The elimination of organic pollutants from industrial wastewaters is an important goal in modern chemical industry. Biogical, chemical, physicochemical attacks can be applied, the efficiency of each of them depending on the nature of the polluting substrate and on the specific effluent composition. Biological attacks, most commonly adopted, may be hindered by the presence of microtoxic substances in the effluent. Electrochemical or photochemical mineralization, or “incineration”, may be of interest in cases where the direct application of the biological attack is not ef-fective because of the presence of bio-refractory species, or of high COD values. The possibility to operate at high anodic potentials, allows the production of very reactive intermediates like hydroxyl-, chloro-, oxychloro radicals at the electrode surface. This makes the electrochemical attack a very effective one, also in the case of relatively stable organic substrates. Its application in industrial pollution abatement is, however, interesting only in cases where the faradaic yield of the electrochemical incineration reaction is high. The yield parameter, in turn, is controlled by the nature of the electrode material which conditions the mechanism of the process. In this frame, the attempt of optimization of the faradaic yield requires a thorough analytical approach, in order to identify the intermediates of the mineralization process and the dependence on electrolysis time of their concentration. In the present work the electrochemical incineration of a test substrate, like glucose, has been studied at different electrodes. The many variables controlling the process have prompted an extended application of planar chromatography. Its methodological features allowed the identification and dosage of reaction intermediates in large numbers of parallel runs. The quali-quantitative screening carried out by planar chromatography allowed further insight by other chromatographic techniques and mass spectrometry.
Analytical aspects in studies of electrochemical incineration of organic pollutants
FERRO, Sergio;LODI, Gaetano;DE BATTISTI, Achille
1998
Abstract
The elimination of organic pollutants from industrial wastewaters is an important goal in modern chemical industry. Biogical, chemical, physicochemical attacks can be applied, the efficiency of each of them depending on the nature of the polluting substrate and on the specific effluent composition. Biological attacks, most commonly adopted, may be hindered by the presence of microtoxic substances in the effluent. Electrochemical or photochemical mineralization, or “incineration”, may be of interest in cases where the direct application of the biological attack is not ef-fective because of the presence of bio-refractory species, or of high COD values. The possibility to operate at high anodic potentials, allows the production of very reactive intermediates like hydroxyl-, chloro-, oxychloro radicals at the electrode surface. This makes the electrochemical attack a very effective one, also in the case of relatively stable organic substrates. Its application in industrial pollution abatement is, however, interesting only in cases where the faradaic yield of the electrochemical incineration reaction is high. The yield parameter, in turn, is controlled by the nature of the electrode material which conditions the mechanism of the process. In this frame, the attempt of optimization of the faradaic yield requires a thorough analytical approach, in order to identify the intermediates of the mineralization process and the dependence on electrolysis time of their concentration. In the present work the electrochemical incineration of a test substrate, like glucose, has been studied at different electrodes. The many variables controlling the process have prompted an extended application of planar chromatography. Its methodological features allowed the identification and dosage of reaction intermediates in large numbers of parallel runs. The quali-quantitative screening carried out by planar chromatography allowed further insight by other chromatographic techniques and mass spectrometry.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
