Electrochemical degradation of aspirin using a Ni doped PbO2 electrode

• Novel nickel modified PbO2 anodes are prepared and optimized.
• The physico-chemical properties of nickel modified electrodes were discussed.
• Mechanism of Ni doped PbO2 electrode were analyzed.
• Aspirin undergoes efficient degradation and mineralization using this anode.

The novel nickel modified PbO2 electrodes were successfully prepared via electrodeposition in nitrate solution. The influence of nickel content on the physico-chemical properties and electrocatalytic performance of PbO2 electrodes was investigated. The electrodes were characterized by SEM, EDX and XRD techniques. A limited amount of doping nickel could produce a more compact PbO2 film and diminish the size of the crystal grains. The steady-state polarization curves and the cyclic voltammetry analysis showed that the 1% Ni–PbO2 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 PbO2 electrodes was a typical diffusion-controlled electrochemical process. Stability tests of different PbO2 electrodes showed that 1% Ni–PbO2 electrode had the highest electrochemical stability. In addition, nickel modified PbO2 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–PbO2 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 PbO2 electrode, respectively. Moreover, the energy required for the treatment of 1 m3 aspirin solution significantly decreased and the hydroxyl radical utilization rate was enhanced after appropriate nickel doping. As a result, the 1% Ni–PbO2 electrode is a promising anode for the treatment of organic pollutants.