Comparative study on electrochemical degradation of 4-chlorophenol by different Pd/C gas diffusion electrodes

Abstract

Pd/C catalyst used for the Pd/C gas diffusion cathodes was prepared by hydrogen reduction method and formaldehyde reduction method, and characterized by X-ray diffraction (XRD), transmission electrode microcopy (TEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques. The electrochemical degradation of 4-chlorophenol was investigated in the diaphragm electrolysis system, aerating firstly with hydrogen gas then with air, using three different kinds of gas diffusion cathode. The results indicated that the self-made Pd/C gas diffusion cathode can not only reductively dechlorinate 4-chlorophenols by aerating hydrogen gas, but also accelerate the two-electron reduction of O 2 to hydrogen peroxide (H 2 O 2 ) by aerating air. Therefore, the removal efficiency of 4-chlorophenol by using Pd/C gas diffusion cathode is better than that of the C/PTFE gas diffusion cathode (no catalyst). The catalytic activity of Pd/C catalyst prepared by hydrogen reduction method is higher than that prepared by formaldehyde reduction method. The stability of the Pd/C gas diffusion cathodes is good. Therefore, both the removal efficiency and the dechlorination degree of 4-chlorophenol reached about 100% after 60 min, and the removal efficiency of 4-chlorophenol in terms of chemical oxygen demand (COD) in the cathodic compartment reached 87.4% after 120 min. electrochemical oxidation, gas diffusion cathode, Pd/C catalyst, chlorophenol

Phenol Degradation: Numerical Simulation in a Stirred Tank Electrochemical Reactor

“…Electrochemical methods (EM) for destruction of organic pollutant in wastewater has been attracted the attention, since this is a powerful clean method which environmentaly-frienly [19]. EM has the advantage over the traditionally biological treatment since this is not suitable for the degradation of chlorinated compounds, in the case of phenol, it can be toxic for the microorganism [8].…”