The efficient enrichment and selection of Au are crucial
for gold
recovery. The adsorption technology is considered to have potential
due to the advantages of operation simplicity and green processability.
Nevertheless, the poor Au selectivity at low concentrations in complex
solutions limits the further application of the adsorption technology.
In this work, a novel Cr-based MOF adsorbent was successfully synthesized
using 1,2,4-triazole and 4-aminobenzoic acid as ligands. Benefitting
from the surface positive charge and extensive chelation and reduction
sites, the novel Cr-based MOF exhibited a total adsorption capacity
of up to 357 mg/g and excellent adsorption selectivity toward Au(III)
in the complex metal mixed solutions, such as simulated sewage ash
waste liquid and actual e-waste leachate. Furthermore, the adsorption
kinetics, isotherms, and thermodynamics were discussed in depth for
investigating the adsorption mechanisms of the MOF. The PXRD and XPS
analyses reveal that the adsorption process involves complexation,
redox, and electrostatic interactions. We believe that this study
of novel Cr-based MOF adsorbents for efficient Au adsorption is meaningful
for further application in the gold recovery technology from e-waste.