Synthesis of NiFe2O4 nanoparticles for removal of anionic dyes from aqueous solution

NiFe2O4 nanoparticles (NiFe2O4 NPs) were synthesized and characterized using X-ray diffraction, transmission electronic microscopy (TEM), pHpzc and Brunauer, Emmett, and Teller methods. Size of the nanostructures according to TEM was obtained around 12 nm. The prepared NiFe2O4 NPs was used as an adsorbent for the removal of anionic dyes of Sunset Yellow, Tartrazine, and Eriochrome Black T from aqueous solutions. It was found that removal percentage significantly depends on the level of initial solution pH. The adsorption of anionic dyes on to NiFe2O4 NPs was investigated from both equilibrium and kinetic point of view. Kinetic experiments were performed at three values of initial dyes concentration in the solution and the results of fitting to the experimental data by the non-linear methods represent that fractal-like pseudo-second-order model can describe the kinetics of adsorption. Among the various conventional isotherm models, Langmuir–Freundlich is more suitable for analyzing the explanation data. The adsorption capacities of Sunset Yellow, Tartrazine, and Eriochrome Black T on NiFe2O4 NPs were 107.1, 104.8, and 81.52 mg/g, respectively. Also, the method was applied to the removal of dyes in real samples (tap water, river water, and candy).