title: Sorption of noble-metal ions on silica with chemically bonded nitrogen-containing ligands.
abstract: A study has been made of the sorption of Ir(IV), Rh(III), Pt(IV), Ru(IV), Os(VIII), Pd(II) and Au(III) from aqueous solutions by silica chemically modified with nitrogen-containing organic ligands, as a function of hydrochloric acid concentration, time of contact, concentration of the element and the ionic strength. Sorption of noble-metal ions at pH > 1 on a sorbent containing monoamine groups seems to be due to a complexation mechanism, and to an anion-exchange mechanism at pH < 1. With aminopropyl-silica 1000-fold concentration of Ir(IV) and Rh(III) from their 10(-8)-10(-7)M solutions was achieved and these metals were subsequently determined on the sorbent surface by X-ray fluorescence. Detection limits were 10-20 ng/ml. There was no interference from 1000-fold quantities of non-ferrous metal ions and Fe(III). With the sorbent containing bonded diethylenetriamine groups, 1000-fold concentration of Au(III) was achieved, and it was then determined on the sorbent surface by an atomic-emission method. Conditions for desorption of Au(III) with pyridine and potassium thiocyanate were developed.
authors.affiliation: Department of Chemistry, M.V. Lomonosov State University, Moscow 119899, U.S.S.R.
authors.forename: T I
authors.initials: TI
authors.lastname: Tikhomirova
authors.forename: V I
authors.initials: VI
authors.lastname: Fadeeva
authors.forename: G V
authors.initials: GV
authors.lastname: Kudryavtsev
authors.forename: P N
authors.initials: PN
authors.lastname: Nesterenko
authors.forename: V M
authors.initials: VM
authors.lastname: Ivanov
authors.forename: A T
authors.initials: AT
authors.lastname: Savitchev
authors.forename: N S
authors.initials: NS
authors.lastname: Smirnova