Electrochemical regeneration of carbendazim-loaded granular activated carbon

This study explores the use of in situ electrochemical process to regenerate granular activated carbon (GAC) loaded with carbendazim (CBZ) and simultaneously oxidize the contaminant. The experiment optimized the flow rate ($Q$Q), current density ($j$j), cathodic or anodic chamber, and electrolyte type to achieve the best results. The study found that using GAC in the cathodic chamber and NaCl as a supporting electrolyte, with a $j$j = 0.5 mA cm-2, and $Q$Q = 100 L h-1, led to a 64% regeneration with an energy consumption of 0.15 kWh kg-1, which is at least 16x lower than those found in the literature for electrochemical, microwave and thermal processes. Consecutive regeneration tests revealed a decrease in GAC adsorptive capacity over time due to blockage by transformation products, and mainly by oxidation-induced changes in pore structure, as confirmed in dissolved organic carbon (DOC), scanning electron microscopy (SEM), and surface area results. The results also showed that in all tested conditions, residual CBZ was not found in the electrolyte solution. Overall, electrochemical regeneration proved to be an energy-efficient method for extending the lifespan of GAC and minimizing disposal in landfills.