Microwave-assisted synthesis of Cu2O activated metal organic framework for selective adsorption of Au(III)

The disposal of gold-containing wastewater not only causes a waste of resources but also triggers major health issues. Herein, Cu2O functionalized ZIF-8 (CZF8-MW) was successfully synthesized by microwave-assisted method to adsorb gold (Au) ions in the water environment. The performance and mechanism of Au(III) adsorbed on CZF8-MW were systematically studied. The results reveal that CZF8-MW exhibits excellent adsorption capacity and a stronger affinity for Au(III) compared with pure Cu2O. The boosted adsorption mechanism of Au(III) can be ascribed to the electrostatic attraction between CZF8-MW and Au(III) in acidic conditions (pH ​= ​3.0) and the reduction of Au(III) to Au(I) and Au(0) by Cu2O, prompting that the adsorption capacity of CZF8-MW is 1300 ​mg ​g−1 at 318 ​K. Besides, CZF8-MW holds superior selectivity for Au(III) in the presence of competing ions and shows outstanding reusability after five cycles. These results indicate that CZF8-MW possesses a great potential application for the adsorption of Au(III) from wastewater.