Removal of Methylene Blue from Aqueous Solution by Manganese Oxide Nano-Sheets

MnO2 nanosheets were synthesized with tetramethylamine, H2O2, MnCl2·4H2O and its suspension were prepared for its high efficient removal of methylene blue (MB). MB removal reached as high as 95% when MB concentrations were less than 500 mg/L at pH 11. The adsorption data fitted better with Freundlich isotherm model than Langmuir model indicating the heterogeneous adsorption nature of MB on MnO2 nanosheets. The maximum adsorption capacity of MnO2 nanosheets was ~4,300 mg/g, which is the highest reported so far. The MnO2 nanosheets suspension was aggregated as precipitates after adsorption of MB. Our results demonstrated that dispersive MnO2 nanosheets have a potential application on adsorption of organics from solution with strong base and high salinity.