Amino-Modified ZIF-90 for Effective Adsorption of Au(III) in Environmental Water

In this work, amino-modified ZIF-90 (NH₂-ZIF-90) was prepared by using butylamine as a modifier, and its effectiveness in adsorbing Au(III) from environmental samples was investigated. The morphology and structure of NH₂-ZIF-90 were analyzed via SEM, XRD, FT-IR, and XPS. Optimal adsorption occurred after 12 h of shaking in a pH = 5 aqueous solution with 2 mg mL^-1 NH₂-ZIF-90. The adsorption kinetics conformed to a pseudo-second-order model, and the equilibrium data fit the Freundlich isotherm model well. Finally, NH₂-ZIF-90 was successfully used in lake water and tap water samples for Au(III) adsorption, with recovery rates ranging from 81.0% to 93.3%. This study presents a novel approach for addressing Au(III) adsorption challenges.