Biogenic Palladium Enhances Diatrizoate Removal from Hospital Wastewater in a Microbial Electrolysis Cell

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• 作者：Bart De Gusseme ; Tom Hennebel ; Lynn Vanhaecke ; Maarten Soetaert ; Joachim Desloover ; Klaas Wille ; Kim Verbeken ; Willy Verstraete ; Nico Boon
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：July 1, 2011
• 年：2011
• 卷：45
• 期：13
• 页码：5737-5745
• 全文大小：852K
• 年卷期：v.45,no.13(July 1, 2011)
• ISSN：1520-5851

文摘

To decrease the load of pharmaceuticals to the environment, decentralized wastewater treatment has been proposed for important point-sources such as hospitals. In this study, a microbial electrolysis cell (MEC) was used for the dehalogenation of the iodinated X-ray contrast medium diatrizoate. The presence of biogenic palladium nanoparticles (bio-Pd) in the cathode significantly enhanced diatrizoate removal by direct electrochemical reduction and by reductive catalysis using the H₂ gas produced at the cathode of the MEC. Complete deiodination of 3.3 渭M (2 mg L^鈥?) diatrizoate from a synthetic medium was achieved after 24 h of recirculation at an applied voltage of 鈭?.4 V. An equimolar amount of the deiodinated metabolite 3,5-diacetamidobenzoate (DAB) was detected. Higher cell voltages increased the dehalogenation rates, resulting in a complete removal after 2 h at 鈭?.8 V. At this cell voltage, the MEC was also able to remove 85% of diatrizoate from hospital effluent containing 0.5 渭M (292 渭g L^鈥?), after 24 h of recirculation. Complete removal was obtained when the effluent was continuously fed at a volumetric loading rate of 204 mg diatrizoate m^鈥? total cathodic compartment (TCC) day^鈥? to the MEC with a hydraulic retention time of 8 h. At 鈭?.8 V, the MEC system could also eliminate 54% of diatrizoate from spiked urine during a 24 h recirculation experiment. The final product DAB was demonstrated to be removable by nitrifying biomass, which suggests that the combination of a MEC and bio-Pd in its cathode offers potential to dehalogenate pharmaceuticals, and to significantly lower the environmental burden of hospital waste streams.