Semi-permeable graphene based membrane.

What it does

The composite membrane based on HSMG® graphene (High Strength Metallurgical Graphene) is used for water filtration purpose. Due to its semi-permeable it may by one day one of key elements in water treatment system.

Your inspiration

During my graduate studies, I dealt with the separation of graphene from the growth substrate and its investigation. Having developed a method for obtaining large layers of monolayer graphene, I started work on graphene based membranes that would be able to filter pollutants and could solve the extremely important problem of drinking water shortage in the world.

How it works

The basis of the membrane operation is quasimonocrystalline graphene synthesized by the metallurgical method (HSMG®), which in its structure has original clusters of subnanometric defects with a size of 0.2-0.7 nm in an amount of the order of 10^14 cm^− 2. Graphene is the active part of the membrane and is responsible for its semi-permeable nature and filtration properties. Large graphene defects are selectively sealed with another carbon material - reduced graphene oxide. The whole thing is placed on a thin porous substrate that acts as a scaffolding for graphene.

Design process

The identification of subanometric defects in its atomic structure prompted the idea of producing a membrane based on HSMG® graphene. Initially, the filtration properties of a membrane constructed on the basis of graphene on a carrier substrate were tested, but due to large defects occurring at the stage of synthesis and transfer, effective filtration was not possible. To eliminate this drawback, reduced graphene oxide was used as a medium to selectively seal these defects. Subnanometric defects responsible for filtration were not covered, which made water flow possible. The membranes were tested in cooperation with the Lodz University of Technology and Amii Sp. z o.o. under the grant POIR.04.01.04–00-0089 / 15 and showed a semi-permeable nature. After characterizing the membrane in terms of material and filtration properties, this solution was patented due to its novelty and originality.

How it is different

Compared to the currently used reverse osmosis membranes, membranes based on graphene HSMG® have a monatomic active layer thickness, which will make them more efficient and reduce the pressure required for the process. The conductive nature of graphene means that it can also be used in the innovative technology of electric-assisted membrane filtration, where these membranes, during conducted tests, showed a high desalination degree. Using carbon materials the potential for biofouling and development of battery colonies is limited.

Future plans

The intended use of composite graphene membranes is desalination and filtration of water (including, ultimately, sea water). Initially, the membranes need to be scaled up to achieve greater efficiency. I hope to develop a product that is efficient enough to be successfully used in drinking water filters. Due to the properties of graphene, which are the thickness of one atom and thus low mass, one can imagine the use of a graphene-based membrane even in a handy filtering bottle.

Awards

Special award of the Marshal of the Świętokrzyskie Voivodeship in the Student Inventor competition, 12th edition.