Fluorescence analysis of photoinduced degradation of ecotoxicants in the presence of humic acids

Abstract

The photolysis of humic acids and phenols in water containing humic acids was investigated. Humic acids extracted from peat (Vasuygan Bog, Tomsk Region, Russian Federation) induce the phototransformation of 4‐chlorophenol at 365 and 222 nm. Humic acids were characterized by UV‐, fluorescence‐, IR‐ and EPR‐spectroscopy and laser‐induced fluorescence. The influence of humic acids on the phototransformation of phenols in different irradiation conditions was investigated. Comparison of the data on mercury lamp irradiation showed that the most effective phenols degradation was observed under exposure to KrCl* exilamp light (λ = 222 nm) in the presence of humic acids. Copyright © 2005 John Wiley & Sons, Ltd.

Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments

“…Subsequently, the fate of persistent toxic substances (PTS) in natural waters could be influenced significantly by HAs since the photochemically mediated processes are important in the transport and transformation of most PTS. Numerous studies have demonstrated that the effects of humic materials on the photodegradation of pollutants were complex, and HAs acted either as photosensitizers [5][6][7] or as inhibitors (light attenuating) [8,9] depending on their different functional groups [10,11].…”

Quenching of fluorescence of phenolic compounds and modified humic acids by cadmium ions

“…The properties of humic substances and their capability to enter into various donor-acceptor interactions are determined by the presence of a large number of carboxyl and hydroxyl groups as prevailing peripheral substitutes in the aromatic nucleus (1)(2)(3)(4). The properties of humic substances and their capability to enter into various donor-acceptor interactions are determined by the presence of a large number of carboxyl and hydroxyl groups as prevailing peripheral substitutes in the aromatic nucleus (1)(2)(3)(4).…”

“…A study of fluorescence of polyatomic molecules is of interest for the estimation of intermolecular interactions and the degree of complexation of humic acids (HAs) with pollutants. The properties of humic substances and their capability to enter into various donor-acceptor interactions are determined by the presence of a large number of carboxyl and hydroxyl groups as prevailing peripheral substitutes in the aromatic nucleus (1)(2)(3)(4). Humic acids are capable of bonding toxic organic compounds such as phenols and polycyclic aromatic hydrocarbons and ions of heavy metals (5).…”

Fluorescence and bioluminescence analysis of sequential UV‐biological degradation of p‐cresol in water

“…In coastal marine and freshwater systems, exposure of dissolved organic matter to UV radiation has been shown to result in subsequent because they are resistant to microbial degradation and have only weak absorbance above 300 nm. We have studied the transformation of humic acids by UV radiation previously (11,12). The humic acids concentrate was dissolved in phosphate buffer.…”

“…This is not a universal response: exposure of surface water DOM might also lead to reduced bacterial activity due to photoproduction of hydroxyl radical and other reactive species (7,8). The effects of individual toxic compounds on microbiological degradation of initial pollutants and their photoproducts has been studied for phenol, some pesticides and PAH (9)(10)(11). To date, the sequential UV-biological degradation of cresols has not been studied.…”