Non-radical activation of CaO2 nanoparticles by MgNCN/MgO composites for efficient remediation of organic and heavy metal-contaminated wastewater

Stable, cheap and environmentally friendly CaO2 was widely used to remediate environmental pollution, especially in advanced oxidation process (AOP) systems. However, its non-radical activation was still a huge challenge. In this study, the non-radical activation of CaO2 nanoparticles was realized by MgNCN/MgO composites for efficient remediation of organic and heavy metal-contaminated wastewater. The presented CaO2-based AOP system exhibited excellent degradation performance towards tetracycline (TC) and methylene blue (MB) over a broad pH range, accompanied with the weak influences of common coexisting anions and natural water sources. Singlet oxygen (1O2) was verified as the dominant active species for organics degradation, and the coordination between MgNCN and MgO in MgNCN/MgO composites played a crucial role in the non-radical activation of CaO2 nanoparticles. More importantly, the AOP system could not only degraded effectively organic pollutants, but also remove simultaneously heavy metal ions in wastewater. 100 mg/L CaO2 and MgNCN/MgO could successfully remediate the complex pollution consisting of 10 mg/L MB and 100 mg/L Cd2+. Furthermore, the degradation intermediates of MB and the solid residues after treating pollutants were analyzed in detail to reveal the degradation process and conversion products.