Pharmaceutically active compounds (PhACs), such as sulfamethoxazole (SMX), 17β-estradiol (EST), and carbamazepine (CBZ), are found virtually everywhere in hospital effluent and are resistant to the treatment procedures that are typically used. These substances can be degraded by using advanced oxidation techniques such as photocatalysis; nevertheless, the performance of these methods in continuous mode and in a real wastewater matrix has not been sufficiently explored. As a result, an iron-modified aluminum-doped zinc oxide (Al-ZnO/Fe) based- photocatalyst was utilized in this research in order to simultaneously degrade SMX, EST, and CBZ. Due to the large band gap, ZnO was chosen to serve as the base material of the photocatalyst. The recombination of electrons (e^-) and holes (h⁺) is one of the fundamental flaws of ZnO-based photocatalysts. Aluminum (Al), which is readily available and inexpensive, was used as a doping agent in order to prevent the recombination of e^- and h⁺. Aluminum stops the excited e^- from going back to the valence band and leaping back in. A modification involving iron (Fe) has been carried out in order to assist the separation of the photocatalyst from the aqueous medium by utilizing the magnetic characteristics of the photocatalyst. The removal of SMX, EST, and CBZ was investigated at a hydraulic retention time (HRT) of 2 h, 3h, and 4 h. At the HRT of 4 h, the SMX, CBZ, and EST removal in DI water was 91.8 ± 2.48%, 90.66 ± 2.01%, and 90.2 ± 1.48%, respectively; in tap water, it was 70.56 ± 2.15%, 66.06 ± 1.01%, and 63.83 ± 1.89%, respectively; in hospital wastewater, it was 52.56 ± 0.37%, 11.63 ± 2.06%, and 11.23 ± 2.61%, respectively. The presence of interfering ions, COD, and suspended solids was the primary reason for the lower removal in the case of real wastewater.

Abhradeep Majumder

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