Membranes - Page 15

Firmus SAM has been granted a patent for a novel electronics manufacturing method using graphene and other two-dimensional carbon crystals similar to graphene. Firmus expects to deploy graphene's potential in desalination, water treatment and contaminant removal, and will also explore other applications in electronics and other areas.

Firmus has a production facility in Warsaw, Poland and plans to use that for its graphene program.

A group of researchers from the University of Texas in El Paso (UTEP) developed a new technology to recycle water - based on graphene membranes. The researchers won $100,000 from the University of Texas System Horizon Fund Student Investment Competition and established a new company called American Water Recycling (AWR) to commercialize this technology. This follows an earlier $10,000 win in March 2013.

AWR claims that their graphene membrane can extract grease from water and clean it - and much faster than existing membranes. In fact, a regular membrane can process about 30 gallons a day, but the graphene based membranes will do 30 gallons per hous. AWR is now applying to a $300,000 state grant that will allow them to test the membrane in a year-long trial at a septic-tank pumping company in Las Cruces. According to their business plan, they will reach $33 million in sales in the next five years and will also develop other water-treatment and water-recycling products.

Lockheed Martin says that they have developed a new energy-efficient graphene-based water desalination technology. Lockheed developed new graphene filters that has nanometer-sized holes in them that allow water to pass through - but not salt molecules. The energy required to "push" seawater through these filters is very low because graphene is so thin. In fact graphene is 500 times thinner than the filter available today, and this filter will require about 100 times less energy. Lockheed patented the new filtration system, and calls the new material Perforene.

Simulated nanoporous graphene filtering salt ions

Lockheed is not ready to commercialize this technology yet. They are still refining the process for making the holes in graphene, and also the production process of the graphene itself. They expect to have a prototype filter by the end of 2013. This prototype will be a drop-in replacement for current filters used in reverse osmosis (RO) plants. They hope to commercialize this technology by 2014-2015 and are looking for partners in the filter manufacturing arena.

Researchers from MIT and the Oak Ridge national Laboratory (ORNL) developed a promising new graphene-based membrane that can be useful to filter microscopic contaminants from water or for drug delivery. The membrane features high flux and tunability (i.e. it can quickly filter fluids but also be easily tunable to let certain molecules through while stopping others).

To develop the membrane, the team fabricated a 25 square millimeter graphene sheet using CVD. They managed to transfer the sheet to a polycarbonate substrate dotted with holes. They thought that the graphene will be totally impermeable, but experiments proved that salts can flow through the membrane.

Earlier this month we reported on a new& research by the University of Colorado Boulder that demonstrated new efficient graphene membranes that be used to make natural gas production more efficient, and reduce CO2 emissions.

AZoNano posted an interview with Professor Scott Bunch from UCB regarding graphene, this interesting research and its findings, and what's holding off commercialization.

Researchers from UT Dallas have managed to shrink the size of a graphene pore to less than one nanometer - small enough to thread a DNA strand. This can be useful for DNA sequencing.

The researchers used new technique to manipulate the size of the pore, by using an electron beam from an advanced electron microscope and in-situ heating up to 1200 degree Celsius temperature. They say that this is the first time that a graphene nanopore has been controlled. The next step is to build a prototype device to sequence DNA.

Update: here's an interview with the professor who conducted this interesting research.

Researchers from the University of Colorado Boulder demonstrated that graphene membranes with tiny pores can effectively and efficiently separate gas molecules through size-selective sieving. Such membranes could one day be used to make natural gas production more efficient, and reduce CO2 emissions from power plant exhaust pipes.

The researchers used ultraviolet light-induced oxidative "etching" to introduce nanoscale pores in graphene sheets. They measured permeability of various gases across the membranes. The membrane can be used to separate gases based on molecular size. Graphene is an ideal material for separation membranes because it's durable but does not require a lot of energy to push molecules through it.

MIT scientists have shown (in simulations) that nanoporous graphene can filter salt from water at a rate that is 2-3 orders of magnitude faster than today’s best commercial desalination technology, reverse osmosis (RO). This could lead to more efficient and smaller water desalination facilities.

Simulated nanoporous graphene filtering salt ions

The graphene is used as a membrane material that allows a flow of water with full salt refection via size exclusion. Other materials have been investigated for the same purpose, but the researchers say that graphene is the "ultimate" thin membrane as it's the thinnest one possible and as water flux across a membrane scales inversely with the membrane’s thickness.

Researchers at the University of Delaware suggest that graphene sheets with nanopores (tiny holes) could be used for ultrafast DNA sequencing based on tiny holes. The study which is based on computer simulation suggests that threading DNA though nanopores can be used to detect the presence of different DNA bases. This is done by a current of ions flowing vertically through the pore or an electronic current flowing transversely through the graphene.

Graphene is just one atom thick and so the nanopore has contact with only a single DNA base. The researchers suggest using nanoribbons of graphene to enable fast and low-cost (less than $1,000) DNA sequencing.

A team of researchers led by Professor Sir Andre Geim demonstrated a graphene-Oxide based membrane that is impermeable to all gases and liquids (i.e. it's vacuum-tight) - but water can evaporate though it as if there's no membrane at all.

The researchers explain: "Graphene oxide sheets arrange in such a way that between them there is room for exactly one layer of water molecules. They arrange themselves in one molecule thick sheets of ice which slide along the graphene surface with practically no friction. If another atom or molecule tries the same trick, it finds that graphene capillaries either shrink in low humidity or get clogged with water molecules."