Synthesis of UiO-66-OH zirconium metal-organic framework and its application for selective extraction and trace determination of thorium in water samples by spectrophotometry

Zahra Safaei Moghaddam; Massoud Kaykhaii; Mostafa Khajeh; Ali Reza Oveisi

doi:10.1016/j.saa.2018.01.010

Synthesis of UiO-66-OH zirconium metal-organic framework and its application for selective extraction and trace determination of thorium in water samples by spectrophotometry

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Apr 5:194:76-82. doi: 10.1016/j.saa.2018.01.010. Epub 2018 Jan 5.

Authors

Zahra Safaei Moghaddam¹, Massoud Kaykhaii², Mostafa Khajeh³, Ali Reza Oveisi³

Affiliations

¹ Department of Chemistry, Faculty of Sciences, University of Sistan and Baluchestan, Zahedan 98135-674, Iran.
² Department of Chemistry, Faculty of Sciences, University of Sistan and Baluchestan, Zahedan 98135-674, Iran. Electronic address: kaykhaii@chem.usb.ac.ir.
³ Department of Chemistry, University of Zabol, Zabol, Iran.

PMID: 29331822
DOI: 10.1016/j.saa.2018.01.010

Abstract

In this study, a zirconium-based metal-organic framework (Zr-MOF), named UiO-66-OH, was synthesized by the solvo-thermal method and characterized by Fourier transform-infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). This Zr-MOF was then employed as a sorbent for selective extraction and preconcentration of thorium ions after their complexation with 2‑(2,4‑dihydroxyphenyl)‑3,5,7‑trihydroxychromen‑4‑one (morin) from environmental water samples prior to its spectrophotometrical determination. The experimental parameters affecting extraction, such as pH of sample solution, amount of Zr-MOF, type and volume of eluting solvent, adsorption and desorption time, and concentration of complexing agent were evaluated and optimized. Under the optimized conditions, an enrichment factor of 250 was achieved. The limit of detection was calculated to be 0.35μg·L^-1 with a linear range between 10 and 2000μg·L^-1of thorium. The maximum sorption capacity of MOF toward thorium was found to be 47.5mg·g^-1. The proposed procedure was successfully applied to the analysis of real water samples.

Keywords: Solid-phase extraction; Spectrophotometry; Thorium; UiO-66-OH; Water analysis; Zirconium-based metal-organic framework.