Glucose driven self-sustained electro-Fenton platform for remediation of 2,4-dichlorophenoxy herbicide contaminated water

As electrochemical oxidation technologies are energy-intensive, they are sparsely included in wastewater treatment plants. This study demonstrates a self-reliable glucose driven-electro-Fenton (GD-EF) system for decontamination of 2,4-dichlorophenoxy (2,4-D) herbicides without the supply of external current or voltage. It incorporates a cathode (graphite) which accepts electrons from abiotic glucose oxidation at anode (Pt/Ti or BDD or PbO₂/Cu/Ti) and generates in situ H₂O₂. For the first time, the ability of Pt/Ti, BDD, and PbO₂/Cu/Ti anodes in GD-EF and their influence on 2,4-D decontamination rate have been studied. Pt/Ti and PbO₂/Cu/Ti exhibited maximum power densities of 60.42 and 219.3 µW cm^-2, respectively than BDD (2.418 µW cm^-2). Even though Pt/Ti fuel cell exhibited lower power density than the PbO₂/Cu/Ti - fuel cell, it had a faster 2,4-D degradation rate of k = 18 × 10^-3 s^-1. The generated cathodic potential of -0.275 mV vs. Ag/AgCl in the Pt/Ti-fuel cell was sufficient to produce 23 mg L^-1h^-1 of H₂O₂. The high performance liquid chromatography analysis reveals the complete transformation of 2,4-D in 540 min and its degradation by 95% in 1080 min. This finding paves the way for greener decontamination of bio-recalcitrant herbicides with zero electrochemical energy consumption.