PHOTOCATALYTIC TREATMENT OF WATERS, POLLUTED WITH PHENOLS

The analysis of the environmental and human health threats imposed by phenols was conducted to show the need for further improvement of methods of their destruction. Being toxic in their initial composition and precursor to toxic metabolites in human body, phenols should be controlled in natural water and waste waters. They are listed as priority pollutants in most national regulation around the world and are the initial compounds for the formation of persistent organic pollutants in the environment, polluted with other active radicals. A variety of physical and chemical methods were offered for the destructive or non-destructive removal of phenols and their derivatives from water. The comparative study of possible methods, described in research papers, was conducted in terms of their efficiency and complexity to define benefits and drawbacks. The analysis showed the need for development of low energy consuming method, which needs minimal equipment and can be run under industrial condition for phenol contaminated wastewaters. Among the possible methods which meet the mentioned criteria photocatalytic destruction of phenols was showed to be perspective. A series of experiments was conducted using a range of water solution of phenol and different dosage of catalysts. The catalysts used in experiments were made of 6 modification of titanium oxide and bismuth ferrite. The initial and residual concentration of phenol was controlled by the means of high-performance liquid chromatography. The duration of the exposure and the type of light were other independent variables. The results of the whole sequence of experiments demonstrated higher efficiency of rutile under visible light and one hour of exposure. The tested photocatalytic system is simple and therefore technically and economically feasible.