Search

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. [ABSTRACT FROM AUTHOR]

A two-step treatment process has been investigated for effective textile effluent management. In step I, the effluent was decolorized via chlorine-mediated indirect electrooxidation (InDEO), while H2O2 was electrogenerated during step II in the decolorized textile effluent, by employing an H-type divided electrochemical cell. The native salts present within the decolorized textile effluent (9.4 g/L Na2SO4 and 0.8 g/L NaCl) were exploited as electrolytes for the catholyte, whereas 0.5 N sulfuric acid was used as the anolyte for the in situ electrochemical generation of H2O2. During the cyclic voltammetry tests, O2 reduction at the activated carbon felt cathode was observed around -0.86 V versus saturated calomel electrode (SCE) at a scan rate of 100 mV/s. Under optimized conditions (cathode potential of -0.9 V vs. SCE and catholyte at pH 6) about 1.45 ± 0.01 mM H2O2 have been generated. The effluent containing H2O2 was subjected to Fenton reaction and the generation of OH• radicals was confirmed by electron paramagnetic resonance spectroscopy. The results indicated a 59% reduction of the chemical oxygen demand; significant modifications of the functional groups were observed by Fourier transform IR spectroscopy. High performance LC analysis confirmed the degradation of the organic compounds during the oxidative treatment process. These findings suggest the application of this method for degradation of highly colored textile effluents. [ABSTRACT FROM AUTHOR]