Abstract:

The electrocatalytic activity of a roughened silver electrode towards the reductive dehalogenation of 2,4,6-tribromophenol was compared to a glassy carbon electrode and a polished silver electrode in basic aqueous solution by cyclic voltammetry (CV). Furthermore, the course of reductive dehalogention of 2,4,6-tribromophenol was studied by CV and controlled-potential electrolysis. Results indicated that roughened silver exhibited more powerful electrocatalytic activity than the glassy carbon electrode and the polished silver electrode for the selective dehalogention of 2,4,6-tribromophenol. The reduction of 2,4,6-tribromophenol was determined to be a stepwise dehalogenation as follows: 2,4,6-tribromophenol→2,4-dibromophenol→2-bromophenol→phenol. In addition, the activity energy needed for the dissociative reduction of the ortho carbon-halogen bond was similar to the para carbon-halogen bond for 2,4,6-tribromophenol and a higher energy was probably required for 2,4-dibromophenol to cleave the ortho carbon-halogen bond compared to the para carbon-halogen bond.

Key words: Selective dehalogenation, 2,4,6-tribromophenol, Silver electrode, Waste water treatment