (2013), Dean’s Faculty Award for Innovation in Research (2013), MRS graduate student Gold Award (Fall 2008), Materials Research Society Best-Poster Award (Spring 2007) and departmental creative and scholarly award at Western Michigan University in 2004. Professor Singamaneni has co-authored over 85 refereed articles in archival journals, eight invited reviews, six book chapters and a book.
Professor Singamaneni’s research interests include Plasmonic engineering in nanomedicine (in vitro biosensing for point-of-care diagnostics, molecular bioimaging, nanotherapeutics), photovoltaics (plasmonicallyenhahced photovoltaic devices), surface enhanced Raman scattering (SERS) based chemical sensors with particular emphasis on the design and fabrication of unconventional and highly efficient SERS substrates, hierarchical organic/inorganic nanohybrids as multifunctional materials, bioinspired structural and functional materials, polymer surfaces and interfaces, responsive and adaptive materials and scanning probe microscopy and surface force spectroscopy of soft and biological materials.