Efficient photothermal persulfate activation for rapid removal of antibiotics by heat-promoted Co3+ to Co2+ conversion on Bi12CoO20 photocatalyst

Efficient removal of ofloxacin (OFX) is achieved in the Bi12CoO20/persulfate (PS) photothermal system. Over 80 % of the pollutant (10–200 ppm) is degraded within 1 h reaction and remarkably the degradation rate of 10 ppm OFX reaches 4.6 times higher than that of P25. The superior performance can be attributed to the synergistically photothermal PS activation. Heat changes to surface Co3+ to Co2+ on Bi12CoO20, and lower the activation energy of PS while light excites electrons to reduce PS to yield SO4•- when surface Co2+ forms. By retaining the active sites (surface Co2+) for PS activation, the photothermal activation rate of PS enhances to 0.122 min−1, 24.4 times higher than that (0.005 min−1) without photothermal effect. The current research provides insights into the PS photothermal activation system and aids in the development of a more efficient PS activation method for antibiotics degradation in the future.