Synergistic effect of high-valent cobalt oxo species and piezoelectricity on enhanced peroxymonosulfate activation for atrazine removal.

[Display omitted] • Synergy of Co(IV) with piezoelectricity of BaTiO 3 was proposed. • DFT calculations are adopted for in-depth understanding of synergy. • Variation in energy barrier improve PMS activation. • Biochar as a supporting greatly reduced Co ion leaching. • The degradation pathway and toxicity of atrazine and intermediates are described. Co-based catalysts, especially the role of high-valent cobalt oxo species (Co(IV)) have made considerable progress in the field of the advanced oxidation process based on peroxymonosulfate. Nevertheless, the unsatisfactory efficiency drives to find of a suitable method to enhance the electron transfer for the improved performance of Co-based catalyst/PMS systems. Here, Enteromorpha-derived biochar modified with cobalt and barium titanate (CoBCBa) was prepared by pyrolysis. It can completely remove atrazine (10 mg/L) within 30 min under ultrasonic, and exhibited strong environmental tolerance. The superior performance of CoBCBa is attributed to the synergistic effect of Co(IV) and the piezoelectricity of BaTiO 3. The apparent reaction rate under the ultrasonic condition was 1.61 times higher than that non-ultrasonic condition. The density functional theory calculation indicates that the reduction of the energy barrier in the CoBCBa/PMS system is beneficial to the production of Co(IV). This work provides novel guidance for constructing piezoelectricity assisted high-valent cobalt oxo species to treat organic pollutants in environmental remediation. [ABSTRACT FROM AUTHOR]