Department of Chemistry, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, P.O. Box 14115-175, Iran.
Dalton Trans. 2018 Oct 23;47(41):14549-14555. doi: 10.1039/c8dt03196g.
Considering the widespread production of Cr(vi) from various industrial processes and its damaging toxicity as a carcinogenic agent, it is imperative to investigate stable and efficient adsorbents with a rapid performance towards Cr(vi) adsorption. Zirconium-containing metal-organic frameworks (Zr-MOFs) have been recently used as environmentally friendly adsorbents for the reduction of metallic contaminants in aqueous media. Preparation from nontoxic metal sources, remarkable stabilities and distinguished physicochemical features, such as the high tendency of Zr-clusters to adsorb oxo-anions, beneficial structural defects, and modification of their properties via modulator synthesis, can be enumerated as the advantages of Zr-MOFs. In this study, we improved the adsorption capacity of UiO-66 as the most stable Zr-MOF for Cr(vi) adsorption from aqueous solutions through the gradual addition of an N-O functional group. This strategy ultimately led us to afford a new Zr-MOF structure (TMU-66) with a maximum Cr(vi) adsorption capacity of 60.241 mg g-1, which is 4 times the absorption capacity of UiO-66, and very fast kinetics (<3 min) that followed the pseudo-second-order kinetics. This study demonstrates that a conceptual design can be helpful in synthesizing safe and stable adsorbents with appropriate capacity and kinetics for adsorption.
考虑到 Cr(vi) 广泛存在于各种工业过程中，且具有致癌毒性，因此研究具有快速性能的稳定且高效的 Cr(vi) 吸附剂势在必行。含锆金属有机骨架（Zr-MOFs）最近已被用作环境友好型吸附剂，用于减少水介质中的金属污染物。无毒金属源的制备、显著的稳定性和独特的物理化学特性，如 Zr 簇吸附含氧阴离子的高趋势、有益的结构缺陷以及通过调节剂合成对其性质的修饰，均可作为 Zr-MOFs 的优点。在这项研究中，我们通过逐步添加 N-O 官能团，提高了 UiO-66 作为最稳定的 Zr-MOF 对水溶液中 Cr(vi) 的吸附容量。该策略最终为我们提供了一种新的 Zr-MOF 结构（TMU-66），其 Cr(vi) 吸附容量最大可达 60.241mg g-1，是 UiO-66 的 4 倍，且动力学非常快（<3min），符合准二级动力学。本研究表明，概念设计有助于合成具有适当容量和动力学性能的安全稳定吸附剂。
