Enhanced adsorption performance of magnetic NiZnFeO/ZnCoO nanocomposites for the removal of malachite green dye.

This investigation reports the synthesis and characterization of (1-x)NiZnFeO/(x)ZnCoO nanocomposites, with 0.0 ≤  ×  ≤ 0.5. Fourier transform infrared (FTIR) and Raman spectroscopies confirmed the purity of the samples and the presence of bands corresponding to octahedral and tetrahedral iron occupancies for NiZnFeO nanoparticles. A shift in peak positions of these bands was detected upon the addition of ZnCoO nanoparticles. The magnetic properties of the nanocomposites were examined using Mössbauer spectrometry at both room temperature and 77 K. Room temperature analysis showed the existence of both ferromagnetic and superparamagnetic behaviors, while at 77 K, all nanocomposites showed ferromagnetic behavior. The adsorption performance of the nanocomposite on the removal of malachite green (MG) dye solution was investigated by varying the contact time, adsorbent concentration, and reaction temperature. The adsorption reaction followed the second-order kinetics and the sample with x = 0.3 showed the highest adsorption rate. The adsorption rate showed an increase with the increase in the reaction temperature. The adsorption isotherm was determined by applying different adsorption isotherms (Langmuir, Freundlich, and Temkin isotherms), and the results are well-fitted with the Langmuir theoretical model.