Role of Fe3O4 magnetite nanoparticles used to coat bentonite in zinc(II) ions sequestration

The use of natural bentonite (NB) coated with synthesized Fe3O4 magnetite nanoparticles (CB) was first investigated for its significance as an adsorbent to sequester zinc(II) ions in aqueous phases. The characterization study demonstrated a substantial improvement in several adsorptive parameters of NB, like surface area, surface morphology, and active sites, post coating. From the analysis of the pore sizes, the CB were observed to exhibit a highly mesoporous appearance. Batch experiments demonstrated that the removal efficiency of the Zn(II) onto the CB was affected by various factors, such as the CB dosage, initial concentration, and reaction time. Furthermore, the adsorption process increased when the pH values were close to neutral. The experimental isotherm data fitted well onto the Langmuir model with the maximum amount of Zn(II) (22.573 mg/g) being adsorbed at pH 6, when the CB dose was 0.8 g and it shaking was done at 200 rpm speed, in a reaction time of 120 min. The kinetics parameters were studied using the Brouers-Sotolongo fractal theory with its derived empirical kinetics equations. The results revealed that the Hill model, introduced with a time-dependent fractal time, is the best fit for the experimental kinetics data. From the results of this study, it appears that the CB can be used as a potential agent in the adsorption systems for the remediation of the Zn(II)-rich wastewater.