Bacterial Cellulose-Derived Biochar for Electrochemically Assisted Fenton Degradation of Methylene Blue

This study explores the potential of biochar derived from bacterial cellulose (BC-derived biochar) as a catalytic support in Fenton-type processes for the degradation of methylene blue (MB) in aqueous solutions. The biochar was synthesized by modifying purified BC membranes with Fe²⁺/Fe³⁺ ions, followed by calcination at 400 °C. The performance of three treatment approaches (electrochemical degradation, heterogeneous Fenton process, and a combined treatment integrating both methods) was evaluated. The results highlighted the superior efficiency of the combined treatment, demonstrating its potential for practical applications. A 2³ factorial design with a central point was employed to evaluate the effects of key variables in the electrochemically assisted Fenton process: MB concentration, BC-derived biochar concentration, and reaction pH. Statistical analysis, with an <i>R</i> ² value of 0.989, revealed that only the dye concentration and biochar concentration had statistically significant effects, while pH and interaction effects were negligible. Discoloration efficiencies reached nearly 80% for 10 ppm solutions at both acidic and basic pH, with a maximum treatment time of 60 min, demonstrating the versatility and effectiveness of the Fenton system in diverse media. Additionally, a kinetic study further supported these findings, with the best result fitting a first-order reaction model (<i>R</i> ² = 0.984). The total organic carbon analysis confirmed the method's efficiency, showing a reduction in the organic compound by over 50% for both 10 and 55 ppm solutions. These results demonstrate that the proposed method is a promising alternative for treating MB dye and can be extended to the degradation of other organic compounds.