School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland; Grupo de Investigación en Remediación Ambiental y Biocatálisis (GIRAB), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquía UdeA, Calle 70 No. 52-21, Medellín, Colombia.
School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland.
Water Res. 2019 Oct 15;163:114894. doi: 10.1016/j.watres.2019.114894. Epub 2019 Jul 22.
This work presents a kinetic analysis of the exogenous photo-induced disinfection of E. coli in natural waters. Herein, the inactivation of bacteria by light and photo-generated transient species, i.e., hydroxyl radical (HO), excited triplet states of organic matter (CDOM*) and singlet oxygen (O), was studied. It was found that the exogenous disinfection of E. coli proceeds through a lag time, followed by an exponential phase triggered by photo-generated HO, O and CDOM*. Also, we report that the concentration increased of transient species (and especially HO) precursors decreased the lag times of bacteria inactivation. Due to the limitations of the competition kinetics methodology to include the lag phase, an alternative strategy to study the interaction between E. coli and photo-generated transient species was proposed, considering the log-linear pseudo-first order rate constants and lag-times. On this basis and by using APEX software, a full kinetic analysis of exogenous bacterial inactivation, taking into account both lag-time and exponential decay, was developed. This approach provided insights into the conditions that could make exogenous inactivation competitive with the endogenous process for the E. coli inactivation in natural sunlit waters. Hence, this research contributes to the understanding of fundamental kinetic aspects of photoinduced bacterial inactivation, which is the basis for light-assisted processes such as the solar disinfection (SODIS).
本工作对天然水中外源光诱导大肠杆菌消毒的动力学进行了分析。本文研究了光和光生瞬变物质（即羟基自由基 (HO)、有机物质的激发三重态 (CDOM*)和单线态氧 (O)）对细菌的灭活作用。研究发现，外源大肠杆菌的消毒过程经历一个潜伏期，随后由光生 HO、O 和 CDOM* 引发指数阶段。此外，我们还报告称，瞬变物质（尤其是 HO）前体浓度的增加会降低细菌失活动力学的潜伏期。由于竞争动力学方法的局限性，无法包括潜伏期，因此提出了一种替代策略来研究大肠杆菌与光生瞬变物质之间的相互作用，考虑到对数线性拟一级速率常数和潜伏期。在此基础上，并使用 APEX 软件，开发了一种完整的外源细菌失活动力学分析方法，同时考虑了潜伏期和指数衰减。该方法深入了解了使外源失活动力学与天然太阳光照水中的内源性过程竞争的条件。因此，本研究有助于理解光诱导细菌失活动力学的基本动力学方面，这是光辅助过程（如太阳能消毒 (SODIS)）的基础。
