University of Illinois team finds that defects in graphene membranes may improve biomolecule transport

Researchers at the University of Illinois examined how tiny defects in graphene membranes, formed during fabrication, could be used to improve molecule transport. They found that the defects make a big difference in how molecules move along a membrane surface. Instead of trying to fix these flaws, the team set out to use them to help direct molecules into the membrane pores.

Nanopore membranes have generated interest in biomedical research because they help researchers investigate individual molecules - atom by atom - by pulling them through pores for physical and chemical characterization. This technology could ultimately lead to devices that can quickly sequence DNA, RNA or proteins.

Graphene may be the key to next-gen membranes that filter c02

A way to cut CO2 levels, produced from burning fossil fuels and released into the atmosphere, is through carbon capture, a chemical technique that removes CO2 from emissions ("postcombustion"). The captured CO2 can then be recycled or stored in gas or liquid form, a process known as sequestration.

Graphene helps co2 filtering membranes get more efficient imageCO2-selective polymeric chains anchored on graphene effectively pull CO2 from a flue gas mixture. Credit: KV Agrawal (EPFL)

Carbon capture can be done using high-performance membranes, which are polymer filters that can specifically pick out CO2 from a mix of gases, such as those emitted from a factory's flue. These membranes are environmentally friendly, they don't generate waste, they can intensify chemical processes, and can be used in a decentralized fashion. They are now considered as one of the most energy-efficient routes for reducing CO2 emissions. Now, scientists (led by Kumar Varoon Agrawal) at Ecole Polytechnique Federale de Lausanne (EPFL) have developed a new class of high-performance membranes that exceed post-combustion capture targets by a significant margin. The membranes are based on single-layer graphene with a selective layer thinner than 20 nm, and have highly tunable chemistry, meaning that they can pave the way for next-generation high-performance membranes for several critical separations.

Graphene oxide layers made to mimic biological channels may clean up pharmaceuticals production

KAUST researchers have tailored the structure of graphene-oxide layers to mimic the shape of biological channels, creating ultra-thin membranes to rapidly separate chemical mixtures. This may have the potential to inspire new materials to clean up chemical and pharmaceutical production.

2D-dual-spacing channel membranes for high performance organic solvent nanofiltration image

"In making pharmaceuticals and other chemicals, separating mixtures of organic molecules is an essential and tedious task," says Shaofei Wang, postdoctoral researcher in Suzana Nuñes lab at KAUST. One option to make these chemical separations faster and more efficient is through selectively permeable membranes, which feature tailored nanoscale channels that separate molecules by size.

Chinese researchers achieve photo-induced ultrafast active ion transport through graphene oxide membranes

Researchers from the Chinese Tsinghua University and CAS demonstrated a coupled photon-electron-ion transport phenomenon through graphene oxide membranes. Using the energy of light, cations are able to move thermodynamically uphill over a broad range of concentrations, at rates orders of magnitude faster than that via simple diffusion.

Based on this mechanism, the team further developed photonic ion switches, photonic ion diodes, and photonic ion transistors as the fundamental elements for active ion sieving and artificial photosynthesis on synthetic nanofluidic circuits.

CPI, Haydale and others collaborate on Smart Filter project

The Centre for Process Innovation (CPI) has collaborated on a project to advance the development of a low-cost, self-cleaning coating technology for industrial filter membranes.

CPI, Haydale and others collaborate on Smart Filter project image

The Smart Filter project used graphene and its derivatives to create a coated filter membrane that offers increased resistance to fouling for industrial waste water treatment. Membrane filters are used in a number of industrial separation applications but are afflicted by fouling, which typically lowers throughput or increases energy consumption, and reduces filter life. Focusing upon oil water separation and nuclear waste water treatment, the collaboration, with G2O Water Technologies, Haydale and Sellafield, developed a repeatable, reproducible and scalable process to make coated filter membranes, which delivered a 30% improvement in permeability when compared to an equivalent uncoated filter.