Carboxypyridine-Functionalized MOFs for Enhanced Au(III) Recovery

Abstract

In this work, functional organic ligands are incorporated into the structurally stable metal–organic framework (UiO-66-SPA) to regulate the electrostatic potential and coordination positions of its inner and outer surfaces. The gold extraction efficiency of functionalized MOFs from acidic gold-containing wastewater is 2.65 times that of non-functionalized UiO-66-(SH)₂. In this way, efficient recovery of Au(III) in complex trace Au(III) wastewater is achieved. After multiple regeneration cycles, UiO-66-SPA still maintains 99% of its adsorption capacity. Through characterization techniques such as X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, kinetics, and thermodynamics, it is confirmed that the adsorption of Au(III) by UiO-66-SPA involves the synergistic effect of chelation coordination. This work provides a way to enhance adsorption for the post-modification of MOFs. The experiment of recovering Au(III) from industrial simulated wastewater improves the experimental data for the application of this material in Au(III) recovery. The research in this article is of great significance for MOFs materials in environmental protection, sustainable development of non-renewable resources, and green development of Au(III) resources.