Electrochemical degradation of acrylic acid using Ti/Ta2O5-IrO2 electrode.

Abstract

Acrylic acid (AA) is widely used as a raw material in the industrial production of various chemicals. Its extensive use has produced environmental problems that need to be solved. The Ti/Ta2O5-IrO2 electrode, a type of dimensionally stable anode, was used to investigate the electrochemical deterioration of AA. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis showed that IrO2 existed as an active rutile crystal and as a TiO2-IrO2 solid solution in Ti/Ta2O5-IrO2 electrode with a corrosion potential of 0.212 V and chlorine evolution potential of 1.30 V. The effects of current density, plate spacing, electrolyte concentration, and initial concentration on the electrochemical degradation of AA were investigated. Response surface methodology (RSM) was used to determine the ideal degradation conditions: current density 22.58 mA cm-2, plate spacing 2.11 cm, and electrolyte concentration 0.07 mol L-1, and the highest degradation rate reached was 95.6%. Free radical trapping experiment verified that reactive chlorine played a dominant role in the degradation of AA. The degradation intermediates were analyzed by GC-MS.