Optimization and analysis of homogenous Fenton process for the treatment of dry-spun acrylic fiber manufacturing wastewater

In this study, the homogenous Fenton process was employed for the pretreatment of dry-spun acrylic fiber (DAF) manufacturing wastewater. Central composite design and response surface methodology (RSM) were used for the design and optimization of the Fenton process. A second-order polynomial regression equation was developed to describe the chemical oxygen demand (COD) removal efficiency of Fenton process and validated by the analysis of variance and residual techniques. The interaction effects of the operational parameters were investigated using response surface analysis. The optimum parameters were determined as 90.00 mM H₂O₂, 30.00 mM Fe²⁺, pH of 3.14, and reaction time of 114 min. Under the optimum reaction conditions, the COD removal efficiency was 47.1%, which was highly consistent with the value predicted by the model equation, with a deviation of 2.89%. Furthermore, the biodegradability and toxicity of raw and treated wastewater were compared; the results showed that the (BOD₅)/COD (B/C) ratio increased from 0.35 to 0.67, whereas the light loss of Vibrio fisheri bacteria decreased from 92 to 31%. The Fenton process was an effective method for pretreating DAF wastewater, and RSM was suitable for process design and optimization.