Researchers develop method to control graphene nanochannel orientation and dimensions for improved membranes and filters

A team of Brown University researchers has found a way to orient the gaps that form between sheets of graphene that are stacked on top of each other. The tiny gaps, called nanochannels, are positioned by the team in a way that makes them more useful for filtering water and other liquids of nanoscale contaminants.

Structure and fabrication steps leading to vertically aligned Zr-GO/epoxy membranes imageStructure and fabrication steps leading to vertically aligned Zr-GO/epoxy membranes. Image from article

“In the last decade, a whole field has sprung up to study these spaces that form between 2D nanomaterials,” said Robert Hurt, a professor in Brown’s School of Engineering and coauthor of the research. “You can grow things in there, you can store things in there, and there’s this emerging field of nanofluidics where you’re using those channels to filter out some molecules while letting others go through.”

Researchers shed light on ionic interactions with graphene and water

Researchers led by Northwestern University engineers and Argonne National Laboratory scientists have reached new findings regarding the role of ionic interaction within graphene and water. Their insights could open the door to the design of new energy-efficient electrodes for batteries or provide the backbone ionic materials for neuromorphic computing applications.

"Every time you have interactions with ions in matter, the medium is very important. Water plays a vital role in mediating interactions between ions, molecules, and interfaces, which lead to a variety of natural and technological processes," said Monica Olvera de La Cruz, Lawyer Taylor Professor of Materials Science and Engineering, who led the research. "Yet, there is much we don't understand about how water-mediated interactions are influenced by nanoconfinement at the nanoscale."

Researchers develop enhanced graphene sieve that could advance clean water efforts

Vanderbilt engineers recently designed a simple defect-sealing technique to correct variations in pore size in graphene membranes. The researchers reported a breakthrough in scalable fabrication of graphene membranes with a sealing technology that corrects variations in the pore size so they remain small enough to trap salt ions and small molecules but allow water to pass.

Vanderbilt engineers design a defect-sealing technique to correct variations in pore size in graphene membranes image

One of the most complex engineering challenges when making membranes so thin is to maintain integrity in the uniformity of the pores, which requires drilling atomically precise holes in a one-atom thick sheet of carbon atoms. “A single large hole can cause high leakage and compromise membrane performance,” said Piran Kidambi, assistant professor of chemical and biomolecular engineering.

Chinese researchers develop graphene face mask for 48-hour use

Chinese researchers from AECC Beijing Institute of Aeronautical Materials (AECC BIAM) have developed a new type of face mask with graphene material on the key filter layer. The researchers have reportedly put a graphene-polypropylene material on the melt-blown fabric, which is the key filter layer of masks.

The graphene material is said to help the masks features stronger antibacterial properties, better air permeability and enhanced durability. The graphene face mask makes use of the nanoknife effect of the graphene material to destroy the cell wall of bacteria.

Researchers use graphene to resolve a known imaging impediment

Researchers at NIST have used a graphene membrane to solve a long-standing problem affecting the understanding of both living cells and batteries. When a solid and an electrically-conducting liquid come into contact, a thin sheet of charge forms between them. Although this interface, known as the electrical double layer (EDL), is only a few atoms thick, it plays a central role in a wide range of systems, such as keeping living cells nourished and maintaining the operation of batteries, fuel cells, and certain types of capacitors.

Graphene barrier solves imaging issue image

For instance, the buildup of an EDL on a cell membrane creates a difference in voltage between the liquid environs outside the cell and the cell's interior. The voltage difference draws ions such as potassium from the liquid into the cell, a process essential for the cell's survival and ability to transmit electrical signals.