A novel sulfite coupling electro-fenton reactions with ferrous sulfide cathode for anthracene degradation

In the present study, pyrite modified carbon felt (FeS2/CF) was used as cathode in electrochemical advanced oxidation for the first time. The FeS2/CF cathode can provide Fe(II) and oxysulfide continuously through this sulfite coupling heterogeneous electro-Fenton (HEF) process without leaching of iron, which further induced the formation of SO4 center dot(-) and center dot OH. The cumulative concentration of center dot OH was 26.83 mu M after 20 min at the current density of 10 mA cm(-2), which was about twice higher than that in the electrochemical system with CF only. The estimated steady-state concentrations of SO4 center dot(-) and center dot OH in this HEF system can be as high as 7.37 x 10(-4) mu M and 2.44 x 10(-4) mu M, respectively. This electrochemical system with FeS2/CF cathode shows remarkable efficiency ( > 80%) for anthracene (ANT) degradation in a wide pH of 3-9, and can be used for at least six times. The major degradation products of ANT were identified as anthraquinone and other four hydroxylated products. The study provides a novel aspect of FeS2 in HEF processes, and is expected to be an efficient technology in water treatment processes.