Highly efficient magnetic separation of organic dyes from liquid water utilizing Fe3O4@graphene composites

The Fe3O4@graphene composites was prepared by a simple hydrothermal strategy for efficient removal of organic dyes from liquid water. The effects of solution pH, contact time, adsorbent dosage and initial dye concentration on the adsorption performance of Fe3O4@graphene composites were systematically studied and the maximum adsorption capacities of Methyl orange (MO), Rose Red B (RB), Malachite green (MG), Congo red (CR) and Crystal Viollet (CV) on Fe3O4@graphene magnetic composites were found to be 144.9, 105.2, 59.9, 77.9 and 208.3 mg.g(-1), respectively. The adsorption studies indicated that pseudo-second-order model could depict adsorption kinetics very well and that Langmuir isotherm model could describe isotherms well. The adsorption capacity of organic dyes on Fe3O4@graphene composites decreases with adsorption-desorption cycling, but still remains more than 42% of its initial adsorption capacity after 5 cycles. The results suggest that combining the high porousity structure, lightweight, and high surface area of graphene composites with the super-paramagnetic property of Fe3O4, the prepared Fe3O4@graphene composites is promising candidate for removal of organic dyes pollutions from water effectively.