Catalytic ozonation of atrazine with stable boron-doped graphene nanoparticles derived from waste polyvinyl alcohol film: Performance and mechanism

Abstract

To prepare a high-performance catalyst for heterogeneous catalytic ozonation (HCO) of atrazine (ATZ, a refractory pollutant) in water, graphene nanoparticles (GNPs) were successfully prepared by facile in situ pyrolysis method. Waste polyvinyl alcohol film was chosen as carbonaceous precursor in a “waste-to-treasure” strategy. By introducing boron (B) in the synthesis, the obtained B-doped GNPs (B-GNPs) exhibited more robust HCO performance. The ATZ degradation efficiencies by ozonation, GNPs, and B-GNPs catalytic ozonation after 10 min were 40.2 %, 69.8 %, and 83.2 %, respectively. In contrast to ozone activation in GNPs induced by oxygenated defects, boronated defects dominated ozone decomposition and subsequent reactive oxygen species generation (OH and O2–), imparting B-GNPs with greater activity and stability. Generally, B-doping promoted the electron transfer of B-GNPs, thus enhancing ozone adsorption and degradation. Also, the effect of various water matrices on ATZ degradation during HCO was comprehensively evaluated. Acute toxicity tests indicated rapid detoxification through deep ATZ degradation by B-GNP-catalyzed ozonation. This study provides a robust and efficient carbonaceous catalyst based on a “waste-treats-waste” strategy for environmental remediation, thereby providing insights into the mechanism and application of heteroatom-doped carbonaceous catalysts for the HCO process.