Nail Saleh Al Sailah, N. Narayanan Binitha
Being teratogenic, mutagenic, and carcinogenic, the removal of toxic Malachite Green (MG) dye from water is an intense area of research. Here, a hydrothermal technique is used for the facile preparation of magnetic nickel ferrite nanoparticles in the presence of Tween 20, which are used as adsorbents for the removal of MG dye from water. The structural, magnetic, and morphological investigations of the NiFe2O4 nanoparticles were studied using various characterization techniques, where the nanooctahedral morphology and magnetic nature of the cubic NiFe2O4 spinel structure are revealed using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS). The effects of pH, time, initial dye concentration, and adsorbent dosage on MG adsorption are investigated to find out the most suitable conditions of adsorption. The adsorption isotherms and kinetics of MG adsorption have also been investigated, which helped to elucidate the mechanism of adsorption. The NiFe2O4 displayed a monolayer adsorption capacity of 20.46 mg/g and fits the Langmuir model, and a pseudo-second-order kinetic model is suggested for the adsorption, revealing a homogeneously adsorbed monolayer of MG onto the surface of the adsorbent. NiFe2O4 showed an incredible degree of selectivity in the adsorption of MG from a solution of MG and methyl orange. The prepared NiFe2O4 is distinguished by a great ease of separation from water, enabling repeated usage.