Synthesis of NiCo2O4 nanostructures with different morphologies for the removal of methyl orange

Aiming to investigate the adsorption removal performance of NiCo2O4 as water purification adsorbents, magnetic materials NiCo2O4 with six different morphologies were successfully synthesized by a facile method. NiCo2O4 with six different morphologies were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption-desorption, vibrating sample magnetometry and X-ray energy dispersive spectrometry. In this study, we mainly explored the effect of specific surface area, pore volume and pore size on the performance for the removal of methyl orange, and the adsorption capacity followed an order of (b) NiCo2O4 nanorods > (e) balsam-like NiCo2O4 > (f) rose-like NiCo2O4 > (d) NiCo2O4 nanoribbons > (a) NiCo2O4 flowerlike nanostructures > (c) dandelion-like NiCo2O4 spheres. The results indicated that NiCo2O4 nanorods exhibited better adsorption performance. The reasons for the excellent adsorption capacity of NiCo2O4 nanorods were also discussed in depth by analyzing scale and surface characteristics. Besides, NiCo2O4 could be easily recovered from solution, which may avoid potential secondary pollution. Moreover, adsorption kinetics, the influence of pH and adsorption mechanism were comprehensively investigated. This finding indicated that NiCo2O4 were promising adsorbents for water purification.