Transformation characteristics of organic pollutants in Fered-Fenton process for dry-spun acrylic fiber wastewater treatment

The Fered-Fenton process using Ti sheet as cathode and RuO₂/Ti as anode was employed for the pretreatment of dry-spun acrylic fiber manufacturing wastewater. The effects of feeding mode and concentration of H₂O₂ on chemical oxygen demand (COD) removal efficiency as well as the biodegradability variation during the Fered-Fenton process were investigated. The feeding mode of H₂O₂ had significant influence on COD removal efficiency: the removal efficiency was 44.8% if all the 60.0 mM H₂O₂ was fed at once, while it could reach 54.1% if the total H₂O₂ was divided into six portions and fed six times. The biochemical oxygen demand/COD ratio increased from 0.29 to above 0.68 after 180 min treatment. The transformation characteristics of organic pollutants during the Fered-Fenton process were evaluated by using gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR) and fluorescence excitation-emission matrix (EEM) spectroscopy. Most of the refractory organic pollutants with aromatic structure or large molecular weight were decomposed during the Fered-Fenton process.