College of Chemistry and Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, PR China.
Interdisciplinary Nanoscience Center, Aarhus University, DK-8000, Aarhus C, Denmark.
Chemosphere. 2020 Aug;252:126578. doi: 10.1016/j.chemosphere.2020.126578. Epub 2020 Mar 23.
In the past few years, two-dimensional (2D) nanomaterials have emerged great potential for the removal of valuable metals and the capture of polluted-heavy metals. Herein, hierarchically flower-like microcrystals with 2D WS nanosheets (F-WS MCs) were prepared by one-pot hydrothermal synthesis strategy and its adsorption performances for precious metals were systematically assessed. The excellent adsorption efficiencies of ∼86.8%, ∼27.6%, and ∼94.1% towards Ag (I), Pd (II), and Au (III) respectively were achieved within 120 min, and the adsorption curves were in good agreement with a pseudo-second-order kinetic model showing a fast uptake rate at the optimum pH values (1.30 for Au (III), 1.43 for Ag (I), and 3.20 for Pd (II)). The adsorption isotherm followed well in the Langmuir model with the maximum removal capacities (q) of 186.2 mg g for Ag (I), 67.29 mg g for Pd (II), and 1340.6 mg g for Au (III), respectively. Furthermore, for recycling purposes, the relevant desorption solution was investigated with different ratios of monobasic acid and thiourea, suggesting the best desorption efficiency of 93.03%, 88.08%, and 85.34% for Ag (I), Pd (II), and Au (III), respectively. By characterizing the crystalline phase, and micromorphology element mapping of F-WS MCs before and after adsorption, the strong affinity and significant adsorption-reduction were indicated to dominate the adsorption process. Therefore, this work broadens the application range of WS microcrystals, providing an alternative material for capturing precious metals and wastewater treatment applications.
在过去的几年中,二维(2D)纳米材料在去除有价值的金属和捕获污染重金属方面显示出巨大的潜力。在此,通过一步水热合成策略制备了具有二维 WS 纳米片的分级花状微晶(F-WS MCs),并系统评估了其对贵金属的吸附性能。在 120 分钟内,分别对 Ag(I)、Pd(II)和 Au(III)实现了约 86.8%、27.6%和 94.1%的优异吸附效率,并且吸附曲线与伪二阶动力学模型吻合良好,表明在最佳 pH 值(Au(III)为 1.30、Ag(I)为 1.43 和 Pd(II)为 3.20)下具有较快的吸附速率。吸附等温线很好地符合 Langmuir 模型,最大去除容量(q)分别为 186.2 mg g 用于 Ag(I)、67.29 mg g 用于 Pd(II)和 1340.6 mg g 用于 Au(III)。此外,为了回收目的,研究了不同比例的一元酸和硫脲的相关解吸溶液,分别对 Ag(I)、Pd(II)和 Au(III)的解吸效率为 93.03%、88.08%和 85.34%。通过对吸附前后 F-WS MCs 的晶体相和微观形貌元素映射进行表征,表明强亲和力和显著的吸附还原作用主导了吸附过程。因此,这项工作拓宽了 WS 微晶的应用范围,为捕获贵金属和废水处理应用提供了一种替代材料。