КАВІТАЦІЯ У КОМБІНОВАНИХ ТЕХНОЛОГІЯХ ОЧИЩЕННЯ СТІЧНИХ ВОД ВІД ТОЛУЕНУ

Abstract

The use of acoustic and hydrodynamic cavitation and their combinations with other methods (reagent treatment – hydrogen peroxide, Fenton reagent, ozone, etc.) for wastewater treatment from dispersed solids and organic compounds is analyzed. The feasibility of combining cavitation with rea-gent treatment to increase the degree of pollutant degradation has been demonstrated. A characteristics of the spectroscopy method in ultraviolet and visible spectral ranges is given to determine the concentration of toluene in wastewater imitation. The dependences of toluene concentration and the reaction system temperature on the duration of cavitation treatment at different values of the specific power of ultrasonic radiation, the pressure at the entrance to hydrodynamic cavitator, different reagent modes are presented. The degree of toluene degradation and the rate constant of this process for different parameters of cavitation processing are calculated. It is found that an increase in the specific power of ultrasonic radiation from 53.3 to 83.3 W/dm3 has caused a decrease in the degree of toluene degradation by 11.2 % (from 82.5 to 71.3 %), and the rate constant by 2.5 times (from 5.6·10-4 to 2.2·10-4 s-1), which is explained by two factors: the formation of Babstones and the change in the structure of the fluid according to Frenkel's kinetic theory. It is established that the use of combined technology (acoustic cavitation + hydrogen peroxide) allows to increase the rate of toluene degradation from 82.5 to 84 % and the rate constant by 26.8 % (from 5.6·10-4 to 7.1·10-4 s-1). It is determined that the combination of hydrodynamic cavitation and reagent treatment (hydrogen peroxide) allows to increase the rate of toluene degradation by 2.5 % (from 95.8 to 98.3 %). By comparing the rate constants of toluene degradation and the degradation rates for combined technologies (acoustic cavitation + H2O2; hydrodynamic cavitation + H2O2), it is found that hydrodynamic cavitation is much more efficient than acoustic one.