## 5 Novel Magnetic Ferrite Nanoparticle Applications in Wastewater Treatment
### Magnetic Ferrite Nanoparticles' Application in Adsorption of Toxic Materials  
The selective adsorption method has emerged as an efficient and cost-effective way of recovering toxic materials from wastewater. Over the past years, different adsorbent materials have been used to remove water contamination [260]. Magnetic ferrite nanoparticles are one of the materials actively studied for such applications due to their magnetic nature. Moreover, magnetic ferrite nanoparticles offer high porosity, a large surface area, low cost, a significantly enhanced collection property, and ease of modification on the surface, which leads to a high selectivity of target species [24]. The adsorbent capacity of magnetic ferrite nanoparticles is influenced by various factors, e.g., adsorbent type, pH of water, concentration of adsorbent, surface area, surface functionality, and temperature of the system [24]. The adsorption of pollutant anions, cations, and organic molecules follows different mechanisms that are highly dependent on the surface functionality of nanoparticles and adsorbents (Figure 13). Typically, electrostatic interaction, ion exchange, and complex formations are primarily involved in the adsorption of ions from wastewater, while for the adsorption of organic molecules, physiochemical interactions of weak forces such as \(\pi\)-\(\pi\) bonding, van der Waals interactions, hydrogen, and dipole-dipole bandings are responsible [261]. The presence of heavy metals in wastewater \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Ferrite Photocatalyst** & \
\begin{tabular}{c} **Crystal** \\ **Structure** \\ \end{tabular} &
\begin{tabular}{c} **Synthesis** \\ **Method** \\ \end{tabular} & **Pollutant** & **Performance** & **Conditions** & **Ref.** \\ \hline ZnO/ZnFe\({}_{2}\)O\({}_{4}\) & Octahedral & Solvothermal & Methylene blue & 91.2\% & 120 min of UV-vis, & [242] \\ ZnCuFe\({}_{2}\)O\({}_{4}\) & Cubic & Corprecipitation & Methylene blue & 94\% & 135 min of UV-vis at PH9 & [238] \\ CoNiFe\({}_{2}\)O\({}_{4}\) & Cubic & Corprecipitation & Congo red & 94.8\% & 90 min under solar & [255] \\  & & & & & irradiance & \\ CNT/NiFe\({}_{2}\)O\({}_{4}\) & Cubic & ultra-sonication & Rhodamine B, & 83.87\% & & \\  & & method & methylene blue, & 90.80\% & 90 min under visible light & [248] \\ CuFe\({}_{2}\)O\({}_{4}\) & Cubic & Hydrothermal & Methyl orange & 90\% & 12 h exposure under Xeon & [256] \\ GO-CoFe\({}_{2}\)O\({}_{4}\) & Cubic & Hydrothermal & Acetamiprid & 97\% & - & [253] \\ Cu\({}_{x}\)Cd\({}_{1-x}\)A\({}_{20}\)Fe\({}_{1.8}\)O\({}_{4}\) & Cubic & Hydrothermal & Triazophos & 91.21\% & 100 min under 100 W & [254] \\  & & & & & visible irradiation & \\  & & & & & UV irradiation in the & \\ TiO\({}_{2}\)-ZrO\({}_{2}\) & Anatase & Sol–gel & Cu(II) and Cr (II) & 100\%, 91\% & presence of & [257] \\  & & & & & sacrificial agent & \\ TiO\({}_{2}\) NPs & Anatase & Sol–gel & Ibuprofen & 80\% & 90 min UV irradiation & [258] \\  & & & & & & \\ B-doped TiO\({}_{2}\) & Anatase & Sol–gel & Atrazine & 94.7\% & 180 min UV irradiation & [259] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of various modified ferrite nano materials used for photocatalytic wastewater treatment. causes severe issues for human life. These metals can directly pollute water reservoirs and indirectly affect human life via aquatic life and agriculture. They can damage the reproductive, liver, and nervous systems, as well as cause kidney failure, skin dermatitis, dyspnoea, lung carcinoma, etc. [262]. Magnetic ferrite nanoparticles can be suitable adsorbents for removing toxic metals. The key characteristics of magnetic ferrite nanoparticles for metal absorbance are their large surface area, high adsorption capacity, cost-effectiveness, abundance of active sites, and ease of separation via an external magnetic field. The electrostatic force of attraction between the adsorbate and the adsorbent is the main factor responsible for binding heavy metals to the adsorbent's surface [264]. [PERSON] et al.