Plant-Cell mediated synthesis of MnCo2O4 nanoparticles and their activation of peroxymonosulfate to remove Tetracycline

Nanosized bimetallic oxides can efficiently activate peroxymonosulfate (PMS) to degrade organic pollutants attributed to their synergetic electron transfer between the two metals. However, their scalable and controllable synthesis remains challenging. In this study, small and regular MnCo 2 O 4 nanoparticles (NPs) were successfully synthesized via a facile bio-templating method. Leaf cells were used as structure-directing agents, and the nucleation and growth of MnCo 2 O 4 were restricted in the confined space of cells, resulting in MnCo 2 O 4 spinel with an average size of 22 nm. The MnCo 2 O 4 NPs can activate PMS to achieve 99 % degradation of TC ( C 0  = 20 mg·L −1 ) within 10 min. Moreover, the MnCo 2 O 4 NPs also show a wide applicable pH range (3.0 − 11.0, RE  > 94 %), excellent reusability ( RE =  96 % after four cycles), and good adaptability in the complex water matrix. Analysis of the catalytic mechanisms suggests that radical O 2 •− and non-radical 1 O 2 dominate this MnCo 2 O 4  + PMS + TC system. Besides, 17 major degradation intermediates of TC were identified (most of them were predicted to be harmless), and 3 possible degradation pathways were proposed. This study provides a feasible strategy for synthesizing spinel-structured MnCo 2 O 4 NPs, which show great potential in removing antibiotics from wastewater.