Degradation of chlorinated hydrocarbons by UV/H2O2: The application of experimental design and kinetic modeling approach

The aim of the study was to develop a detail mathematical model describing the degradation of chlorinated hydrocarbon pollutants in water by UV/H2O2 process. As a model representative of chlorinated hydrocarbons para-chlorophenol (p-CP) was chosen. A degradation mechanism of parent pollutant to its aromatic and aliphatic by-products, as well as the mineralization of simulated wastewater, was included in the model. The optimal values of operating parameters of UV/H2O2 process influencing the treatment efficiency were established by the means of the two-factor three-level Box–Behnken experimental design combining with response surface modeling (RSM) and quadratic programming. The results of such experimental design using different statistical tools showed that pH 6.8 and pollutant/oxidant ratio 1:199 maximize the performance of oxidative treatment system. The model was tested to evaluate accuracy in predicting system behavior at different process conditions and pollutant concentrations. Rather high accuracy of developed model was demonstrated at all tested conditions. Good accordance of the data predicted by model and the empirically obtained data was confirmed by calculated standard deviation (SD) for each experimentally monitored parameter. Hence, the developed mathematical model describing the kinetic of p-CP degradation by UV/H2O2 can be characterized as interpretable, transparent and accurate, and therefore can be used as a tool for maximizing efficiency of wastewater treatment process.