Cobalt-substituted porous calcium copper titanate electrodes for paracetamol degradation by an electro-oxidation/peroxymonosulfate system

Developing cobalt-substituted perovskite electroactive membranes with an efficient Co/Cu combination mode is an important environmental challenge for removing drugs via peroxymonosulfate (PMS) activation. In this work, cobalt (Co)-substituted calcium copper titaniate(Co-CCTO) was synthesized with an easy ball milling process and used as an anode in electro-oxidation in the presence of PMS for paracetamol degradation. The Co-CCTO anode with a Co ratio of 0.5 showed the highest removal efficiency (100 % of 10 ppm paracetamol after 180 min) due to the increase of the active sites and the appearance of the Co2+/ Co3+ cycle that accelerates the charge transfer with Co incorporation into the lattice. Scavenger experiments showed that sulfate radicals (SO4̇−), oxygen radicals (O2̇-), hydroxyl radicals (̇OH), and singlet oxygen (1O2) were generated in the electro-oxidation-PMS reaction system and that SO4̇−, 1O2, and O2̇- were the dominant active radicals. The toxicity tests with Vibrio fischeri confirmed paracetamol mineralization and decomposition and the elimination of harmful by-products. It is crucial to explore the substitution of CCTO with different metal dopants in order to optimize the membrane performance and overcome the limitations associated with cobalt substitution.