Role of cerium modification on LDHs applied in three-dimensional electrochemical reactor for N-nitrosopyrrolidine disinfection by- products abatement in water

Abstract

A three-dimensional electrochemical reactor (3DER) with Ce-modified CoFe-LDHs as particle electrodes is assembled and used to efficiently degrade N-Nitrosopyrrolidine (NPYRs) in disinfected water. The construction of hierarchical structure and oxygen vacancies accelerates the electron transfer rate, provides a suitable working potential range and reduces electrochemical resistance, which leads to improved removal efficiency. The optimised particle electrodes (Co₂Fe_0.84Ce_0.16-LDHs@AC) achieved NPYR degradation of 81.5 % after 120 min of continuous treatment with low energy consumption of 2.4 kWh mg^–1 NPYR (current density of 5 mA cm⁻², flow rate of 3 mL min⁻¹, electrolyte concentration of 0.21 mol L⁻¹, and a pollutant concentration of 10 mg L⁻¹). Based on GC-MS, LC-MS analysis and quenching experiments, the degradation pathway of NPYR is proposed, while reactive oxygen species (ROS) during the degradation process include •OH, O₂^•− and ¹O₂. The modification of Ce in LDHs has a significant role in enhancing degradation efficiency by accelerating the formation of ROS, which provides an efficient solution to the material design used in the 3DER system for boosting pollution degradation during water treatment.