Selective and rapid extraction of trace amount of gold from complex liquids with silver(I)-organic frameworks

Abstract

The design of adsorbents for rapid, selective extraction of ultra-trace amounts of gold from complex liquids is desirable from both an environmental and economical point of view. However, the development of such materials remains challenging. Herein, we report the fabrication of two vinylene-linked two-dimensional silver(I)-organic frameworks prepared via Knoevenagel condensation. This material enables selective sensing of gold with a low limit of detection of 60 ppb, as well as selective uptake of ultra-trace gold from complex aqueous mixtures including distilled water with 15 competing metal ions, leaching solution of electronic waste (e-waste), wastewater, and seawater. The present adsorbent delivers a gold adsorption capacity of 954 mg g−1, excellent selectivity and reusability, and can rapidly and selectively extract ultra-trace gold from seawater down to ~20 ppb (94% removal in 10 minutes). In addition, the purity of recovered gold from e-waste reaches 23.8 Karat (99.17% pure).

Tailoring stability, catalytic activity and selectivity of covalent metal–organic frameworks via steric modification of metal nodes

“…Metal–organic frameworks (MOFs) are a class of crystalline porous materials composed of metal ions/clusters and organic linkers, 14–18 and they have been considered as promising heterogeneous catalysts due to their atomically precise and periodic structures, the presence of coordinatively unsaturated sites or open metal sites, and intrinsic porosity. 19–24 More importantly, the chemical designability and tunability of MOFs potentially allowed chemists to explore the design principle for tuning catalytic performance along with molecular understanding. 25–28 Specifically, the catalytic performance of MOFs can be effectively mediated at a molecular level through several strategies including the modification of metal nodes, the introduction of organic linkers with functional groups, and the encapsulation of other active species.…”

Coordination directed metal covalent organic frameworks

“…For example, some recently reported crystalline porous materials were prepared by combining metal cluster with organic covalent bond formation. [38][39][40][41][42] However, these materials should be essentially classified as MOFs rather than MCOFs since they do not have covalently-linked networks. In contrast, despite the coordination directed MCOFs starting from coordination compound building units, the organic components are still composed of light elements and connected by covalent bonds.…”

Pyrazine Functionalization in Eu-MOF for Exclusive Ratiometric Luminescence Sensing of PO43–

“…Metal–organic frameworks (MOFs), composed of metal ions/clusters and organic linkers, are a class of crystalline porous coordination polymers. − Owing to their tunable pore sizes, variable surface functions, and large surface areas, MOFs have drawn widespread attention from scientists around the world for the past decades, for example, in the field of luminescence sensing. ,, Lanthanum-based MOFs (Ln-MOFs) are deemed promising candidates for tracking trace amounts of analytes due to their exceptionally strong rare-earth-based luminescence. ,− The single-emission luminescence quenching (turn-off) and luminescence enhancing (turn-on) can be easily realized in Ln-MOFs. − However, compared to ratiometric luminescence sensing, single-emission luminescence sensing is highly susceptible to environmental interference, limiting the scope of its practical applications. More importantly, the self-calibration of ratiometric luminescence sensors can significantly promote selective detection and accuracy in fluctuating environments. , Thus, the development of Ln-MOFs with highly stable ratiometric luminescence for on-site real-time detection is desirable.…”