Study of aquatic fulvic acids isolated from french surface waters - Isolation procedure, characterization, and reactivity with chlorine
Numerous procedure for the isolation of aquatic humic substances are described in literature. The first part of this study presents the extraction of fulvic and humic acids from eleven French surface waters, using XAD 8 macroreticular resin as developed by TRURMAN and MALCOLM (1981). The results are discussed in terms of extraction yield and fulvic acid/humic acid mass ratio. The second part of the paper presents some structural parameters of the extracted fulvic acids such as elemental analysis, UV-absorbance, carboxyle-function content and in some cases of fulvic acids, infrared spectrum and apparent molecular weight investigated by ultra filtration. The third part of the work concerns the study of fulvic acids chlorination. Firstly, the gas chromatography - mass spectrometry analysis of one chlorinated fulvic acid allowed us to identify some chlorination by-products and especially chloroform, dichloro-acetic and trichloroacetic acids and some other chlorinated aliphatic acids. Secondly, the chlorine reactivity potentials of each fulvic acids were determined and results are discussed in terms of chlorine consumption, chloroform and total organohalides formation potentials. Some relationships are established between the chlorine reactivity potentials and UV-absorbance of the extracted fulvic acids.