Selective and highly efficient recovery of Au(III) by poly(ethylene sulfide)-functionalized UiO-66-NH2: Characterization and mechanisms

Enrichment of gold (Au) from wastewater is an efficient use of non-renewable resources and can reduce environmental pollution. Here, A new adsorbent (UiO-66-ES) is created that efficiently captures Au(III) in simulated wastewater by altering UiO-66-NH2 with poly(ethylene sulfide). The adsorbent was success-fully prepared as confirmed by FT-IR, SEM, EDS, BET, XRD and XPS. At 318 K and a pH of 4.0, the highest removal ability of UiO-66-ES for gold ions is 723.005 mg/g. Kinetic studies revealed that Au(III) chemisorption on UiO-66-ES was the main driving force in the process. The recovery of Au(III) by UiO-66-ES happened as a monolayer adsorption over a uniform surface, according to the isotherm investiga-tion. Meanwhile, thermodynamic analyses revealed that the adsorption is a heat-absorbing and natural phenomenon. Moreover, after four adsorption-desorption cycles, UiO-66-ES still achieved 89.83% adsorption and 86.43% desorption. In simulated wastewater comprising seven metallic ions, the adsor-bent is extremely specific for Au(III). The adsorption mechanism of Au(III) includes electrostatic attrac-tion, chelation, and reduction, according to zeta and XPS data. Since its high adsorption capacity, great selectivity, and good repeatability, UiO-66-ES is projected to be used in the practice of gold (Au) recovery from wastewater.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, a new adsorbent (UiO-66-ES) was created to efficiently capture gold ions from simulated wastewater. The adsorbent was successfully prepared and confirmed through various tests. UiO-66-ES exhibited high adsorption capacity and repeatability, making it a promising candidate for gold recovery from wastewater.