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

Abstract

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 10Acm−2 with 0.9M feed concentration of Ce(III) in atmospheric pressure. Both the liquid and fly ash samples reacted with electrogenerated Ce(IV) in 10s using batch reactor and the obtained results were presented in the form of International Toxic Equivalent quantity (I-TEQ) and pgL−1. After reaction with Ce(IV), the concentration of the highly toxic liquid isomer 2,3,7,8-TCDD found 2.96pgg−1 I-TEQ from the initial value of 1200pgg−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 33.16pgg−1 I-TEQ from the initial value of 58pgg−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.