In-Situ Fixation of All-Inorganic Mo–Fe–S Clusters for the Highly Selective Removal of Lead(II)

The selective adsorption by suitable substrate materials is considered one of the most economical methods. In this work, an all-inorganic bimetallic Mo–Fe–S cluster is facilely achieved through in situ chemical fixation of tetrathiomolybdate (TTM) on Fe 3 O 4 nanoparticles (NPs) at room temperature (donated as FeMoS NPs). The bimetallic building blocks on the obtained FeMoS NPs possess a monovacancy species of sulfur, endowing FeMoS NPs with a selectivity order of Zn 2+, Mn 2+, Ni 2+ < Cd 2+ ≪ Cu 2+ < Pb 2+ for metal-ion adsorption, a novel application for the Mo–Fe–S clusters. Particularly, with the highest selectivity for Pb 2+ ( K d ≈ 10 7 ), which is about 3 × 10 3 –1 × 10 6 times higher than those for other ions and has exceeded that of a series of outstanding sorbents reported for Pb 2+, FeMoS NPs can efficiently reduce the concentration of Pb 2+ from ∼10 ppm to an extremely low level of ∼1 ppb. This facile and rational fabrication of the Mo–Fe–S cluster with Fe 3 O 4 represents a feasible approach to cheaply develop novel and efficient materials for the selective removal of lead(II).