Solar Photocatalysis for Degradation of Pharmaceuticals in Hospital Wastewater: Influence of the Type of Catalyst, Aqueous Matrix, and Toxicity Evaluation

In this work, solar photocatalytic degradation of the drug mixture atenolol (ATL), acetaminophen (ACP), and sulfamethoxazole (SMX) in distilled water, tap water, and hospital wastewater was evaluated. The photocatalytic activity of two commercial TiO2-based catalysts, Degussa P25 and KronoClean 7000, was studied at different catalyst amounts, under simulated and natural solar irradiation for the solution of 10 mg L-1 initial concentration of each drug. The results showed complete degradation of the mixture and abatement of 70% of the initial TOC concentration in distilled water with Degussa P25 (1.0 g L-1) using both radiation sources at 400 kJ m(-2) of the UV accumulated energy. Thus, to evaluate the matrix effect in the process, the degradation was carried out in hospital wastewater spiked with the drug mixture. Complete degradation of ACP and ATL and 85% of SMX elimination was reached in hospital wastewater, but only 18.1% of the initial TOC reduction was achieved using Degussa P25 catalyst under natural solar radiation at 400 kJ m(-2) of accumulated UV energy. Additionally, the process was evaluated in a 20 L semi-pilot plant where degradation near 90% for all drugs was reached in tap water using 0.5 g L-1 of Degussa P25, obtaining a 51.6% of TOC abatement at 38.9 kJ L-1 of accumulated UV energy. Finally, the effluent toxicity during the degradation of the pharmaceuticals in hospital wastewater was evaluated, finding that the natural solar-mediated photocatalysis using TiO2 Degussa P25 is an effective process to obtain a non-toxic effluent.

Automated summary

This work evaluated the solar photocatalytic degradation of a drug mixture in different environments and studied the photocatalytic activity of two commercial catalysts. The results showed that solar photocatalysis can effectively degrade the drug mixture under suitable conditions.