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

Abstract

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 °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, pyridinic N and C3PO 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.