Magnetic Mesoporous Carbons Derived from in Situ MgO Template Formation for Fast Removal of Heavy Metal Ions

In this paper, magnetic mesoporous carbon composites were prepared by calcination of the mixture of magnesium citrate and Fe3O4@ SiO2 in an inert atmosphere. A high content of Fe3O4@ SiO2 and MgO was in situ embedded in a carbon matrix. After removing the MgO template by diluted acid, the resulting material (Fe3O4@ SiO2@ mC) was subjected to further H2O2 oxidation treatment. The formed oxygen-containing functional groups on the products provided plenty of active sites for the adsorption of analytes of interest. The obtained composites (Fe3O4@ SiO2@ mC-H2O2) exhibited a mesoporous structure with a high specific surface area of 731 m(2) g(-1). The adsorption capacities of Fe3O4@ SiO2@ mC-H2O2 for Cu(II) and Pb(II) were calculated to be 86.5 and 156 mg g(-1), respectively. Under optimal conditions, the adsorption isotherm of Cu(II) and Pb(II) onto Fe3O4@ SiO2@ mC-H2O2 fitted the Langmuir model and the adsorption kinetic was well-correlated with the pseudo-second-order model. Besides, Fe3O4@ SiO2@ mC-H2O2 exhibited fast removal dynamics (within less than 1 min) for Cu(II) and Pb(II), demonstrating great application potential in wastewater treatment.