1,4-dioxane degradation using a pulsed switching peroxi-coagulation process

Abstract

Widely used in chemical product manufacture, 1,4-dioxane is one of the emerging contaminants, and it poses great risk to human health and the ecosystem. The aim of this study was to degrade 1,4-dioxiane using a pulsed switching peroxi-coagulation (PSPC) process. The electrosynthesis of H2O2 on cathode and Fe2+ production on iron sacrifice anode were optimized to enhance the 1,4-dioxane degradation. Under current densities of 5 mA/cm2 (H2O2) and 1 mA/cm2 (Fe2+), 95.3 ± 2.2% of 200 mg/L 1,4-dioxane was removed at the end of 120 min operation with the optimal pulsed switching frequency of 1.43 Hz and pH of 5.0. The low residual H2O2 and Fe2+ concentrations were attributed to the high pulsed switching frequency in the PSPC process, resulting in effectively inhibiting the side reaction during the ·OH production and improving the 1,4-dioxane removal with low energy consumption. At 120 min, the minimum energy consumption in the PSPC process was less than 20% of that in the conventional electro-Fenton process (7.8 ± 0.1 vs. 47.0 ± 0.6 kWh/kg). The PSPC should be a promising alternative for enhancing 1,4-dioxane removal in the real wastewater treatment. HIGHLIGHTS 1,4-dioxiane was efficiently removed in the PSPC process.; Residual H2O2 and Fe2+ were minimized by optimizing pulsed switching circuits.; The energy consumption in the PSPC reduced to 20% of that in the EF.;

Keywords

• 1,4-dioxane degradation
• electro-fenton
• pulsed switching circuit
• sacrifice iron anode