Manganese ferrite based materials for wastewater treatment: Mechanisms, performance, and future perspectives

Spinel nanoferrites, in particular Manganese ferrites (MnFe 2 O 4 ), have gained a lot of attention due to their exceptional magnetic, structural and catalytic properties. In this review, we have critically examined the recent advancement in MnFe 2 O 4 nanoferrites and their composites for the removal of organic and inorganic pollutants using the processes like adsorption and catalytic degradation. The parameters like high surface area, tunable surface chemistry and redox-active Mn 2 + /Fe 3+ centres contribute to the improved adsorption efficiency and generation of reactive oxygen species (ROS). Studies reported so far showed that the adsorption ability of MnFe 2 O 4 nanoferrites for the removal of heavy metals is greater than 300 mg/g and the removal efficiency for various dyes and pharmaceutical waste is greater than 90%. In addition, the magnetic characteristics of these nanoparticles enable the phenomenon like magnetic separation and reusability which further improve their waste water treatment capability. In this review, we have also discussed the role of their composite with carbon and other polymers in order to improve the stability, dispersion and catalytic performance. This review discusses the structure, property and performance relation for the MnFe 2 O 4 nanoferrites and their composites and also provide the future directions for the development of efficient and sustainable MnFe 2 O 4 based water purification technologies. However, certain challenges related to the aggregation, scalability and environmental impacts of nanoferrites remain the area of concern and needs further discussion.