Transformation of Phenol and Diatomic Phenols in Surface Water Under the Impact of Natural Physical and Chemical Factors

Abstract

Introduction. Phenol, as well as diatomic phenols, are among the most common and priority organic pollutants of the environment. Getting into the water with sewage in real conditions of pollution, under the influence of natural physicochemical factors, phenols, as highly reactive compounds, undergo a transformation, as a result of which new, sometimes more toxic compounds may be formed. Purpose of the study is to investigate the transformation processes under the impact of the natural physicochemical factors of phenol, hydroquinone, pyrocatechin, and resorcinol in surface water. Material and methods. The processes of transformation of phenol and diatomic phenols were studied by the methods of spectrophotometry and luminescence spectroscopy. Absorption spectra were recorded with a UV-1800 spectrophotometer (Shimadzu, Japan), and fluorescence spectra were recorded on a CM2203 spectrofluorometer (Solar CJSC, Belarus). The degradation of phenols to CO2 and H2O (mineralization) at room temperature in natural samples was determined using a TOC-VCHP total carbon analyzer (Shimadzu, Japan). Results. The decrease in phenol concentration in river water was subject to linear dependence. The transformation kinetics of resorcinol corresponded to a sequential reaction. The processes of transformation of hydroquinone and pyrocatechin were dominated by chemical oxidation processes. Hydroquinone completely transformed within 24 hours. The degree of conversion of pyrocatechol 87.5% was achieved in 3 days and did not change during the month. During the month, the mineralization of phenol amounted to 90%, hydroquinone, and pyrocatechol - 55% and 45%, respectively. The complete transformation of resorcinol occurred in 7 days. A compound having a bright fluorescence and constituting a product of resorcinol polycondensation, whose concentration increased during the whole experiment, was formed. The degree of mineralization of resorcinol was 93%. Conclusion. The transformation of phenol, hydroquinone, pyrocatechin, and resorcinol in the surface water is caused by the processes of natural chemical and biochemical oxidation and depends on the chemical composition and concentration of presented impurities.