Graphene is a material with extraordinary electrical and thermal conductivity, as well as high strength and high specific surface area, known as the “king of new materials”, often appearing in different forms in our daily life. With its single atomic layer two-dimensional structure showing subversive qualities, it is widely used in new energy, electronics, medical and other fields. Currently, the global graphene market is divided into two main categories: graphene oxide (GO) and graphene nanoparticles (GNP). As the large-scale production of graphene needs to go through multiple processes such as dispersion, reaction, purification and concentration. The initial graphene suspension obtained has a very low concentration (usually less than 1%) and contains unreacted chemicals, impurity ions and debris particles, so it is not easy to obtain high-purity, high-concentration graphene materials with stable properties.

 

So far, several fabrication routes for the production of graphene have been established, such as mechanical exfoliation, solvent exfoliation, chemical vapor deposition, crystal epitaxial growth and redox method. Mechanical exfoliation method is the initial discovery of graphene, this method is simple, low cost, but low yield, and difficult to obtain large area graphene, only for laboratory small-scale preparation and basic research. Chemical vapor deposition (CVD) is currently the main method for the preparation of large-area, high-quality graphene films, can accurately control the number of layers and quality of graphene, suitable for large-scale industrial production, but the cost is high, and the process requirements are strict. Redox method has low raw material cost, simple preparation process, and easy to mass production, but the structure and performance of reduced graphene have a certain gap compared with perfect graphene, and there are more defects.
However, ceramic membrane filtration systems show unique advantages in graphene concentration. The microporous structure of the ceramic membrane filters and separates the graphene feed solution driven by pressure differentials. When the graphene dispersion passes through the ceramic membrane, the impurity molecules and solvents pass through the membrane pores, while the graphene flakes are retained for concentration. The system has high filtration precision, which can accurately control the graphene particle size distribution and remove tiny impurities to ensure the purity and quality of the concentrated product; the operation is simple and stable, which can be carried out under normal temperature and pressure or under mild conditions to avoid destroying the structural properties of graphene; and it can also realize continuous production to meet the needs of large-scale production.

The modern ceramic membrane filtration system is integrated with intelligent control technology to realize accurate closed-loop adjustment of process parameters. The system analyzes the trans-membrane pressure difference and flux decay trend in real time, predicts the contamination node and triggers the cleaning procedure automatically, which not only reduces the labor cost significantly, but also ensures the consistency of each batch of products, providing a solid guarantee for the large-scale mass production of graphene.
The main value of ceramic membrane filtration system in graphene concentration is not only in the efficiency improvement, but also in the fine control of product quality. The more far-reaching value lies in opening the key bottleneck of graphene industrialization. The traditional process is limited by the concentration link, many downstream applications are difficult to carry out. The mature application of ceramic membrane technology makes the high quality graphene prepared by aqueous phase exfoliation method to be concentrated at low cost, and promotes its application in new energy batteries, heat dissipation materials, anticorrosive coatings and other high-end fields, which helps the development of high and new technology.