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Au Ions Capture Made Easier

Covalent organic frameworks (COFs) could be a perfect platform for extracting or detecting metal ions, thanks to their huge surface area and diverse functional building units.

Au Ions Capture Made Easier
Mechanism of 3D COFs. Image Credit: Shanghai Advanced Research Institute

Nevertheless, most 3D COFs have interpenetration as the presence of non-covalent communications among the adjacent nets, leading to reduced surface areas and porosities, and thus restricts their applications in molecular/gas adsorption and catalysis.

In recent times, a study group headed by Prof. ZENG Gaofeng and Assoc. Prof. XU Qing from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences has built a new non-interpenetration 3D COF for Au ions capture through imine bonds in the frameworks. The high surface area and ample cavities offered high Au3+ capacity (570.18 mg g-1), selectivity (99.5%), and efficiency (68.3% adsorption of utmost capacity in 5 minutes).

 On April 23rd, 2023, Advanced Functional Materials published this research.

The synthesized BMTA-TFPM-COF showed decent crystallinity with dia topology and a high Brunauer-Emmett-Teller (BET) surface area of 1,924 m2 g-1. Notably, the open cavities and exposed C=N bonds from non-fold interpenetration add up to selectivity, stability, and high capacity of Au3+ uptake.

The mechanism of Au capture was exhibited by the experiment. The protonated C=N bonds, as a result of the influence of the HAuCl4 and the protonated nitrogenous groups, were able to adsorb AuCl4 and minimize Au(III) to Au(I) and Au(0) in an acidic solution. Hence, the BMTA-TFPM-COF with ample exposed C=N bonds can encourage the transformation from Au(III) to Au(I) and Au(0) via the protonated C=N bonds, which additionally confirmed that the C=N bonds could take part in the reduction of Au(III).

This research provides a new understanding of the development of 3D COFs for Au3+ capture.

Journal Reference:

Liu, M., et al. (2023). Non‐Interpenetrated 3D Covalent Organic Framework with Dia Topology for Au Ions Capture. Advanced Functional Materials.


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