Magnetic graphene composite used to remove pathogens from water

(Nanowerk News) Among the various techniques used to remove bio-organic pollutants in water, such as physical processes (adsorption, distillation, and filtration), biological processes (activated sludge), chemical processes (flocculation and chlorination), and photocatalytic process, the application of nanomaterials in water has been extensively studied because of its small size effect, quantum size effect, huge surface effect, good mechanical properties, and so on in recent years.

However, because of its small size, it is difficult to separate nanomaterials from water, which not only resulted in difficulty to recycle and reuse nanomaterials but also may generate serious secondary pollutions.

So far, graphene composites were used to remove metal heavy and organic dye; however, there is no report to cleaning pathogens bacteria in water with Fe 3 O 4 modified graphene. On the other hand, graphene can prevent Fe 3 O 4 agglomeration and enhance the removal efficiency because of its huge specific surface area and two-dimensional single-sheet structure.

A new paper in ACS Applied Materials & Interfaces ("Highly Efficient Removal of Pathogenic Bacteria with Magnetic Graphene Composite") reports the successful synthesis of Fe 3 O 4 /graphene (abbreviated as G-Fe 3 O 4 ) nanoparticles by solvothermal method to effectively remove both bacteriophage and bacteria.

The removal efficiency of E. coli for G-Fe 3 O 4 composite can achieve 93.09%, whereas it is only 54.97% with Fe 3 O 4 nanoparticles.

In addition, the G-Fe 3 O 4 composite show high removal efficiency for a wide range of pathogens including not only bacteriophage ms2, but also various bacteria such as S. aureus, E. coli, Salmonella, E. Faecium, E. faecalis, and Shigella.