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

Abstract

ABSTRACT 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.