La-doped Ti/Sb-SnO2 electrode enhanced removal of microplastics by advanced electrocatalysis oxidation process (AEOP) strategy

Abstract Microplastics (MPs) in the aqueous environments has attracted widespread attention because of its potential risk to human health .Its high stability makes it difficult to be degraded and long term presence in the environment. Therefore, it is crucial to find an efficient and clean technology to remove microplastics in water. The advanced electrocatalysis oxidation process (AEOP) shows great potential for application. In this work, We focused on preparing Ti/Sb-SnO2 electrodes doped with different rare earth elements (La, Ce, Sm or Nd) as active layer by sol-gel method. The electrooxidation system has efficiently degraded MPs in aqueous solution. The optimal parameters for the removal of MPs were electrode spacing of 1.5 cm, current density of 46.67 mA cm-2, Na2SO4 electrolyte concentration of 0.22 mol·L-1, and initial solution pH of 7. After 3 h, MPs removal rate by Ti/La-Sb-SnO2 system reached 28.3 %, which was higher than the Ti/Ce-Sb-SnO2, Ti/Sm-Sb-SnO2, Ti/Nd-Sb-SnO2 and Ti/Sb-SnO2 electrode, the removal rates were increased by 8.23 %, 10.13 %, 16.28 % and 77 %, respectively. Electrochemical performance tests and •OH (Hydroxyl radicals) generation results indicated that the surface of Ti/La-Sb-SnO2 electrode had abundant active sites, which promoted the formation of •OH to degrade microplastics effectively. In summary, the rare earth element-doped Ti/Sb-SnO2 electrode provides crucial technological support for the electrooxidative removal of microplastics from water.