Treatment of Shale Gas Flowback Wastewater by Electroflocculation Combined with Peroxymonosulfate

In this study, potassium peroxymonosulfate was added to an electrolytic cell with an iron anode to achieve the dual flocculation and sulfate-radical-driven oxidative degradation of organic matter in shale gas flowback wastewater. The effects of current density, solution pH, and potassium peroxymonosulfate concentration on organic matter degradation were investigated. The results showed that chemical oxygen demand (COD) removal reached 93.4% at a current density of 40 mA/cm2, pH 7, and a potassium peroxymonosulfate concentration of 1500 mg/L, surpassing the efficiency of single electroflocculation (82.4%). The characterization of the coupled electroflocculation and peroxymonosulfate system confirmed the production of sulfate radicals and identified Fe2O3 as the primary final product in the treated wastewater. The introduction of sulfate significantly enhanced organic matter degradation, accelerated the reaction rate and improved the overall efficiency of the treatment process. This study offers valuable insights into the chemical synergistic treatment approach and its potential applications in organic wastewater treatment.