One-pot synthesis of magnetically separable ordered mesoporous carbon

Ordered mesoporous carbon materials with magnetic frameworks have been synthesized via a "one-pot" block-copolymer self-assembly strategy associated with a direct carbonization process from resol, ferric citrate and triblock copolymer F127. The effects of iron loading on framework, pore features and magnetic properties of the resultant mesostructured maghemite/carbon composites were investigated by SAXS, WXRD, TEM, N-2 sorption, TG and magnetometer measurements. The results show that the mesoporous nanocomposites with a low gamma-Fe2O3 content (such as 9.0 wt%) possess an ordered 2-D hexagonal (p6mm) structure, uniform mesopores (similar to 4.0 nm), high surface areas (up to 590 m(2)/g) and pore volumes (up to 0.48 cm(3)/g). Maghemite nanocrystals with a small particle size (similar to 9.3 nm) are confined in the matrix of amorphous carbon frameworks. With the increase in gamma-Fe2O3 content, the surface area and pore volume of the nanocomposites decrease. The particle size of the gamma-Fe2O3 nanocrystals increases up to 13.1 nm. The iron oxide particles can extend from the carbon walls into mesopore channels, and hence bring a rough pore surface and gradually break down the mesoscopic regularity. The maghemite/carbon nanocomposites exhibit excellent superparamagnetic behaviors. The saturation magnetization strength can be easily adjusted from 2.5 to 12.1 emu/g by increasing the content of gamma-Fe2O3. Further H2O2 oxidation treatment of the magnetic nanocomposites endows plenty of oxygen-containing functional groups on the carbon surface, which improves their hydrophilic properties efficiently. The gamma-Fe2O3 particles, embedding into the carbon matrix, show high stability during the H2O2 oxidation process. Such modified nanocomposites with hydrophilic and magnetic framework show evidently improved adsorption properties of water and fuchsin base dye molecules in water and an easy separation procedure.