Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843-3136, United States.
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, Georgia 30329, United States.
Environ Sci Technol. 2021 Oct 5;55(19):13198-13208. doi: 10.1021/acs.est.0c04438. Epub 2021 Sep 21.
Virus destabilization and inactivation are critical considerations in providing safe drinking water. We demonstrate that iron electrocoagulation simultaneously removed (via sweep flocculation) and inactivated a non-enveloped virus surrogate (MS2 bacteriophage) under slightly acidic conditions, resulting in highly effective virus control (e.g., 5-logs at 20 mg Fe/L and pH 6.4 in 30 min). Electrocoagulation simultaneously generated HO and Fe(II) that can potentially trigger electro-Fenton reactions to produce reactive oxygen species such as OH and high valent oxoiron(IV) that are capable of inactivating viruses. To date, viral attenuation during water treatment has been largely probed by evaluating infective virions (as plaque forming units) or genomic damage (via the quantitative polymerase chain reaction). In addition to these existing means of assessing virus attenuation, a novel technique of correlating transmission electron micrographs of electrocoagulated MS2 with their computationally altered three-dimensional electron density maps was developed to provide direct visual evidence of capsid morphological damages during electrocoagulation. The majority of coliphages lost at least 10-60% of the capsid protein missing a minimum of one of the 5-fold and two of 3- and 2-fold regions upon electrocoagulation, revealing substantial localized capsid deformation. Attenuated total reflectance-Fourier transform infrared spectroscopy revealed potential oxidation of viral coat proteins and modification of their secondary structures that were attributed to reactive oxygen species. Iron electrocoagulation simultaneously disinfects and coagulates non-enveloped viruses (unlike conventional coagulation), adding to the robustness of multiple barriers necessary for public health protection and appears to be a promising technology for small-scale distributed water treatment.
病毒失稳和灭活是提供安全饮用水的关键考虑因素。我们证明，在略酸性条件下，铁电絮凝通过扫流絮凝同时去除（去除）和灭活非包膜病毒（MS2 噬菌体），从而实现高效的病毒控制（例如，在 20mg Fe/L 和 pH 6.4 下 30 分钟内达到 5 个对数级）。电絮凝同时产生 HO 和 Fe(II)，这可能会引发电芬顿反应，产生具有灭活病毒能力的活性氧物质，如 OH 和高价氧代铁（IV）。迄今为止，水处理过程中的病毒衰减主要通过评估感染性病毒粒子（作为噬菌斑形成单位）或基因组损伤（通过定量聚合酶链反应）来研究。除了这些现有的评估病毒衰减的方法之外，还开发了一种将电絮凝 MS2 的透射电子显微镜图像与它们经过计算改变的三维电子密度图相关联的新技术，以提供电絮凝过程中衣壳形态损伤的直接直观证据。大多数噬菌体在电絮凝时至少损失了 10-60%的衣壳蛋白，缺失了 5 倍区至少一个、3 倍区和 2 倍区各两个，表明衣壳发生了实质性的局部变形。衰减全反射傅里叶变换红外光谱揭示了病毒外壳蛋白的潜在氧化和它们的二级结构的修饰，这归因于活性氧物质。铁电絮凝通过扫流絮凝同时消毒和凝结非包膜病毒（与传统的凝结不同），增加了公共卫生保护所需的多个屏障的稳健性，并且似乎是一种有前途的小规模分布式水处理技术。
