Removal of fluoride ions from water using MgO-based materials with special emphasis on MgO/PPy nanocomposites: A review

Fluorine (F^-) ions are naturally occurring in the environment, becoming life-threatening due to their increased concentration in water released fromindustry. The WHO (World Health Organization) has recommended a fluoride concentration of 1.5 mg/L as safety guidance in drinking water. Excessive fluoride ions in drinking water sources pose a persistent threat to public health, leading to dental and skeletal fluorosis in affected populations. Here we review, some magnesium oxide-based materials and nanocomposites with special emphasis on magnesium oxide/polypyrrole (MgO/PPy) nanocomposites, which have attracted the attention of researchers for addressing this challenge. This review focuses on drinking water treatment by fluoride ions removal using these nanocomposites, with a discussion about the presence of fluorine ion in wastewater, their sources, their implications on human health, and techniques for the removal of these ions from wastewater with a focused discussion on the adsorption of fluorine ions using MgO/PPy nanocomposites. Future perspectives about the removal of these ions have been discussed, to sum up the review.