Enhanced electrocatalytic oxidation of high-salinity quaternary ammonium compound wastewater using CNTs-(RuₓIrᵧO₂)/Ti Anode

The organic pollutants, such as quaternary ammonium compounds, in high salinity flowback water from shale gas extraction may pose a severe risk to public health. Conventional biological technologies have limited effectiveness in the treatment of high-salt wastewaters, whereas electrocatalytic oxidation has shown potential for treating organic pollutants in high-salt flowback water. This study developed a carbon nanotubes (CNTs) doped Ru/Ir oxide coated Ti electrode CNTs-(Ru x Ir y O 2 )/Ti, which exhibited enhanced electrocatalytic performance for the treatment of quaternary ammonium compound in high-salt wastewater compared to the control metal oxide coated Ti anode (Ru x Ir y O 2 )/Ti, with pseudofirst-order reaction rate constant improved from 7.36 × 10 −3 to 1.12 × 10 −2 min −1 . Moreover, the CNTs-(Ru x Ir y O 2 )/Ti anode electrocatalytic oxidation system exhibited excellent cycling stability. Mechanism studies indicated that the CNTs-(Ru x Ir y O 2 )/Ti electrode enhanced singlet oxygen ( 1 O 2 ) generation, which played a major role in pollutant degradation. Furthermore, the formation of high concentrations of HClO and H 2 O 2 further facilitated the generation of 1 O 2 . This study may provide an efficient and green technology for the treatment of organic pollutants in high-salt shale gas flowback water.