Spinel CoFe2O4 nanoparticles-catalyzed advanced oxidation processes for oxytetracycline degradation: Understanding the influence of temperature and developing photothermal countermeasure

In the treatment of antibiotic-containing wastewater, the influence of temperature on heterogeneous advanced oxidation processes (AOPs) efficiency is often overlooked, hindering practical guidance for cold conditions. Herein, spinel CoFe 2 O 4 nanoparticles were studied as catalysts to activate HCO 3 − /H 2 O 2 (BAP), persulfate (PMS) and peracetic acid (PAA) for oxytetracycline (OTC) degradation at different temperatures, respectively. The apparent activation energy of OTC degradation in CoFe 2 O 4 /PMS, CoFe 2 O 4 /BAP and CoFe 2 O 4 /PAA system was 28.18, 21.02 and 41.17 kJ mol −1 , respectively, showing temperature dependent feature. Three CoFe 2 O 4 -catalyzed AOPs' activity was proportional to temperature. At 5 ± 1.5 °C and 15 ± 1.5 °C, three CoFe 2 O 4 -catalyzed AOPs' efficiency in OTC degradation was unsatisfactory. Under visible light LED irradiation, three CoFe 2 O 4 -catalyzed AOPs' activity for OTC degradation at low temperatures was significantly improved, through making use the photothermal property of spinel CoFe 2 O 4 to rise temperature and accelerate reactions. The degradation of OTC in three CoFe 2 O 4 -catalyzed AOPs was initiated by typical reactive species that be mainly produced from CoFe 2 O 4 activating BAP (•OH, 1 O 2 , O 2 •- , CO 3 •- ), PMS (O 2 •- , •OH, 1 O 2 , SO 4 •- ) or PAA ( 1 O 2 , •OH).