1 research outputs found
Thiol-Functionalized Zr-Based Metal–Organic Framework for Capture of Hg(II) through a Proton Exchange Reaction
Rational design and
facile synthesis of thiol-modified metal–organic
frameworks (MOFs) for the efficient capture of highly toxic mercuric
ions from water has attracted great attention. However, the corresponding
adsorption mechanism is not well understood. In this paper, a thiol-modified
Zr-based MOF (Zr-DMBD) with free-standing and accessible thiol groups
was prepared. It exhibited remarkable performance in the capture of
HgÂ(II), and its maximum adsorption capacity was 171.5 mg·g<sup>–1</sup>, approximately 9 times that of the pristine UiO-66.
Impressively, the maximum value of the selective coefficient was as
high as 28899.6. Additionally, 99.64% of HgÂ(II) could be eliminated
by Zr-DMBD from the actual wastewater, rendering the concentration
of Hg (II) below 0.05 ppm (Emission Standard of Mercury (GB30770-2014)).
The excellent adsorption capacity and outstanding selectivity were
ascribed to the remarkable coordination between S<sup>2–</sup> and HgÂ(II), as supported by the results of FT-IR and XPS. Unexpectedly,
a good correlation (R<sup>2</sup> = 0.982) between the increased H<sup>+</sup> concentration after adsorption and its corresponding adsorption
capacity was obtained. This result suggested that the thiol groups’
sulfur atoms coordinated with HgÂ(II) while the hydrogen atoms in thiol
groups were replaced and released as hydrogen ions in the solution,
thus extending a proton exchange reaction mechanism for HgÂ(II) adsorption