Electrochemical degradation of aspirin using a Ni doped PbO2 electrode

The novel nickel modified PbO 2 electrodes were successfully prepared via electrodeposition in nitrate solution. The influence of nickel content on the physico-chemical properties and electrocatalytic performance of PbO 2 electrodes was investigated. The electrodes were characterized by SEM, EDX and XRD techniques. A limited amount of doping nickel could produce a more compact PbO 2 film and diminish the size of the crystal grains. The steady-state polarization curves and the cyclic voltammetry analysis showed that the 1% Ni–PbO 2 electrode had the highest oxygen evolution potential and the optimal electrochemical oxidation ability. The cyclic voltammograms with various scan rates showed that the oxidation of aspirin on these PbO 2 electrodes was a typical diffusion-controlled electrochemical process. Stability tests of different PbO 2 electrodes showed that 1% Ni–PbO 2 electrode had the highest electrochemical stability. In addition, nickel modified PbO 2 electrodes were used to degradation aspirin in aqueous solution, which gave the direct evidence of the electrocatalytic capabilities of these electrodes. The results showed that 1% Ni–PbO 2 electrode obtained the highest kinetic rate constant, chemical oxygen demand (COD) and total organic carbon (TOC) removals, which were 1.41, 1.22, 1.20   times than those of undoped PbO 2 electrode, respectively. Moreover, the energy required for the treatment of 1   m 3 aspirin solution significantly decreased and the hydroxyl radical utilization rate was enhanced after appropriate nickel doping. As a result, the 1% Ni–PbO 2 electrode is a promising anode for the treatment of organic pollutants.