Facile preparation and dye removal properties of Fe3O4@carbon nanocomposite

Fe3O4@carbon nanocomposite (Fe3O4@C) was continuously prepared by combining microreactor with pyrolysis reactor. The Fe3O4 nanoparticles homogeneously disperse in the carbon matrix with an average size of about 9.2 nm and narrow size distribution. The Fe3O4@C nanocomposite has a Brunauer–Emmett–Teller specific surface area of 71.9 m2/g and total pore volume of 0.37 cm3/g. This nanocomposite has a saturation magnetisation value of 16 emu/g and could be easily separated from water by an external magnet. With the increase of pH value or temperature, the Rhodamine B absorbing capacity of the Fe3O4@C nanocomposite first increases and then decreases after a certain value. The absorbing capacity at pH value 9 is about 169 mg/g when the temperature is 20°C. The above said value also exceeds 150 mg/g at pH value 3. The capacity is still higher than 120 mg/g after four regenerations. The absorbing capacity even reaches to 184 mg/g at 60°C of the absorbing temperature.