Porous MgO nanoplates were successfully synthesized through a facile and cost-effective precursor
calcination method. The as-prepared porous MgO nanoplates were characterized by X-ray diffraction,
scanning electron microscopy, transmission electron microscopy, and BrunauereEmmetteTeller measurements.
The fluoride removal performance of the porous MgO nanoplates has been investigated. The
fluoride adsorption rate of the absorbent was very fast, and the adsorption kinetics could be fitted into a
pseudo-second-order model. The adsorption isotherm can be well fitted in Freundlich model, while the
adsorption capacity was over 185.5 mg/g at pH 7. Furthermore, the porous MgO nanoplates can efficiently
remove fluoride from water in a wide pH range of 2e10, which is favorable for practical application.
The effect of co-existing anions on fluoride removal also has been investigated. The result
indicated that the existence of carbonate, bicarbonate and phosphate can influenced the fluoride
adsorption performance. Furthermore, the fluoride adsorption mechanism was investigated by the FTIR
and XPS analysis. The results show that both the hydroxyl and surface carbonates can exchange with
fluoride ions, revealing a hydroxyl and carbonate co-exchange mechanism. Moreover, the as-prepared
porous MgO nanoplates is quite stable, only less than 0.18% of the absorbent was dissolved during the
adsorption experiment. The results indicated that the as-prepared porous MgO nanoplates can be used as
a potential suitable candidate for fluoride removal.