Investigation of the regeneration of spent activated carbon from water treatment plants

Activated carbon is widely used as an adsorbent in wastewater treatment plants. Furthermore, its adsorption capacity decreases over time until reaching its adsorption leading to multiple wastes hazardous problems. However, spent activated carbon materials can be reactivated using multiple physical, chemical, and thermal approaches. In this study, we introduce a one-step low-cost method for regenerating spent activated carbon collected from wastewater treatment plant. Regenerated materials were then characterized to assess the impacts of both the temperature and activating agent (KOH and H₃PO₄) on their physicochemical and structural properties. The regenerated activated carbons displayed an enhancement in the specific surface area (e.g., 633 and 729 m² g⁻¹ using KOH and H₃PO₄, respectively) compared to the spent activated carbon (477 m² g⁻¹). The obtained materials were then used as electrodes for EDLC devices, demonstrating good stability and reversibility of 21 F g⁻¹ at a current density of 0.25 A g⁻¹ during cycling tests.