title: Manganese doping of magnetic iron oxide nanoparticles: tailoring surface reactivity for a regenerable heavy metal sorbent.
abstract: A method for tuning the analyte affinity of magnetic, inorganic nanostructured sorbents for heavy metal contaminants is described. The manganese-doped iron oxide nanoparticle sorbents have a remarkably high affinity compared to the precursor material. Sorbent affinity can be tuned toward an analyte of interest simply by adjustment of the dopant quantity. The results show that following the Mn doping process there is a large increase in affinity and capacity for heavy metals (i.e., Co, Ni, Zn, As, Ag, Cd, Hg, and Tl). Capacity measurements were carried out for the removal of cadmium from river water and showed significantly higher loading than the relevant commercial sorbents tested for comparison. The reduction in Cd concentration from 100 ppb spiked river water to 1 ppb (less than the EPA drinking water limit of 5 ppb for Cd) was achieved following treatment with the Mn-doped iron oxide nanoparticles. The Mn-doped iron oxide nanoparticles were able to load ~1 ppm of Cd followed by complete stripping and recovery of the Cd with a mild acid wash. The Cd loading and stripping is shown to be consistent through multiple cycles with no loss of sorbent performance.
authors.affiliation: Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Warner
authors.forename: Wilaiwan
authors.initials: W
authors.lastname: Chouyyok
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Mackie
authors.forename: Doinita
authors.initials: D
authors.lastname: Neiner
authors.forename: Laxmikant V
authors.initials: LV
authors.lastname: Saraf
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Droubay
authors.forename: Marvin G
authors.initials: MG
authors.lastname: Warner
authors.forename: R Shane
authors.initials: RS
authors.lastname: Addleman
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D019216:Metals, Heavy / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods
chemical_list: D005290:Ferric Compounds; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; C000499:ferric oxide; D008345:Manganese