حانيه ساجدي

Surfactants, as one of the organic compounds, are present in the wastewater of many detergent an‎d hygiene industries, as well as in household wastewater. The presence of these compounds in aquatic environments causes environmental pollution an‎d endangers the health of aquatic organisms. Therefore, the removal of these compounds from wastewater has always been one of the important an‎d prominent issues in the field of industry an‎d environment. Among them, the surfactant sodium dodecylbenzene sulfonate, which is known as one of the anionic surfactants, is found in very large quantities in astewater. Unfortunately, conventional treatment methods for removing this compound have not been able to achieve effective results an‎d continue to face numerous challenges an‎d problems.In this study, a combination of advanced oxidation methods, which are among the most modern techniques for removing resistant an‎d stable compounds, has been used to eliminate this pollutant. The hybrid system in question consists of hydrodynamic cavitation, ultraviolet radiation, an‎d the use of oxidants such as hydrogen peroxide an‎d persulfate. The experiments were conducted under the conditions of an initial concentration of 10 mg.L-1 of the surfactant SDBS, a wastewater volume of 4 liters, a pressure of 3 bar, a temperature of 30±2◦, an‎d a duration of 40 minutes. In order to investigate the parameters affecting the process, an experimental design was conducted using the Box-Behnken method an‎d the parameters of UV radiation power intensity (0-32 w), hydrogen peroxide concentration (100-300 mg.L-1), an‎d sodium persulfate concentration (100-300 mg.L-1). Based on RSM analysis, the optimal conditions included concentrations of 210 mg.L-1 an‎d 182 mg.L-1 for H₂O₂ an‎d PS, respectively, an‎d a UV power of 16 ws, under which the pollutant degradation was reported to be 98.2% an‎d the rate constant was 100.5×10-3min-1. Comparison of the processes in terms of energy consumption an‎d economic eva‎luation showed that the HC/UV/H₂O₂/PS process not only had the highest degradation percentage but also the lowest EE/O parameter value, which indicates the amount of energy consumption per pollutant degradation, with a value of 31.91667. Additionally, this process, with an ECR value of 593.0193, was selec‎ted as the most optimal method for removing the SDSB surfactant. Increasing the pollutant concentration from 10 mg.L-1 to 40 mg.L-1 leads to a decrease in the degradation rate from 98.204% to 66.92% an‎d a reduction in the rate constant from 100.5× 10-3min-1 to 62.3×10-3 min-1. The use of tert-butanol an‎d ethanol as free radical scavengers showed that the impact of free radicals was 83.5%, with the contribution of hydroxyl radicals being 33.81% an‎d the contribution of persulfate radicals being 67.18%. The direct effect of hydrodynamic cavitation an‎d UV irradiation was 16.5%.

اكسيداسيون پيشرفته , كاويتاسيون هيدروديناميك , سورفكتانت , اشعه فرابنفش , پرسولفات

Advanced oxidation , Hydrodynamic cavitation , Surfactant , UV light , Persulfate

Haniye Sajedi

Omid Vahidi, Soroush Bradaran