<title>Study of cresol phototransformations in neutral and acidic medium</title>

Abstract

It is well known that pH value and excitation energy have a directly impact on photolysis rate of phenols under Hg-lamp irradiation and oxidation process. The purpose of the current study is the research of o-cresol and para-cresol photolysis in acidic medium under various spontaneous radiation sources irradiation. Photochemical degradation was carried out through a high pressure mercury lamp OKH-1 1M, and also with a new capacitive discharge excilamps on working molecules KrC1* (2v222 nm) and XeBr* (X'-283nm). Exposure time was varied from 1 to 40 minutes that corresponds radiation doses from 0.5 to 20 J/cm2. A comparison between phototransformations under different light excitation shows that cresol aqueous solutions acidation leads to increase of phototransformations efficiency. It has been found that both in neutral, and in acidic medium the photodecomposition of cresols is carried out more effectively under KrC1-excilamp irradiation.

Luminescence investigations of the degradation of 2-methylphenol and 4-methylphenol in water

“…The parameters and choice of the lamps are discussed elsewhere [3]. The time of irradiation of a test solution was 1-60 min, and the energy absorbed per unit volume of the solution within this time was 1-5 J/cm 3 .…”

“…For the last twenty years the sewage treatment technology has developed toward the use of combined salvage methods, including bioprocessing and physicochemical methods. Highly efficient photodegradation of phenol and of some its substituents exposed to the radiation of KrCl and XeBr excilamps was noted earlier [1][2][3]. In this connection, of particular importance are the problems related to the effect of the radiation of new narrow-band uv sources on the biodegradability and toxicity of water solutions of organic compounds.…”

Investigation of the toxicity of aqueous media after high-energy exposure by the spectralluminescent methods

“…Sufficiently extensive experimental data on photodestruction of organic substances excited by UV-radiation are now available (see [1][2][3][4]) supported by the results of quantum-chemical calculations [5,6] and experiments on laser flash-photolysis [7,8] that allow the physical nature of this process to be elucidated. The luminescent and chromatographic methods of analysis of photodegradation products of organic compound in aqueous media have been developed [9].…”