High-Performance, Superparamagnetic, Nanoparticle-Based Heavy Metal Sorbents for Removal of Contaminants from Natural Waters

We describe the synthesis and characterization of high‐performance, superparamagnetic, iron oxide nanoparticle‐based, heavy metal sorbents, which demonstrate excellent affinity for the separation of heavy metals in contaminated water systems (i.e., spiked Columbia River water). The magnetic nanoparticle sorbents were prepared from an easy‐to‐synthesize iron oxide precursor, followed by a simple, one‐step ligand exchange reaction to introduce an affinity ligand to the nanoparticle surface that is specific to a heavy metal or class of heavy metal contaminants. The engineered magnetic nanoparticle sorbents have inherently high active surface areas, allowing for increased binding capacities. To demonstrate the performance of the nanoparticle sorbents, river water was spiked with specific metals and exposed to low concentrations of the functionalized nanoparticles. In almost all cases, the nanoparticles were found to be superior to commercially available sorbent materials as well as the unfunctionalized iron oxide nanoparticles. Superparamagnetic iron man: The synthesis and characterization of superparamagnetic, iron oxide nanoparticle‐based heavy metal sorbents with various surface chemistries, which demonstrate excellent affinity for the separation of heavy metals in contaminated natural water systems is described. Our method has the unique advantage that the analyte reactivity is incorporated into the nanoparticle ligand shell without altering the desirable properties of the starting nanoparticle.