Fabrication of Sb₂O₃/PbO photocatalyst for the UV/PMS assisted degradation of carbamazepine from synthetic wastewater

Photocatalytic degradation of carbamazepine (CBZ) was investigated by hydrothermally synthesized antimony trioxide (Sb₂O₃)/lead oxide (PbO) photocatalyst. The photocatalyst synthesized with different ratio of Sb₂O₃ and PbO viz. 1:1, 2:1, 3:1, 1:2, and 1:3. Photocatalyst with 3:1 ratio of Sb₂O₃ and PbO showed the best photocatalytic activity towards CBZ. Transmission electron microscopy (TEM) analysis suggested that the particle size increased by increasing PbO ratio in the catalyst. It was observed that Sb₂O₃ synthesis with PbO showed less band gap energy in comparison to Sb₂O₃. The Brunauer–Emmer–Teller (BET) surface area of the Sb₂O₃/PbO (3:1) was determined to be 4.78 m² g⁻¹. In absence of catalyst, very low degradation of CBZ was achieved, while significant enhancement in CBZ degradation was observed in presence of the synthesized catalyst. CBZ degradation followed the pseudo first-order kinetics with rate constant of 0.016 min⁻¹. Increased degradation rate was recorded when peroxymonosulfate (PMS) was used with UV/Sb₂O₃/PbO. Active species trapping experiment revealed that in CBZ degradation, ^[rad]O₂ ^– radical produced by synthesized catalysts played a major role. In presence of PMS, generation of SO₄ ^-∙ radical enhanced the catalytic activity of synthesized catalyst.