Kinetics of aniline degradation by Fenton and electro-Fenton processes

Abstract

Aniline degradation at pH 2 by Fenton and electro-Fenton processes was kinetically investigated in this study. Electro-Fenton process was found to be superior to ordinary Fenton process with the current impacts of 1.2 to 3.1 for removal efficiency and 1.2 to 5.8 for degradation rate depending on initial Fe 2+ concentration. This is mainly due to the rapid electrochemical regeneration of Fe 2+. Overall rate equations for aniline degradation by Fenton and electro-Fenton processes (in units of molar and minute) are: ( d [ Aniline ] d t ) Fenton = - 6.4 × 1 0 - 3 [ Fe 2 + ] - 1.23 [ H 2 O 2 ] 1.58 [ Aniline ] 1.10 ( d [ Aniline ] d t ) electro ‐ Fenton = - 2.6 × 1 0 - 3 [ Fe 2 + ] 0.08 [ H 2 O 2 ] - 0.14 [ Aniline ] 0.46 With current application, aniline degradation rate seems to be autonomous from Fenton's reagent concentrations and approaching a half order with respect to aniline. In addition, for complete removal of 0.01 M aniline, the delay in current supply at the initial stage could save up to one-third of the total energy required by the ordinary electro-Fenton process. As a result, significant reduction in energy consumption and operating cost could be obtained by the current-delay operating mode.