Green-Activated Charcoal-Anchored Iron Oxide-Driven Microbial Electro-Fenton System for Sustainable Mitigation of Refractory Contaminants

The contamination of natural water bodies with dyes and other refractory compounds is a menacing issue in developing nations. Despite stringent laws, industrial effluent is not managed efficiently, as it incurs additional cost. Hence, the present research focuses on sustainable mitigation of refractory contaminants using a self-driven bioelectro-Fenton (BEF) system. The iron-activated charcoal (Gt-Fe/AC) cathode-cum-Fenton catalyst used in this investigation was synthesized using waste green tea extract as a biogenic agent. The green catalyst-driven BEF system (Gt-Fe/AC-MFC) achieved a maximum power density of 111.7 ± 3.1 mW/m² and a maximum operating voltage of 108 ± 3 mV, while parallelly degrading 20 mg/L of Coomassie Brilliant Blue (CBB) dye almost entirely in 300 min at a neutral pH. Additionally, high removal of Congo red dye (96.8 ± 1.2%) and methylparaben (90.9 ± 0.6%) was attained under similar operating conditions. Moreover, the Fe-AC-catalyzed BEF performed fairly well in treating spiked real wastewater and exhibited remarkable stability, with only a 3% decrease in CBB removal efficiency after 10 continuous cycles and 0.11% drop in cathodic current per cycle. Hence, this BEF system can be a sustainable oxidative technology to tackle refractory wastewater in resource-constricted regions.