Due to natural and production activities, mercury contamination has become one of the major environmental problems in the world. Adsorption is one of the important means to solve this problem. However, most of the commercially available adsorbents exhibit relatively low adsorption capacity and slow kinetics. Therefore, a novel 4,6-diamino-2-mercaptopyrimidine-functionalised Zr-based metal-organic framework (UiO-66-DMP) was synthesised in this study. The UiO-66-DMP was characterised through X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, X-ray photoelectron spectroscopy, Fourier-transform infrared spectrometry, and thermogravimetric analysis. The potential of the UiO-66-DMP as a superior adsorbent for Hg(II) removal and the corresponding mechanisms were evaluated through batch experiments under different conditions and density functional theory calculations. Benefitting from its high specific surface area and multiple adsorption sites, the maximum Hg(II) adsorption capacity achieved in this study was 822.00 mg·g-1, which is the highest Hg(II) adsorption capacity reported to date. In addition, under the interference of Ca(II), Cd(II), Co(II), Mg(II), Mn(II), Ni(II), Cr(III), Cu(II), Zn(II) and other coexisting ions, the UiO-66-DMP could still maintain the high selective adsorption capacity for Hg(II). According to the characterization analysis and DFT calculation results, the adsorption of Hg(II) onto the UiO-66-DMP was dependent on electrostatic and covalent interactions between metal ions and abundant functional groups on the UiO-66-DMP surface.

中文翻译：

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一种经 4,6-二氨基-2-巯基嘧啶修饰的新型 Zr-MOF，可实现出色的 Hg (II) 去除效果


由于自然和生产活动的影响，汞污染已成为世界上主要的环境问题之一。吸附是解决这一问题的重要手段之一。然而，大多数市售吸附剂表现出相对较低的吸附容量和缓慢的动力学。因此，本研究合成了一种新型的4,6-二氨基-2-巯基嘧啶功能化的Zr基金属有机骨架（UiO-66-DMP）。通过 X 射线衍射、扫描电子显微镜、能谱分析、X 射线光电子能谱、傅里叶变换红外光谱和热重分析对 UiO-66-DMP 进行了表征。通过不同条件下的批量实验和密度泛函理论计算，评估了UiO-66-DMP作为优异的Hg(II)去除吸附剂的潜力以及相应的机制。得益于其高比表面积和多个吸附位点，本研究实现的最大Hg(II)吸附容量为822.00 mg·g-1，这是迄今为止报道的最高Hg(II)吸附容量。此外，在Ca(II)、Cd(II)、Co(II)、Mg(II)、Mn(II)、Ni(II)、Cr(III)、Cu(II)、Zn(II)的干扰下)和其他共存离子时，UiO-66-DMP仍能保持对Hg(II)的高选择性吸附能力。根据表征分析和DFT计算结果，UiO-66-DMP对Hg(II)的吸附取决于金属离子与UiO-66-DMP表面丰富官能团之间的静电和共价相互作用。