Porous Lanthanum-Zirconium phosphate with superior adsorption capability of fluorine for water treatment

Bimetal oxide is a popular defluorinating material. Hexadecyl trimethyl ammonium bromide (CTAB) as a surfactant successfully synthesizes a novel lanthanum-zirconium phosphate to remove fluorine from groundwater. Lanthanum-zirconium phosphate at a Zr/La molar ratio of 2 exhibited a specific surface area of 455.14 m2/g with a wide pore size, which was achieved by incorporating lanthanum into mate-rials and removing CTAB through calcination. The maximum fluoride adsorption capacity is 109.17 mg/g, which is tenfold that of mesostructured zirconium phosphate. Specifically, analysis revealed that mZrP and LamZrP2-1 were amorphous, which is consistent with HAADF-STEM. The fluoride adsorption fitted well with the pseudo-second-order equation model and Langmuir isotherm mode. LamZrP2-1 had potent anti-interference ability without PO43-. Moreover, LamZrP2-1 was reusable for at least six cycles of adsorption-desorption with little influence. The adsorption mechanism of fluoride was discussed by X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance spectroscopy (NMR) analysis, and Fourier transform infrared (FTIR) spectroscopy. Fluoride was captured by LamZrP2-1 via charge attrac-tion, ligand exchange of different bond strengths, and ion exchange. Lanthanum-zirconium phosphate is important not only in the research and development of bimetal oxides but also in the treatment of groundwater for fluoride removal.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

Bimetal oxide is commonly used for defluorination, and a novel lanthanum-zirconium phosphate was successfully synthesized using CTAB as a surfactant to remove fluoride from groundwater. The lanthanum-zirconium phosphate showed a high specific surface area and a large pore size, with a maximum fluoride adsorption capacity ten times higher than that of mesostructured zirconium phosphate. The adsorption mechanism of fluoride by the lanthanum-zirconium phosphate was discussed using XPS, NMR, and FTIR analysis. Lanthanum-zirconium phosphate is important not only in the research and development of bimetal oxides but also in the treatment of groundwater for fluoride removal.