Transition metal doped ZIF-8 for the detection of the heavy metal Hg(II)

Abstract

The effects of heavy metals such as Hg(II) and Pb(II) on the human body are profound. Moreover, they pose significant concerns due to industrial development. Thus, the rapid and stable detection of heavy metal ions and related chemicals has emerged as an urgent issue. The application of Differential Pulse Stripping Voltammetry (DPSV) facilitated accurate and rapid detection of Hg²⁺ utilizing MOF materials and ZIF-8 as detection agents. Pure ZIF-8 served as the substrate material. Copper or nickel ions were individually introduced into the substrate material. This process resulted in the formation of bimetallic MOF materials. These materials were designated as CuZn and NiZn, respectively. Transition metal-doped materials were used to modify the glassy carbon electrode (GCE), resulting in a substantial enhancement in the detection performance of Hg²⁺. The CuZn/GCE configuration demonstrated the most significant enhancement. When compared to a GCE modified with pure ZIF-8, both sensitivity and the detection limit for free Hg²⁺ in the environment experienced increases of 450% and 64%, respectively. Stability and repeatability tests were conducted on the CuZn-modified GCE. Results indicated that the electrode proved to be very stable and showed strong selectivity in the presence of interfering ions. The sensor modified with CuZn shows promising potential for monitoring trace Hg²⁺ levels.