Photocatalytic degradation of β-blockers by using immobilized titania/silica on glass slides

• The immobilized photocatalyst on the glass slides was prepared.
• Two types of commercial nanoparticles of titanium dioxide were compared.
• Evonik Degussa P25 showed better photocatalytic activity than P90.
• All five β-blockers were completely eliminated during photocatalytic treatment.
• Intermediates were identified mostly as hydroxylation or cleavage products.

Photocatalytic degradation of five β-blockers (acebutolol, atenolol, metoprolol, nadolol and propranolol) was investigated in aqueous media using immobilized TiO2 as a photocatalyst. The analyzed parameters were pharmaceutical removal and non purgeable organic carbon. Two different types of photocatalyst incorporated in sol–gel matrix were compared; P25 exhibited a higher photocatalytic activity compared to P90 (both from Evonik Degussa). Besides, optimal photocatalyst concentration and light intensity were determined. According to the results obtained, after 120 min of treatment a complete removal was achieved for all compounds (initial concentration 25 mg/L) using P25. After 240 min of irradiation a mineralization degree ranged from 75% for acebutolol to 92% for propranolol. A longer illumination time was needed for complete removal of β-blockers in river water. Main intermediate compounds were identified by high performance liquid chromatography coupled to mass spectrometry (HPLC–MS/MS) technique.

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