نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Chromium is a highly toxic and carcinogenic pollutant commonly found in industrial effluents such as electroplating, tanning, and dye manufacturing, posing a serious risk to human health and the environment. Among modern treatment methods, electrocoagulation has attracted wide attention due to its simplicity, high efficiency, and no need for external chemical coagulants. In this study, the removal of chromium from aqueous solutions using the EC process was investigated in two parts. In the first part, the effects of three key parameters: current density, initial concentration, and reaction time, on removal efficiency and operating cost were modeled and optimized using Response Surface Methodology. The results showed that current density had a consistently positive effect on removal efficiency, while the influence of reaction time depended on conditions, becoming significant only at current densities above 90 A/m² and in interaction with initial concentration. In contrast, increasing initial concentration had an inverse effect, reducing removal efficiency by up to 8.1%. Regarding operating costs, the effects of time and concentration were limited, while current density was the main driver, raising costs by up to 161.57% when increased from 48 to 132 A/m². In the second part, the role of electrode surface morphology was examined under optimized conditions, including one solid electrode and three perforated electrodes with hole diameters of 4, 8 and 15 mm. The findings indicated that perforated electrodes reduced removal efficiency due to decreased active surface area, with the 4 mm electrode lowering removal efficiency by 6.27%. However, hole diameter played a decisive role, as enlarging the diameter from 4 to 8 mm improved efficiency by 2.63%. Moreover, perforated electrodes significantly reduced operational costs, achieving up to 30.9% savings compared to solid electrodes. The reduction in operational cost with perforated electrodes is attributed to the lower system output voltage due to reduced active surface area and the decreased initial corrosion resistance at perforation edges, both of which lead to lower energy consumption and improved economic performance of the process. Overall, the results demonstrate that simultaneous optimization of operational conditions and electrode surface design can improve the efficiency and cost-effectiveness of the EC process for chromium removal. The perforated electrode with 8 mm holes was identified as the optimal choice, balancing high removal efficiency with reduced operating costs.
کلیدواژهها English
