Application of a Definitive Screening Design and Optimal Augmentation to Characterize an Electro‐Fenton Process Combined With Anodic Oxidation on BDD Electrodes

The definitive screening design (DSD) represents a novel and highly efficient methodological approach that enables researchers to gain critical insights with minima experimental runs, significantly enhancing process efficiency and accelerating research outcomes. In this study, DSD was employed to examine the effects of nine process variables on the degradation of a textile dye using an electro-Fenton (EF) system with reticulated vitreous carbon (RVC) cathodes and boron-doped diamond (BDD) anodes. The primary goal was to assess the predictive capability of DSD in characterizing the complex EF system coupled with BDD electrodes and to optimize industrial dye treatment in wastewater, using a reduced experimental set. Only 23 experiments were needed to screen the effects of dye concentration, current density, NaCl and Na₂SO₄ concentrations, pH, temperature, interelectrode distance, stirring rate, and Fe²⁺ concentration. Subsequently, an optimal augmented design (OAD) was applied, adding eight more runs to refine the process characterization. Statistical analysis identified temperature, current density, and dye concentration as the key factors influencing total organic carbon (TOC) removal, with significant interactions observed between temperature and current density, and between pH and dye concentration. Under optimal conditions, a 73.1% reduction in TOC was achieved after 90 min. This study highlights the novel combination of DSD and OAD as a powerful approach for identifying critical process parameters and optimizing the treatment of industrial dyes in wastewater with reduced experimental effort and enhanced accuracy.