A feasible treatment of carpet-washing wastewater through the electro-fenton process: optimization using response surface methodology

Abstract

Wastewater from carpet washing has yet to be extensively studied despite its high volume and pollution load due to complex hazardous materials and high organic content. This study examined the feasibility of using Electro-Fenton (EF) processes to remove chemical oxygen demand (COD) from carpet washing wastewater (CWW) generated by the Nickpour Industry in Iran. COD removal was used to assess the total organic content. Anionic surfactants, especially Linear Alkylbenzene Sulfonate (LAS), are widely used in household and industrial detergents. The study utilized an experimental design using response surface methodology (RSM) based on the Box–Behnken method to evaluate the setup's effectiveness and optimize the conditions. Five independent factors, including H2O2/COD ratio, reaction time, effective surface area, pH, and applied voltage, were used as indicators to optimize the reaction parameters. Although LAS elimination reduced turbidity, the results showed that effective surface area and pH had a more significant impact on COD removal than other variables. The interactions between different parameters also had a significant effect on the results. Under the optimal conditions of a 1.8 H2O2/COD ratio, 3 cm2 electrode surface area, 30 minutes of reaction time, 23 V applied voltage, and an initial pH of 3, the study achieved a COD removal rate of 97.99%, a 99.92% removal of LAS, and a reduction of turbidity by up to 99.99%.

Keywords

• electro-fenton
• linear alkylbenzene sulfonate
• carpet washing
• response surface methodology