Revista Egitania Sciencia - Volume 2 | ARTICLE

Title: FRACCIONATION OF THE DISSOLVED ORGANIC MATTER PRESENT IN THE WATER OF THE CALDEIRÃO DAM

Author: Pedro Rodrigues (prodrigues@ipg.pt) e Joaquim Silva

Publication: Revista Egitania Sciencia - Volume 2

Abstract:
The objective of this work is extract and characterized the DOM (dissolved organic matter) fractions present in the water of Caldeirão dam (Guarda, Portugal), especially in colloid, hydrophobic and transphilic components. The DOM was concentrated by a reverse osmosis system and the fractions were isolated by a dialysis membrane and adsorption to XAD-4 and XAD-8 resin. Three fractions of DOM, colloid, hydrophobic, and transphilic, were isolated and characterized through UV-Vis espectroscopy, molecular fluorescence and FT-IR. The hydrophilic fraction was characterized by molecular fluorescence. The DOM concentration was estimated at 82 mg per 100 L of water and the percentage, in mass, for the four fractions was 37, 25, 16 and 22%, respectively. The colloidal fraction has unique structural characteristics and apparently is originated from bacteria wall cells. This fraction is characterized by the absence of no aromatic structures, a relatively high molecular weight and contains N-acetylglucosamines residuals. The other three DOM fractions show similarities and there is a hydrophobic>transphilic>hydrophilic trend for the following properties: molecular weight, quantity of condensed aromatic structures and molecular complexity.

Keywords: DOM fractionation and characterization; colloids; hydrophobic fraction; transphilic fraction; hydrophilic fraction




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