Novel thymine-functionalized MIL-101 prepared by post-synthesis and enhanced removal of Hg2+ from water

A novel thymine-functionalized MIL-101 (MIL-101-Thymine) material was synthesized using a post-synthesis method to remove mercury at a high efficiency. MIL-101-Thymine was successfully prepared in this work and was confirmed by several characterization methods, such as 13 C nuclear magnetic resonance, X-ray diffraction, and infrared spectroscopy. The Hg 2+ adsorption agreed well with the Langmuir model, and the maximum adsorption capacity was 51.27   mg/g. The adsorption rate fit with the pseudo-second-order kinetic model. Furthermore, MIL-101-Thymine exhibited excellent selectivity towards Hg 2+ over other cations, and the maximum value of the selective coefficient reached 947.34; this result is very likely due to the highly selective interactions of T-Hg 2+ –T in MIL-101-Thymine. The result of X-ray photoelectron spectroscopy also showed that Hg 2+ was coordinated with the N of thymine in MIL-101-Thymine. Moreover, the results of the thermogravimetric analysis and adsorption experiments showed that the Hg atom was two-coordinated with the thymine group. MIL-101-Thymine was used to remove trace Hg 2+ in real water samples, and satisfactory recoveries were obtained.