National Science Foundation Engineering Research Center for Reinventing the Nation's Urban Water Infrastructure (ReNUWIt) and Department of Civil & Environmental Engineering , University of California at Berkeley , Berkeley , California 94720 , United States.
Department of Earth Sciences, Geochemistry, Faculty of Geosciences , Utrecht University , Utrecht 3508TA , The Netherlands.
Environ Sci Technol. 2018 Sep 18;52(18):10728-10736. doi: 10.1021/acs.est.8b03304. Epub 2018 Aug 30.
Urban stormwater, municipal wastewater effluent, and agricultural runoff contain trace amounts of organic contaminants that can compromise water quality. To provide a passive, low-cost means of oxidizing substituted phenols, aromatic amines, and other electron-rich organic compounds during infiltration of contaminated waters, we coated sand with manganese oxide using a new approach involving the room-temperature oxidation of Mn with permanganate. Manganese oxide-coated sand effectively oxidized bisphenol A under typical infiltration conditions and sustained reactivity longer than previously described geomedia. Because geomedia reactivity decreased after extended operation, chlorine was evaluated for use as an in situ geomedia regenerant. Geomedia regenerated by HOCl demonstrated similar reactivity and longevity to that of virgin geomedia. Chemical analyses indicated that the average manganese oxidation state of the coatings decreased as the geomedia passivated. X-ray absorption spectroscopy and X-ray diffraction showed that the reactive virgin and regenerated geomedia coatings had nanocrystalline manganese oxide structures, whereas the failed geomedia coating exhibited greater crystallinity and resembled cryptomelane. These results suggest that it is possible to regenerate the oxidative capacity of manganese oxide-coated sands without excavating stormwater infiltration systems. These results also suggest that manganese oxide geomedia may be a cost-effective means of treating urban stormwater and other contaminated waters.
城市雨水、城市污水和农业径流中含有痕量的有机污染物，这些污染物会影响水质。为了在受污染的水渗透过程中提供一种被动的、低成本的氧化取代酚、芳香胺和其他富电子有机化合物的方法，我们使用一种新方法，在室温下用高锰酸盐氧化 Mn，用 MnO2 对砂进行了涂层处理。MnO2 涂层砂在典型的渗透条件下有效地氧化了双酚 A，并且比以前描述的地质介质具有更长的反应活性。由于长时间运行后地质介质的反应活性下降，因此评估了次氯酸（HOCl）作为原位地质介质再生剂的使用。用 HOCl 再生的地质介质表现出与原始地质介质相似的反应活性和寿命。化学分析表明，随着地质介质的钝化，涂层的平均锰氧化态降低。X 射线吸收光谱和 X 射线衍射表明，反应性原始和再生的地质介质涂层具有纳米晶 MnO2 结构，而失效的地质介质涂层表现出更高的结晶度，类似于隐钾锰矿。这些结果表明，有可能在不挖掘雨水渗透系统的情况下，再生 MnO2 涂层砂的氧化能力。这些结果还表明，MnO2 地质介质可能是处理城市雨水和其他受污染水的一种具有成本效益的方法。
