Cerium(IV)-mediated electrochemical oxidation process for removal of polychlorinated dibenzo-p-dioxins and dibenzofurans

In this study, Ce(III)/Ce(IV) redox couple mediated electrochemical oxidation (MEO) process for degradation of liquid 2,3,7,8-TCDD (tetrachloro dibenzo-p-dioxin) and PCDD/Fs (polychlorinated dibenzo-p-dioxins/dibenzofurans) from fly ash was developed. The highest concentration of Ce(IV) was achieved under operation at 80 °C, current density of 10 A cm−2 with 0.9 M feed concentration of Ce(III) in atmospheric pressure. Both the liquid and fly ash samples reacted with electrogenerated Ce(IV) in 10 s using batch reactor and the obtained results were presented in the form of International Toxic Equivalent quantity (I-TEQ) and pg L−1. After reaction with Ce(IV), the concentration of the highly toxic liquid isomer 2,3,7,8-TCDD found 2.96 pg g−1 I-TEQ from the initial value of 1200 pg g−1 I-TEQ that is equal to the removal efficiency of 99.75%. HRMS data demonstrated the fly ash, the total PCDD/Fs concentrations, decreased to 33.16 pg g−1 I-TEQ from the initial value of 58 pg g−1 I-TEQ, which is equal to removal efficiency of 42.8%. The developed Ce(III)/Ce(IV) MEO process provides potential removal of PCDD/Fs in short time from the emissions of industrial waste incinerators.