Fast Removal of Reactive Red 141 and Reactive Yellow 81 From Aqueous Solution by Fe3O4 Magnetic Nanoparticles Modified With Ionic Liquid 1-Octyl-3-methylimidazolium Bromide

Fe3O4 magnetic nanoparticles modified with 1-Octyl-3-methylimidazolium bromide([C8MIM]-Fe3O4) were used for the removal of reactive red 141 (RR141) and reactive yellow 81 (RY81) as model azo dyes from aqueous solution. The mean size and the surface morphology of the nanoparticles were characterized by TEM, XRD and FTIR techniques. Adsorption studies of two dyes were performed under different experimental conditions in batch technique. The adsorption of dyes onto [C8MIM]-Fe3O4 nanoparticles was affected by the initial pH, dye concentration, adsorbent amount, contact time and temperature. Experimental results indicated that [C8MIM]-Fe3O4 nanoparticles removed more than 98%. The maximum adsorption capacity of [C8MIM]-Fe3O4 for the Langmuir model was 71.4 mg g−1 and 62.5 mg g−1 for RR141 and RY81, respectively. The isotherm evaluations revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. Adsorption processes onto [C8MIM]-Fe3O4 nanoparticles were spontaneous exothermic and endothermic for RY81 and RR141, respectively. Dyes were desorbed from nanoparticlesby NaCl solution 0.1 mol L−1 at 80 and 30 °C for RR141 and RY81, respectively.