In situ synthesis of magnetic MnFe2O4/diatomite nanocomposite adsorbent and its efficient removal of cationic dyes

The novel magnetic MnFe 2 O 4 /diatomite composites were synthesized via a precipitation/hydrothermal method combined with alkali treatment. The microstructure and interface properties of the obtained composites were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and zeta potential analyzer. The adsorption behaviors of as received magnetic MnFe 2 O 4 /diatomite composite adsorbents for cationic dyes including methylene blue and basic fuchsine have been investigated in this study. The batch adsorption experiments showed that the adsorption process was very fast and the kinetic data well fitted with pseudo-second-order model. The adsorption isotherms well followed the Langmuir isotherm model, and the maximal adsorption capacity for methylene blue and basic fuchsine can reach 104.06 and 284.09   mg/g at 318   K, respectively. The adsorption behavior of the MnFe 2 O 4 /diatomite composite is an endothermic and spontaneous process. The magnetic MnFe 2 O 4 /diatomite composite can be a promising candidate as an adsorbent for the removal of cationic dyes from wastewater.