Nanocarbon shells with self-inherent N, P derived from chlorella pyrenoidosa for aqueous catalytic ozonation: nonradical-dominated mechanisms

Nanocarbon shells with self-inherent N, P derived from waste chlorella pyrenoidosa (CP) as N/P/C precursors were prepared for the first time using a one-step pyrolysis method to remove ibuprofen (IBU) for catalytic ozonation. The CP at 1000 degrees C (NPC1000) had superior catalytic ozonation performance over MnO2, Al2O3, and g-C3N4. The catalytic ozonation process follows a nonradical oxidation mechanism via surface adsorbed atomic oxygen (*Oad), singlet oxygen (1O2) and electron transfer pathway. The result indicated that graphitic N, pyr-idinic N and C3-P--O functional groups were the major active sites based on the correlation between material structure and catalytic performance. Furthermore, the catalytic activity has little impact on the removal of IBU wastewater containing inorganic anions and humic acid (HA). This study opens new applications for microalgae-derived biocarbon materials and provides a new insight into the mechanism of metal-free heterogeneous ozone catalyst.

Automated summary

In this study, nanocarbon shells with self-inherent N, P derived from waste chlorella pyrenoidosa were prepared for catalytic ozonation, which showed superior performance compared to other common catalysts. The catalytic ozonation process followed a nonradical oxidation mechanism involving surface adsorbed atomic oxygen, singlet oxygen, and electron transfer pathway. The major active sites were identified as graphitic N, pyr-idinic N, and C3-P--O functional groups. Furthermore, the catalytic activity was found to be unaffected by the presence of inorganic anions and humic acid in the wastewater.