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Posted: Feb 16, 2015
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 Fe3O4 modified graphene. On the other hand, graphene can prevent Fe3O4 agglomeration and enhance the removal efficiency because of its huge specific surface area and two-dimensional single-sheet structure.
The removal efficiency of E. coli for G-Fe3O4 composite can achieve 93.09%, whereas it is only 54.97% with Fe3O4 nanoparticles.
In addition, the G-Fe3O4 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.
Moreover, a detailed verification test of real water samples was conducted and the removal efficiency of bacteria in real water for G-Fe3O4 composite can also reach 94.8%. The removal mechanism of G-Fe3O4 was also investigated.