CaCu₃Ti₄O₁₂, an efficient catalyst for ibuprofen removal by activation of peroxymonosulfate under visible-light irradiation

Contamination of waters by pharmaceuticals is a major health issue. Therefore, there is a need for efficient techniques to remove pharmaceutical pollutants. Here, a photo-assisted fenton-like method based on sulfate radicals was tested using CaCu₃Ti₄O₁₂ with different morphologies as catalyst. Sintering of CaCu₃Ti₄O₁₂ at 775 °C for 6 h produced cubic structures with sizes from 2 to 5 μm, whereas sintering for 14 h produced microfibers, according to scanning electron microscopy. The highest electron paramagnetic resonance signal was observed for 6-h sintering. We evaluated the catalytic efficiency of CaCu₃Ti₄O₁₂ for ibuprofen degradation with peroxymonosulfate under visible light. Results show that CaCu₃Ti₄O₁₂ and 0.5 mM peroxymonosulfate under visible-light irradiation induced 91.8% removal of ibuprofen in 60 min. The Cu⁺ vacancy on the surface of CaCu₃Ti₄O₁₂ is essential to activate the sulfate radicals by forming a Cu⁺–Cu²⁺ redox couple, which led to the rapid and efficient removal of ibuprofen.