DETERMINATION OF OPTIMAL PARAMETERS OF PHOTOCATALYTIC DESTRUCTION OF METHYLENE BLUE IN THE PRESENCE OF MAGNETITE

Abstract

The use of mathematical modelling for the development of new technologies for wastewater treatment is very The use of mathematical modelling for the development of new technologies for wastewater treatment is very important because it allows to reduce the number of experiments, to determine the optimal process conditions, to build a mathematical model. Multifactor dependencies, which, for example, are obtained using experimental planning methods, are powerful statistical tools that allow to determine the total impact of the studied variables, which can be estimated simultaneously, to statistically process the results to be used, to optimize using mathematical models to obtain the best experimental conditions for the purification process. To assess the influence of selected factors, the method of central compositional planning of the experiment was used. The effect of parameters such as photocatalyst concentration (x1), H2O2 volume (x2) and UV treatment time (x3) on the degradation of methylene blue (MB) was determined. The presented results show that magnetite is an effective catalyst for the decomposition of MB under the action of UV radiation. Is established that most effects are statistically significant for the response function. High values of the coefficients at x3, x1, x2 indicate that they are the most influential in the process of photocatalytic destruction. The coefficient at x3 not only has the highest value of all effects, but is also about 2 times greater than the coefficient at x1. The coefficients corresponding to the interactions x1x2 (1.32) and x1x3 (5.24) are represented by values that are 5,84 and 1.5 times less than the coefficient at x3. The value of the of determination coefficient (R2) is approximately 0.998, which confirms the adequacy of the quadratic model, which represents the relationship between independent factors and the response function. High values of coefficients in linear terms (x2, x3) in comparison with other coefficients mean that they are the most influential in the equation. It was found that increasing the processing time led to an increase in the degree of degradation of MB The effect of the concentration of hydrogen peroxide and catalyst is extreme. The significance of the factors varies as follows: ttreat> mkat> Vn2o2. In addition, analysis of variance showed consistency between experimental data and theoretically determined, i.e. the obtained mathematical model is adequate.