Membranes - Page 2

Researchers from Peking University, Beijing Normal University and KU Leuven recently reported a novel method to substantially reinforce large-area graphene membranes. Their work provides a facile method to fabricate large-area graphene membranes and paves the road to practical application in the membrane separation field. 

Nanoporous graphene membranes are attractive for molecular separations, but it remains challenging to maintain sufficient mechanical strength during scalable fabrication and module development. In this work, the team drew inspiration from the composite structure of cell membranes and cell walls, and designed a large-area atomically thin nanoporous graphene membrane supported by a fiber-reinforced structure with strong interlamellar adhesion. It was found that factors like fracture stress, fracture strength, and tensile stiffness of the composite membranes can be enhanced compared with other graphene-based membranes of large scale.

Researchers from the Indian Institute of Technology Madras (IIT Madras) and Tel Aviv University in Israel, have developed a graphene oxide-doped silica aerogel adsorbent that can remove trace pollutants from wastewater.

This graphene-modified silica aerogel reportedly removes over 76% of trace pollutants (PPM level) in continuous flow conditions, offering a sustainable path for large-scale water purification. The research team is dedicated to enhancing these results for large-scale applications.

U.K.-based Evove, which develops graphene-enhanced membrane and filtering solutions, has announced it has completed a pilot demonstrating the use of its filter technology at a large AB InBev brewery in Johannesburg, South Africa. 

It was explained that making beer is a process that requires a lot of water: Just sterilizing the equipment in a brewery can mean using thousands of gallons of water every week. That’s especially problematic in a place like drought-prone Johannesburg, where a water shortages and leaky infrastructure mean that water can be in short supply. Normally, the hot, caustic water used to clean tanks and water lines at a brewery can’t be reused, and ends up in the sewer system. It’s filled with grain residues, sugars, and yeasts that can’t easily be filtered out. “With conventional filters, it just clogs up the filters right away,” says Andrew Walker, Evove’s chief marketing officer.

Researchers from The University of Warwick, the University of Manchester, Brazil's Universidade Federal do Ceara and Turkey's Izmir Institute of Technology have tackled the long-standing conundrum of why graphene is so much more permeable to protons than expected by theory. 

A decade ago, scientists at The University of Manchester demonstrated that graphene is permeable to protons, nuclei of hydrogen atoms. The unexpected result sparked a debate because theory predicted that it would be extremely hard for a proton to permeate through graphene's dense crystalline structure. This had led to suggestions that protons permeate not through the crystal lattice itself, but through the pinholes in its structure.

Researchers at  Oak Ridge National Laboratory (ORNL) and Arizona State University have developed a technique that combines two approaches to nanofabrication - top-down and bottom-up methods - to enable atomic-scale precision manufacturing using a focused electron beam.

Top-down methods, such as lithography, employ external influences to modify materials. While they offer precision patterning, their resolution is often constrained by factors like beam size and scattering effects. On the other hand, bottom-up methods capitalize on the spontaneous self-assembly of atoms and molecules through chemical reactions, granting atomic-level control. However, the positioning in this method tends to be random rather than directed.
The novel technique demonstrated on twisted bilayer graphene (TBG) harmoniously integrates these two approaches.

A team of researchers from Japan's Chiba University, led by Associate Professor Tomonori Ohba and including master’s students, Mr. Kai Haraguchi and Mr. Sogo Iwakami, has fabricated fullerene-pillared porous graphene (FPPG)—a carbon composite comprising nanocarbons—using a bottom-up approach with highly designable and controllable pore structures. 

Separation processes are essential in the purification and concentration of a target molecule during water purification, removal of pollutants, and heat pumping. To make the separation processes more energy efficient, improvement in the design of porous materials is necessary. Porous carbon materials offer a distinct advantage as they are composed of only one type of atom and have been well-used for separation processes. They have large pore volumes and surface areas, providing high performance in gas separation, water purification, and storage. However, pore structures generally have high heterogeneity with low designability, which poses various challenges, limiting the applicability of carbon materials in separation and storage.

Graphene-Info is happy to give the stage to talented young graphene researchers, especially with such commitment and passion as Roberto Pezone from TU Delft, who has agreed to chat with us and answer a few questions about his background, work and collaboration with the Graphene Flagship.

Roberto Pezone checking a wafer at its initial fabrication stages

Q: Thank you for this interview Roberto! Very nice to e-meet you. We know you have been involved with graphene research for some time, can you give us a quick overview of your graphene research interests and projects?

Thank you for the opportunity to discuss my research. Within the Graphene Flagship's Work Package 6 (core 3), my primary focus lies in integrating graphene into sensors, particularly microphones. My main objective is to develop methods that enable the seamless integration of graphene on a wafer-scale while thoroughly exploring the advantages and disadvantages associated with such approaches.

In addition to developing fabrication techniques, I am also highly interested in characterizing the potential of graphene for acoustic devices. This type of research plays a crucial role in bridging the gap between graphene's exceptional properties and its practical utilization in the industry, unlocking higher performance and new sensor concepts.

UK-based Evove, developer of a graphene-based water filtration technology designed to tackle water shortage, has announced that it has secured £5.7 million (around USD$6,750,000) in a round of funding led by One Ventures with participation from AM Ventures and existing investors.

Evove says it will use the funds to expand its manufacturing capacity, scale up its 3D-printed membrane process, and capitalize on its substantial pipeline of opportunities. 

SoundCell, a spin-off of TU Delft, has secured funding of €350,000 from proof-of-concept fund UNIIQ, together with Delft Enterprises. The funds will go towards facilitating the development of its graphene technology for single cell resolution antibiotic sensitivity testing.

SoundCell develops innovative technology that can measure the vibrations produced by living bacteria. This technology makes use of graphene membranes and could have significant implications for the detection and prevention of antibiotic resistance, as it would enable patients to receive effective medication against bacterial infections faster than today’s standard.

Researchers from Australia's Monash University and CSIRO Manufacturing have designed a permselective membrane based on reduced graphene oxide (rGO) for making practical lithium-sulfur batteries. 

The membrane closely mimics a cell plasma membrane, demonstrating selective Li+ transport and the ability to not only retain polysulfides, but also 're-activate' them on the membrane's electrochemically active interface. The team used the membrane to demonstrate high loading and high rate Li-S batteries, also on a pouch cell level.