Comparison of Photocatalytic Performance of Sr0.9La0.1TiO3 and Sr0.25Ca0.25Na0.25Pr0.25TiO3 Towards Metoprolol and Pindolol Photodegradation

Abstract

The photocatalytic performance of Sr0.9La0.1TiO3 and Sr0.25Ca0.25Na0.25Pr0.25TiO3 perovskite–based catalysts were studied under different radiation types (simulated solar, LED, and UV radiation) for removal of metoprolol and pindolol. The results showed that both materials effectively removed metoprolol and pindolol, with the highest degradation efficiency observed under UV radiation. The degradation efficiency of metoprolol went up to 30% using Sr0.9La0.1TiO3 and Sr0.25Ca0.25Na0.25Pr0.25TiO3 using all mentioned radiation types. Pindolol was degraded more efficiently, using Sr0.9La0.1TiO3 68%, 94%, and 100% of pindolol was degraded after 240 min, under SSI, UV-LED, and UV irradiation. Using Sr0.25Ca0.25Na0.25Pr0.25TiO3, degradation efficiency was 65%, 84%, and 93%, under SSI, UV-LED, and UV irradiation, respectively. The chemical oxygen demand showed that these materials were highly efficient in mineralizing metoprolol and pindolol as well as their intermediates. The mechanisms behind the degradation of metoprolol using perovskite catalysts are complex. Still, ongoing research has indicated that the degradation mechanism occurs through hydroxylation of the aromatic ring or side chains. A similar degradation pathway is suggested for the degradation of pindolol, including opening an indol ring at the nitrogen atom site.