Two lanthanide-based metal–organic frameworks for highly efficient adsorption and removal of fluoride ions from water

Abstract

The contamination of water with fluoride (F⁻) is a source of mounting concern for global public health, and the removal of fluoride is quite important and challenging. In this study, two new lanthanide-based metal–organic frameworks (MOFs), {[Ce(L1)_0.5(NO₃)(H₂O)₂]·2DMF} (1) and [Eu₃(L2)₂(OH)(DMF)_0.22(H₂O)_5.78]·guest (2) (H₄L1 = 2,5-di(3′,5′-dicarboxylphenyl)benzene and H₄L2 = 3,5-bis(isophthalic acid)-1H-1,2,4-triazole) are designed, synthesized and characterized. Both MOFs are tested for their adsorption capacity for fluoride ions and different uptake times from contaminated water. The investigation indicates that 1 displays a much higher adsorption capacity (103.95 mg g⁻¹) and faster uptake rates (1.79 g mg⁻¹ min⁻¹) for fluoride ion than that of 2. The presented investigation is the first report in which lanthanide-based MOFs are used for the removal of fluoride ions from water.