EDTA functionalized magnetic nanoparticle sorbents for cadmium and lead contaminated water treatment

Cadmium (Cd(2+)) and lead (Pb(2+)) are toxic to human beings and other organisms, and the U.S. Environmental Protection Agency (EPA) has classified both as probable human carcinogens. In this study, a regenerable magnetic ligand particle (Mag-Ligand) which includes a metal-binding organic ligand (EDTA) attached to an iron oxide nanoparticle was developed for rapid removal of Cd(2+) and Pb(2+) as well as other metals from contaminated water. Mag-Ligand showed fast removal ability for both Cd(2+) (<2 h) and Pb(2+) (<15 min) with relatively high sorption capacity (79.4 and 100.2 mg/g for Cd(2+) and Pb(2+), respectively). The removal performance of Mag-Ligand was high across a wide pH range (3-10) as well as in the presence of competitive metal ions (Ca(2+) and Mg(2+)). In addition, Mag-Ligands can be easily regenerated (washed by 1% HCl) and reused several cycles with high sorption capacity. This study indicated that Mag-Ligand is a reusable sorbent for rapid, convenient, and efficient removal of Cd(2+) and Pb(2+) from contaminated aquatic systems.