Constructing a brand-new advanced oxidation process system composed of MgO2 nanoparticles and MgNCN/MgO nanocomposites for organic pollutant degradation

Abstract

A brand-new advanced oxidation process (AOP) system consisting of MgO₂ nanoparticles and MgNCN/MgO nanocomposites was firstly developed for the degradation of organic pollutants. In the novel AOP system, MgO₂ nanoparticles as oxidants and MgNCN/MgO nanocomposites as activators were both obtained through a simple one-step process. Batch experiments indicated that the MgO₂–MgNCN/MgO system could efficiently degrade organic pollutants in a wide pH range (4–12), and the degradation efficiency was hardly affected by common matrix species (Cl⁻, NO₃⁻, HCO₃⁻, SO₄²⁻ and humic acid) and water sources. The high stability and slow-release characteristic of MgO₂ endowed the AOP system with a long-term oxidation ability for continuous degradation of organic pollutants. The dominant reactive oxygen species (ROS) responsible for organic degradation was confirmed to be singlet oxygen (¹O₂), which was attributed to the activation of MgO₂ by the bonding effect between MgNCN and MgO in the nanocomposites. Finally, the generated ions, NH₄⁺, NO₂⁻ and NO₃⁻, and residual solid in the degradation solution were determined, and the process of organic degradation in the MgO₂–MgNCN/MgO system was proposed. This work not only constructed a brand-new AOP system for environmental remediation, but also offered a promising strategy for continuous treatment of organic-polluted wastewater and even soil.