Saturated activated carbon regeneration by UV-light, H2O2 and Fenton reaction

The economic viability of using adsorption is associated with the ability to regenerate and/or reuse the adsorbent material. Thus, in this work, the regeneration of activated carbon used for methylene blue adsorption was evaluated applying photolysis, oxidation with hydrogen peroxide and Fenton reaction. The regeneration efficiency of these methods was evaluated, and the material was characterized by Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray-dispersive energy spectroscopy (EDS). During photolysis, the saturated activated carbon was exposed to a source of UV radiation for different times and the results showed that a maximum of 30% regeneration was achieved after 2 h of reaction. For the tests applying oxidation by H2O2, the results showed that a maximum of 40% regeneration was achieved when the concentration of the oxidizing agent was 50 mmol L-1. On the other hand, a synergistic effect of coal-Fe was observed in the Fenton reaction, reaching a maximum of 71% regeneration. In addition, the stability of the material was evaluated through adsorption-regeneration cycles and the results showed in general that the Fenton reaction conferred greater stability and the material's adsorption capacity was recovered for 7 consecutive cycles.