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Abstract

Reactions between natural organic substances or humic substances (HS) and various metal ions are studied by spectrofluorimetric techniques using a pulsed laser to excite the sample at 308 nm. Eu and Tb are used as probe elements for their fluorescent properties. Using a process of titration in balanced conditions, the maximum bonding capacities and compounding constants of the HS are determined with diamagnetic elements such as Cr(III) and Al(III). The kinetics of reaction are studied in systems with several components in the presence of anthropogenetic chelating agents (Ln/HS/EDTA/Ca). The speed of dissociation of the LnHS compound, by exchanging bonds with EDTA, drops considerably in the presence of Ca and with a reduction in the total Ln concentration. The formation of fluorescent LnHS types may be used to investigate the compounding capacities of natural water in situ. This is verified using samples of underground water to which small volumes of a solution of Ln(III) ions are added directly.

Additional information

Authors: BIDOGLIO G, JRC Ispra (IT);OMENETTO N, JRC Ispra (IT);HALTIER E, JRC Ispra (IT);O'GORMAN M, JRC Ispra (IT)
Bibliographic Reference: Paper presented: Secondo Convegno Nazionale di Chimica Fisica Ambientale, Siena (IT), Nov. 8-12, 1990
Availability: Available from (1) as Paper IT 35844 ORA
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