Graphene Oxide/Chitosan Composite for Methylene Blue Adsorption

Graphene oxide (GO) has been regarded as promising adsorbent in treating water pollution. However, the high dispersibility of GO makes the separation of adsorbent/pollutant composite from aqueous environment very difficult. In this study, GO was fabricated with chitosan (CS) for dye removal, where GO-CS composite was not dispersible in water and could be easily separated by filtration or low speed centrifugation. GO-CS was found to be good adsorbent of methylene blue (MB) with a huge adsorption capacity of 4.68 x 10(2) mg/g, ranking it among the most effective adsorbents of MB. The adsorption data of MB on GO-CS were well fitted to the Freundlich model, rather than the Langmuir model. When initial MB concentration was 100 mg/L, the MB solution could be decolorized to colorless by GO-CS. After the treatment, GO-CS/MB composite could be easily removed by filtration. The implications to the application of graphene based adsorbents in water treatment are extensively discussed.