Interactions of chlorine with tropical aquatic fulvic acids and formation of intermediates observed by fluorescence spectroscopy

Author(s)

Eduarda R. Carvalho ^[1] ; Ladislau Martin-Neto ^[2] ; Débora M.B.P. Milori ^[3] ; Julio C. Rocha ^[4] ; André H. Rosa ^[5]

Affiliation

^[1] Brasil. Ministério da Agricultura, Pecuária e Abastecimento. Embrapa Instrumentação Agropecuária - Brasil

^[2] Embrapa Instrumentação Agropecuária - Brasil

^[3] Embrapa Instrumentação Agropecuária - Brasil

^[4] Universidade Estadual Paulista. Instituto de Química - Brasil

^[5] Universidade Estadual Paulista. Departamento de Engenharia Ambiental - Brasil

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 15, n. 3, p. 421-426, 2004-06-00.
• Field of knowledge: Physical Sciences and Mathematics - Chemistry

Abstract

The interactions of tropical aquatic fulvic acids (AFA) with chlorine and formation of trihalomethanes were characterized by fluorescence spectroscopy. The aquatic humic substances (AHS) were isolated from a dark-brown stream (located in a environmental protection area near Cubatão city in São Paulo State, Brazil) by means of the collector XAD 8 according the procedure recommended by the International Humic Substances Society. The photoluminescence measurements were made by using a Perkin Elmer spectrometer; AHS, aquatic humic acids (AHA) and AFA samples were assayed. The interactions of AFA and chlorine were characterized by using different reaction times (1, 24, 48, 72 and 168 h) and chlorine concentrations (2.5, 5.0, 10.0 and 20.0 mg L-1). The relative fluorescence intensity for AFA was significantly decreased with the increasing of chlorine concentration and reaction time. The reduction of fluorescence intensity in the region of longer wavelength was interpreted as an indicative of interaction between condensed aromatic groups of AFA and chlorine. (AU)