Publication: Photocatalytic degradation of selected pharmaceutical compounds in municipal wastewater treatment plant using solar fe2o3-tio2 catalysts
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Date
2023-10-01
Authors
Omar Fawzi Suleiman Khasawneh
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Abstract
Pharmaceutical compounds (PhACs) have become significant water pollutants due to their persistence and adverse effects on human health and the aquatic environment. This study aimed to investigate the occurrence of specific PhACs (ketoprofen, diclofenac, atenolol, and carbamazepine) in a wastewater treatment plant (M-WWTP) in Penang. Additionally, the photocatalytic degradation of these compounds using two different photocatalysts (TiO2 P25 and Fe2O3-TiO2) was examined at lab and pilot-plant scales. A validated HPLC-UV method allowed for detection and quantification of the PhACs in the M-WWTP. Results showed concentration ranges of PhACs in influent samples from below the detection limit to 1469 ng/L, and in effluent samples from below the detection limit to 761 ng/L. The highest removal efficiency was observed for ketoprofen (75%), followed by atenolol (71.5%), diclofenac (52.6%), and carbamazepine (48.1%). Average daily mass loads, emissions, and estimated consumption of PhACs varied compared to other regions. The ecological risk assessment indicated a low to moderate potential risk, emphasizing the importance of risk management and prioritization. Under lab-scale conditions, the selected compounds showed removal efficiencies ranging from 87% to 97%, with diclofenac exhibiting the highest rates, followed by atenolol and carbamazepine. Fe2O3-TiO2 displayed higher activity in degrading the target pollutants compared to TiO2 P25, with an optimal catalyst concentration of 0.2 g/L. At the pilot-plant scale, Fe2O3-TiO2
achieved removal efficiencies ranging from 79% to 88.8%, while TiO2 P25 exhibited rates between 59% and 81.7% for all target pharmaceuticals. The prepared photocatalyst demonstrated optimal reaction rates for atenolol, diclofenac, and carbamazepine at concentrations of 0.2 g/L. During the photocatalytic degradation, a maximum reduction of 33% in TOC content was observed after 5 hours. Cation concentration levels remained unaffected throughout the photodegradation process. The reusability of both photocatalysts showed significant performance deterioration after five cycles, with less than 50% efficiency. The approximate cost for solar-CPCR pilot-plant trials was 0.65 MYR per m3 with TiO2 P25 and 1.47 MYR per m3 with Fe2O3-TiO2.