Fast recovery of Au (III) and Ag(I) via amine‐modified zeolitic imidazolate framework‐8
Fast recovery of Au (III) and Ag(I) via amine‐modified zeolitic imidazolate framework‐8
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DOI：
10.1002/aoc.5541
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发表时间：
2020-01
影响因子：
3.9
通讯作者：
Shuxi Zhou;Chenghong Hu;Weifeng Xu;Xiaohui Mo;Panliang Zhang;Yu Liu;K. Tang
中科院分区：
文献类型：
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作者：
Shuxi Zhou;Chenghong Hu;Weifeng Xu;Xiaohui Mo;Panliang Zhang;Yu Liu;K. Tang
本文采用乙二胺修饰的咪唑酸分子筛骨架- 8 （NH2‐ZIF‐8）吸附水溶液中的Au （III）和Ag(I)。NH2‐ZIF‐8对Au （III）和Ag(I)的吸附能力受溶液pH值的显著影响。吸附动力学研究表明，NH2‐ZIF‐8对金属具有快速吸附特性，在前30分钟内对Au （III）达到93%的吸附平衡吸收率。这种现象可归因于氨基与Au （III）之间的配位相互作用。热力学数据表明，NH2‐ZIF‐8对Au （III）的吸附是吸热过程，而对Ag(I)的吸附是放热过程。NH2‐ZIF‐8对Au （III）和Ag(I)的最大吸附量分别为357 mg·g−1和222.25 mg·g−1。金属离子干扰结果表明，Cu （II）和Ni （II）对含有1500 mg·l−1Cu （II）、100 mg·l−1Ni （II）和10 mg·l−1Au （III）的电子垃圾对Au （III）的吸附几乎没有干扰；Ag(I)、Ni （II）、Cd （II）和Zn （II）等浓度（50 mg·l−1）的混合溶液中，对Ag(I)、Cd （II）和Zn （II）的吸附干扰较小，而Ni （II）的干扰最大。XPS研究表明，吸附过程中部分Au（III）被还原为Au(I), Ag(I)被完全还原为Ag(0)。NH2‐ZIF‐8中含有丰富的C=N、N‐H和Zn‐OH基团的活性位点对Au （III）和Ag(I)的吸附起关键作用。此外，静电相互作用可能是NH2‐ZIF‐8吸附Au （III）的原因。再生实验结果表明，NH2‐ZIF‐8对Au （III）和Ag(I)的吸附能力经过3次循环后仍能保持。本研究为改善金属离子的吸附动力学提供了可靠的方法。
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−1and 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−1Cu (II),100 mg·l−1Ni (II) and 10 mg·l−1Au (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.