Angew:卟啉基1D-COFs

文摘   2024-10-10 00:00   北京  

本文要点:

  1. 贵金属是化工行业的宝贵材料,但它们很稀缺,有供应中断的风险。从废物中回收贵金属是一种很有前途的策略,这里我们巧妙地利用光照作为一种环保节能的辅助策略来促进贵金属离子的还原,从而提高吸附容量和动力学。

  2. 合成了一种新的光敏共价有机框架(PP-COF)来说明这种光辅助策略的有效性和可行性。

  3. 光照下PP-COF对金、铂和银离子的平衡吸附容量分别为4729、573和519mg·g–1,分别是黑暗条件下吸附容量的3.3、1.9和1.2倍。

  4. 值得注意的是,采用PP-COF的过滤柱可以在光照下回收模拟电子废物浸出液中超过99.8%的金离子,1克PP-COF可以从高达0.15吨的电子废物浸出液中回收金。

  5. 有趣的是,光照下PP-COF捕获的贵金属主要存在于微米级颗粒中,很容易被萃取分离。我们相信这项工作将有助于贵金属回收和资源循环利用的循环经济。

Figure 1. (a) Synthesis of PP-COF by Schiff-base condensation reaction. (b) PXRD patterns of PP-COF with Pawley refinement. (c) FT-IR spectra of PP-COF, Pyd, and Por. (d) Solid-state 13C NMR spectrum of PP-COF. Nitrogen sorption isotherm (e) and pore size distribution profile (f) of PP-COF calculated from the non-local density functional theory. (g) Crystal model and measured pore size of PP-COF.  

Figure 2. (a) Mott–Schottky plots of PP-COF. (b) UPS spectrum of PP-COF. (c) The band structure diagram of PP-COF and the standard reduction potentials of three PMx+. (d) Photocurrent response curves of PP-COF. Typical signals of •O2 – (e) and 1O2 (f) in EPR spectra derived from PP-COF. (g) ELF contours focus on the N sites of PP-COF. (h) The adsorption potential energies between PMx+ ions and three types of N in PP-COF. 

Figure 3. Adsorption isotherms of PP-COF for AuCl4 – (a), PtCl4 2– (b), and Ag+ (c) under dark and light irradiation conditions. 5.0 mg of PP-COF was used for the adsorption in 10 mL of PMx+ solutions with different concentrations. Adsorption versus time curves of PP-COF for AuCl4 – (d), PtCl4 2– (e), and Ag+ (f) under dark and light irradiation conditions. 20.0 mg of PP-COF was used for the adsorption in 100 mL of 50 ppm PMx+ solutions for kinetic study.

Figure 4.XPS spectra of PP-COF after adsorbing AuCl4 – (a), Ag+ (b), and PtCl4 2– (c). XRD patterns of PP-COF after adsorbing AuCl4 – (d), Ag+ (e), and PtCl4 2– (f). SEM and EDS element mapping images of PP-COF after adsorbing AuCl4 – (g) and Ag+ (h) with light irradiation.

Figure 5.The fs-TA spectra of PP-COF (a) and PP-COF + AuCl4 – (b) at 400 nm excitation. (c) Comparison of kinetics of PP-COF and PP-COF + AuCl4 –. The different pump-probe time delays are chosen to highlight the changing nature of the excited electronic states for PP-COF (d) and PP-COF + AuCl4 – (e). (f) The proposed mechanism for reducing PMx+ ions to PM0 with light irradiation.

Figure 6. (a) The performance of PP-COF (20.0 mg) for AuCl4 – (3 ppm based on Au concentration) recovery in the simulated e-waste leachates with light irradiation. (b) The selectivity of PP-COF for AuCl4 – recovery in the solution with mixed metal ions with light irradiation. 10.0 mg of PP-COF was used for the adsorption in a 10 mL ion mixture solution (The concentration of each ion is 100 ppm) for the selectivity study. (c) Reusability of PP-COF for AuCl4 – recovery.

https://doi.org/10.1002/anie.202414943


内容来源于COF催化在线。


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