چكيده به لاتين
With the increasing impact of human activities, various synthetic organic chemicals have been released through wastewater. Considering the harmful effects of these pollutants to environment and health, their removal from the water and wastewater resources using appropriate processes is very essential. Various methods have been developed to remove organic pollutants from the water and wastewater environment, and chemical processes have generally received more attention due to the high rate of reactions. Among the various chemical processes, the advanced photochemical oxidation process using UV light and hydrogen peroxide (H2O2) is a well-known technology for water and wastewater treatment. The main advantage of using UV/H2O2 systems is that UV radiation can simultaneously help oxidize and disinfect organic pollutants. In this research, a photoreactor with a 16 W low pressure mercury lamp was made so that a helical current is formed inside it. Using the made photoreactor, synergic of this fluid phenomenon and the UV/H2O2 process, the removal of organic contaminants methyl orange was investigated. By response surface methodology, the optimal values of the factors affecting removing this contaminant (discharge, initial contaminant concentration, and hydrogen peroxide concentration) were calculated. Finally, a comparison between the pollutant removal efficiency in two modes of reactor without helical blade and with a helical blade was made with a comparison of the quasi-first-order kinetic constant, absorption spectrum, and percentage of TOC removed. The results showed that the optimal values of the parameters to achieve 99.5% removal of methyl orange was happened in the flow of 22.2 liters per minute, the initial concentration of the pollutant 30.5 mg/l, and the concentration of hydrogen peroxide 1722.7 mg/l. Validation of the predicted software's optimal conditions showed a perfect agreement between the experimental data and the model's optimal condition data. Using MSE, RMSE, MAE, R, and R2 evaluations, the quasi-first-order kinetic model, is best suited for the degradation of methyl orange dye contaminants. Finally, it was observed that the quasi-first-order kinetic constant is 0.2442 min-1 in the blade state and 0.1487 min-1 in the bladeless state, with the absorption spectrum's peak at 20 minutes. The absorption spectrum peak was higher in the reactor without the helical. Finally, the TOC removal percentage of the reactor with the helical was 92.6% and without the helical 89.43%, which shows better performance of the helical reactor's in UV/H2O2 process of methyl orange removal.
