Advancing wastewater treatment: The efficacy of carbon-based electrochemical platforms in removal of pharmaceuticals

Abstract

The study addresses the efficiency of innovative biochar- and g-C3N4-coated electrochemical platforms in removing selected pharmaceuticals and their metabolites from wastewater, with a focus on cost-effective and scalable materials. Analysis of effluent from the wastewater treatment plant revealed significant concentrations of 25 pharmaceuticals, highlighting the plant’s limited treatment efficacy. Notably higher levels of Telmisartan, Tramadol, and Diclofenac were found. The novelty of this work lies in the use of biochar- and g-C3N4-coated Raschig rings and glass beads as efficient electrochemical anodes offering high degradation capabilities. Adsorption-only tests (without voltage load) confirmed that no significant pharmaceutical removal occurs without electrochemical activation, highlighting the importance of electrochemical degradation. For the first time, we observed the formation of hydroxyl radicals (•OH) and singlet oxygen (1O2) during the electrochemical degradation process using g-C3N4-coated anodes, significantly enhancing degradation efficiency. The biochar-coated Raschig rings achieved over 80 % removal efficiency for all tested pharmaceuticals, with a power consumption of 85.2 kWh/m3. In comparison, biochar-coated beads exhibited a removal efficiency ranging from 9 % to 99 %, consuming 75 kWh/m3, while g-C3N4-coated rings showed the lowest performance at an energy consumption of 45 kWh/m3. These findings demonstrate the potential of both, biochar- and g-C3N4-based electrochemical platforms as a viable, scalable solution for advanced wastewater treatment, particularly for pharmaceutical degradation.