Fast recovery of Au (III) and Ag(I) via amine‐modified zeolitic imidazolate framework‐8

Abstract

In this paper, zeolitic imidazolate framework‐8 modified by the ethanediamine (NH2‐ZIF‐8) was employed for adsorbing Au (III) and Ag(I) from aqueous solutions. The adsorption capacities of NH2‐ZIF‐8 towards Au (III) and Ag(I) were found to be significantly affected by the pH values of the solution. The adsorption kinetics studies show that NH2‐ZIF‐8 presents a fast adsorption property towards metals, attaining 93% of adsorption equilibrium uptake for Au (III) within the first 30 min. This phenomenon can be ascribed to the coordination interaction between the amino group and Au (III). The thermodynamic data suggest that the adsorption of NH2‐ZIF‐8 towards Au (III) is endothermic process, while that for Ag(I) is exothermic. The maximum adsorption capacities of NH2‐ZIF‐8 toward Au (III) and Ag(I) can be achieved to 357 mg·g−1 and 222.25 mg·g−1, respectively. The metal ions interference results show that Cu (II) and Ni (II) hardly have no interference on Au (III) adsorption in e‐waste containing 1500 mg·l−1 Cu (II),100 mg·l−1 Ni (II) and 10 mg·l−1 Au (III); while for Ag(I), Cd (II) and Zn (II) have little interference on Ag(I) adsorption in the hybrid solutions containing Ag(I), Ni (II), Cd (II) and Zn (II) with equal concentration (50 mg·l−1), but Ni (II) interference most. The XPS study shows that partial Au (III) was reduced to Au(I), and that Ag(I) was completely reduced to Ag(0) during the adsorption process. The abundant of active sites of NH2‐ZIF‐8 containing C=N, N‐H, and Zn‐OH groups play a key role in the adsorption of Au (III) and Ag(I). In addition, electrostatic interaction can be responsible for the adsorption of Au (III) by NH2‐ZIF‐8. The regeneration experiments results show that the adsorption capacities of NH2‐ZIF‐8 towards Au (III) and Ag(I) can maintain after three cycles. This work provides a reliable method to improve the adsorption kinetics for metal ions.

Chitosan-poly(m-phenylenediamine) membranes for efficient gold recovery from acidic aqueous solutions

“…CS/PmPD membranes can process up to 410 mg g −1 of Au( iii ), which is comparable to previously reported values (Table S1, ESI†). 10,12,25–40…”

Cr-Based MOF for Efficient Adsorption of Au at Low Concentrations

“…Yuan et al used UiO-66-Schiff to recover Co­(II) with high selectivity in a mixed solution containing Na + , K + , Mg 2+ , Ca 2+ , Co 2+ , and Ni 2+ . Zhou et al utilized NH 2 -ZIF-8 for selectively adsorbing Ag­(I) in a mixture of Ag­(I), Ni­(II), Cd­(II), and Zn­(II) . The above-mentioned research indicated that MOFs exhibited huge potential in metal ion adsorption due to controllable chemical functionality .…”

“…30 Zhou et al utilized NH 2 -ZIF-8 for selectively adsorbing Ag(I) in a mixture of Ag(I), Ni(II), Cd(II), and Zn(II). 31 The above-mentioned research indicated that MOFs exhibited huge potential in metal ion adsorption due to controllable chemical functionality. 32 Unfortunately, as far as we know, the related study of MOFs focusing on absorbing Au at low concentration in complex solutions has rarely been reported (Figure 1).…”

Thiol-Functionalized Zr Metal–Organic Frameworks for Efficient Removal of Fe ³⁺ From Water

“…1 Poisonous heavy metal ions can cause serious diseases such as Minamata disease 2 ;t h e r e f o r e ,p r ocesses for the treatment and removal of these ions are well established. [3][4][5][6][7] However, the capture and recycling of essential nutrient metal ions have been studied to a limited extent, despite their critical roleinthefunctioningofthehumanbody.…”