Fluorescence quenching and aluminum adsorption to organic substances
- McMaster Univ., Hamilton, Ontario (Canada)
Fluorescent measurements of Al-modified natural organic matter (NOM) were used to better determine site-specific aluminum binding sites. Excitation-emission surfaces were used to characterize fluorescent groups within NOM; further, the kinetics of the reaction were followed by observing emission signal change over time. Calibration experiments were carried out on salicylic acid and the more complex Armadale and Suwannee River reference fulvic acids. Salicylic acid showed one fluorophore but the fulvic acids contain at least two distinct fluorophores that are modified with aluminum addition. Existing equilibrium speciation models for salicylic acid are correlated to the changes in fluorescence with added Al at fixed pH and ionic strength. Al speciation can be modelled by a modified Stern-Volmer or Ryan-Weber equation. The kinetics of the salicylate reaction suggest two reaction modes, an initial quick reaction (seconds) followed by a slower second reaction (minutes).
- OSTI ID:
- 370506
- Report Number(s):
- CONF-960376--
- Country of Publication:
- United States
- Language:
- English
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