Response surface methodology as a tool to optimize the electrochemical incineration of bromophenol blue on boron-doped diamond anode

• Boron-doped diamond was used to degrade bromophenol blue.
• BPB degradation was greatly influenced by all the studied operating variables.
• Total removal of BPB may be achieved at reasonable time and energy consumption.
• The sulfate concentration displayed abnormal effects on all response factors.

This study investigated the electrochemical incineration of bromophenol blue (BPB) at boron-doped diamond (BDD) anode. The individual and interaction effects of three control parameters (applied current density, flow rate and supporting electrolyte concentration) on process efficiency were estimated by central composite rotatable design. Among the independent variables, supporting electrolyte concentration displayed the most interesting roles on BPB degradation. The optimal conditions obtained by response surface methodology were: applied current density of 7.36 mA cm− 2, 2.6 mM Na2SO4 and flow rate of 568 ml min− 1, which gave a decolorization rate of 91.7% and a mineralization rate of 47.3%, as well as an energy consumption of 3518.89 kWh kg− 1 TOC (7.0 kWh m− 3) and a mineralization current efficiency of 15.1% at 120 min of electrolysis. The results presented here demonstrated the high efficiency of BDD technology in mineralizing BPB under mild conditions, as well as the usefulness and capability of the experimental design strategy for successful investigation and modeling of the electrocatalytic processes.