Removal of EDTA-Cu(II) from Water Using Synergistic Fenton Reaction-Assisted Adsorption by Nanomanganese Oxide-Modified Biochar: Performance and Mechanistic Analysis

Metal complexes exhibit higher stability in water, making metal removal more challenging. In this study, a low-cost, high-efficiency, and multifunctional nanomanganese oxide-modified biochar (BC-MnOx) was used for synergistic adsorption processes and Fenton reaction catalysis to achieve the removal of EDTA-Cu(II). Using this system, the Cu and total organic carbon removal efficiencies reached 94.67% and 92.79%, respectively. Mechanistic analysis indicated that multifunctional BC-MnOx catalyzed the Fenton reaction to generate hydroxyl radicals (HO•) capable of attacking the EDTA-Cu(II) complex structure and releasing low-molecular weight organic matter-Cu compounds due to the simultaneous decarboxylation at different positions, which were concurrently adsorbed by modified biochar. The modified biochar assessed in this study offers high-efficiency Cu complex removal, high stability, low cost, and widespread availability, laying a promising foundation for its practical applicability and potential suitability for the removal of other metal complexes.