Abstract Microwave has been extensively applied to inactivate microorganisms in liquids, food, and surfaces. However, energy efficiency is a limiting factor for the environmental application. The utilization pathway and energy efficiency of the microwave in different media have not been investigated. In this study, the inactivation performance, energy utilization, and bactericidal mechanisms for microwave-irradiated airborne and waterborne Escherichia coli were compared. A Beer-Lambert law-based model was also developed and validated to compare the inactivation performance in different phases. Microwave had greater inactivation effect on airborne bacteria than waterborne bacteria. The inactivation rate constant for airborne E. coli (0.29 s−1) was nearly 20 times higher than that of waterborne species (0.014 s−1). Most of the absorbed microwave energy (92.3%) was converted to increase water temperature instead of inactivating the waterborne bacteria, because the microwave photons were easily absorbed by water molecules. By contrast, 45.4% of the absorbed energy could disinfect the airborne bacteria. Finally, the required energies for 1-log inactivation were calculated as 2.3 J and 116.9 J per log-inactivation for airborne and waterborne E. coli, respectively. The airborne and waterborne E. coli samples showed distinct microwave inactivation mechanisms. Waterborne E. coli disinfection was primarily due to thermal effect, while the non-thermal effect was the major mechanism for airborne E. coli inactivation.

中文翻译：

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使用基于微波的技术进行空气消毒：与水性消毒相比，节能且灭活机制不同

摘要 微波已广泛应用于灭活液体、食物和表面的微生物。然而，能源效率是环境应用的限制因素。微波在不同介质中的利用途径和能量效率尚未研究。本研究比较了微波辐照空气中和水源性大肠杆菌的灭活性能、能量利用和杀菌机制。还开发并验证了基于 Beer-Lambert 定律的模型，以比较不同阶段的灭活性能。微波对空气传播细菌的灭活作用大于水传播细菌。空气传播的大肠杆菌（0.29 s-1）的灭活速率常数比水性物种（0.014 s-1）高近 20 倍。大部分吸收的微波能量（92.3%）被转化为提高水温而不是灭活水生细菌，因为微波光子很容易被水分子吸收。相比之下，45.4% 的吸收能量可以对空气中的细菌进行消毒。最后，对于空气传播和水传播的大肠杆菌，1-log 灭活所需的能量分别计算为 2.3 J 和 116.9 J 每次对数灭活。空气传播和水传播的大肠杆菌样本显示出不同的微波灭活机制。水性大肠杆菌消毒主要是由于热效应，而非热效应是空气传播大肠杆菌灭活的主要机制。因为微波光子很容易被水分子吸收。相比之下，45.4% 的吸收能量可以对空气中的细菌进行消毒。最后，对于空气传播和水传播的大肠杆菌，1-log 灭活所需的能量分别计算为 2.3 J 和 116.9 J 每次对数灭活。空气传播和水传播的大肠杆菌样本显示出不同的微波灭活机制。水性大肠杆菌消毒主要是由于热效应，而非热效应是空气传播大肠杆菌灭活的主要机制。因为微波光子很容易被水分子吸收。相比之下，45.4% 的吸收能量可以对空气中的细菌进行消毒。最后，对于空气传播和水传播的大肠杆菌，1-log 灭活所需的能量分别计算为 2.3 J 和 116.9 J 每次对数灭活。空气传播和水传播的大肠杆菌样本显示出不同的微波灭活机制。水性大肠杆菌消毒主要是由于热效应，而非热效应是空气传播大肠杆菌灭活的主要机制。空气传播和水传播的大肠杆菌样本显示出不同的微波灭活机制。水性大肠杆菌消毒主要是由于热效应，而非热效应是空气传播大肠杆菌灭活的主要机制。空气传播和水传播的大肠杆菌样本显示出不同的微波灭活机制。水性大肠杆菌消毒主要是由于热效应，而非热效应是空气传播大肠杆菌灭活的主要机制。