SEPECTROPHOMETRIC DETERMINATION OF SILVER AFTER PRECONCENTRATION OF ELEMENTAL SILVER ON ACTIVATED CARBON

A simple,accurate,sensitive and selective method was described for rapid determination of ultra-trace quantities of silver.Ag(Ⅰ) was collected on activated carbon(AC) after reduction to elemental Ag by L-ascorbic acid at pH 1.0,However,familiar metal cations,such as Cu(Ⅱ)、Fe(III)、Co(Ⅱ)、Ni(Ⅱ)、Pb(Ⅱ)、Zn(Ⅱ)、Mn(Ⅱ)、Al(Ⅲ)、Bi(Ⅲ),Sb(Ⅲ) were not adsorbed under this condition.The collected silver was oxidized by Potassium peroxydisulfate,was exchanged by Mg2+ in sulfuric acid media and was determined by sepectrophometer.The Enrichment of Ag(Ⅰ) was 93.2～97.1% in the concentration of 8～50μg/L.This method was used to the determination of Ag(Ⅰ) in natural water with satisfactory results.The adsorption behavior of silver on activated carbon was studied.It showed that ion-exchange of Ag+ and Mg2+ was existed on the surface of oxidized activated carbon.