文摘
We have shown that superparamagnetic iron oxide(Fe3O4) nanoparticles with a surface functionalization ofdimercaptosuccinic acid (DMSA) are an effective sorbentmaterial for toxic soft metals such as Hg, Ag, Pb, Cd,and Tl, which effectively bind to the DMSA ligands andfor As, which binds to the iron oxide lattices. The nanoparticlesare highly dispersible and stable in solutions, have alarge surface area (114 m2/g), and have a high functionalgroup content (1.8 mmol thiols/g). They are attracted toa magnetic field and can be separated from solution withina minute with a 1.2 T magnet. The chemical affinity,capacity, kinetics, and stability of the magnetic nanoparticleswere compared to those of conventional resin basedsorbents (GT-73), activated carbon, and nanoporous silica(SAMMS) of similar surface chemistries in river water,groundwater, seawater, and human blood and plasma. DMSA-Fe3O4 had a capacity of 227 mg of Hg/g, a 30-fold largervalue than GT-73. The nanoparticles removed 99 wt % of 1mg/L Pb within a minute, while it took over 10 and 120min for Chelex-100 and GT-73 to remove 96% of Pb.