Alkaline earth metal doped nickel ferrites as a potential material for heavy metal removal from waste water

Water pollutants especially heavy metals are very harmful to the ecosystem even at low concentrations. For the effective removal of heavy metals (lead and cadmium), nickel ferrite, and alkaline earth metals doped nickel ferrite were synthesized using the co-precipitation method. The synthesized adsorbents were characterized using XRD, BET, FESEM-EDX, FTIR, VSM, UV-Vis, and XPS analytical techniques. Batch adsorption studies were performed with different parameters of adsorption such as pH, contact time, dosage of adsorbent, and concen-tration of heavy metal ions solution for a period of 60 min at room temperature. Removal percentage of Pb(II) and Cd(II) ions is 83% and 45% in case of nickel ferrite and reached to 97% and 80% for doped nickel ferrites. Isothermal studies were conducted using linear and non-linear equations of Langmuir and Freundlich isotherm models. The adsorption isotherm data was better fitted in linear Langmuir model (correlation coefficient, R-2 = 0.99446 for Pb(II) and 0.96682 for Cd(II) ions) than Freundlich model (R-2 = 0.85171 for Pb(II) and 0.73917 for Cd(II) ions). The kinetics studies for Pb(II) and Cd(II) ions adsorption were conducted using nonlinear pseudo -first-order, second-order, and intraparticle diffusion models. The process of adsorption of heavy metals can be adequately described by a pseudo-second order model with correlation coefficient (R-2) of 0.98823 and 0.98248 for Pb(II) and Cd(II) ions. The findings revealed that prepared mesoporous ferrites (as per BET analysis) act as an efficient adsorbents to remove heavy metals from wastewater along with good recyclability and easy separation under the influence of an external magnetic field.

Automated summary

Water pollutants, especially heavy metals, are highly harmful to the ecosystem even at low concentrations. In this study, nickel ferrite and alkaline earth metals doped nickel ferrite were synthesized as efficient adsorbents for the removal of lead and cadmium from wastewater. The synthesized adsorbents were extensively characterized, and batch adsorption studies were conducted to determine the optimal conditions for adsorption. The results showed that the doped nickel ferrites achieved higher removal percentages compared to nickel ferrite alone. Isothermal and kinetics studies were also performed to understand the adsorption behavior of heavy metals. The findings demonstrated that the prepared mesoporous ferrites have excellent adsorption properties, recyclability, and easy separation under an external magnetic field.