Matrix Effects on the Degradation of Gemfibrozil, Hydrochlorothiazide, and Naproxen by Heterogeneous Photocatalysis

The degradation of a pharmaceutical mixture (gemfibrozil, hydrochlorothiazide and naproxen) by TiO2/UV-A in different aqueous matrices was evaluated. The matrix components affected the operational conditions, rate constants, and removal efficiency of the pharmaceuticals, as well as toxicity. For sewage treatment plant effluent, a TiO2 concentration three-fold higher (450 mg L−1) and an irradiation time 1.5-3 times longer were required to reach the same efficiency of degradation as the pharmaceuticals in deionized water and surface water matrices. An improvement in the rate constants and the removal efficiency of the pharmaceuticals was achieved by adding 6 mg L−1 of H2O2 and 150 mg L−1 of TiO2 in deionized water and surface water, but not in the sewage treatment plant effluent, due to the coupling of 450 mg L−1 of TiO2 and 50-200 mg L−1 of H2O2. Overall, TiO2/UV-A efficiently degraded all compounds, but an additional step is needed for the removal of residual toxicity.

本研究评估了二氧化钛/紫外A（TiO2/UV-A）体系对吉非贝齐、氢氯噻嗪及萘普生组成的药物混合体系在不同水基质中的降解效果。水基质的组成成分会影响该工艺的运行条件、药物的降解速率常数与去除效率，同时也会影响体系毒性。相较于去离子水与地表水基质中的药物降解效果，要达到相同的降解效率，污水处理厂出水体系需要将二氧化钛浓度提升至原浓度的3倍（450 mg L−1），且辐照时间需延长1.5~3倍。在去离子水与地表水基质中，投加6 mg L−1过氧化氢（H2O2）与150 mg L−1二氧化钛可提升药物的降解速率常数与去除效率，但在污水处理厂出水体系中未观察到该改善效果，这是由于该体系采用了450 mg L−1二氧化钛与50~200 mg L−1过氧化氢的复配体系。总体而言，二氧化钛/紫外A（TiO2/UV-A）体系可高效降解所有目标化合物，但仍需额外工艺步骤以去除体系残留毒性。