摘要
      过硫酸盐去除抗生素抗性细菌（ARB）和抗生素抗性基因（ARGs）的机制归因于活性氧（ROS）的产生。然而，过硫酸盐体系中pH值降低对ARB和ARGs去除的潜在贡献很少被报道。本文研究了纳米级零价铁活化过硫酸盐（nZVI/PS）去除ARB和ARGs的效率和机理。结果表明，nZVI/20 mM PS可在5分钟内完全灭活ARB（2×108 CFU/mL），对sul1和intI1的去除率分别为98.95%和99.64%。机理研究表明，羟基自由基是nZVI/PS去除ARB和ARGs的主要活性氧。重要的是，nZVI/PS系统的pH值大大降低，甚至在nZVI/20mM PS系统中降至2.9。令人印象深刻的是，当细菌悬浮液的pH调节至2.9时，30分钟内ARB、sul1和intI1的去除率分别为60.33%、73.76%和71.51%。进一步的激发发射矩阵分析证实，降低的pH值有助于ARB损伤。上述关于pH影响的结果表明，nZVI/PS体系pH的降低也对ARB和ARGs的去除做出了重要贡献。
Abstract
The mechanism of removing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) by persulfate was attributed to the generation of reactive oxygen species (ROS). However, the potential contribution of decreased pH in persulfate system to ARB and ARGs removal has rarely been reported. Here, the efficiency and mechanism of removing ARB and ARGs by nanoscale zero-valent iron activated persulfate (nZVI/PS) were investigated. Results showed that the ARB (2 × 108 CFU/mL) could be completely inactivated within 5 min, and the removal efficiencies of sul1 and intI1 were 98.95% and 99.64% by nZVI/20 mM PS, respectively. Investigation of mechanism revealed that hydroxyl radicals was the dominant ROS of nZVI/PS in removing ARB and ARGs. Importantly, the pH of nZVI/PS system was greatly decreased, even to 2.9 in nZVI/20 mM PS system. Impressively, when the pH of the bacterial suspension was adjusted to 2.9, the removal efficiency of ARB, sul1 and intI1 were 60.33%, 73.76% and 71.51% within 30 min, respectively. Further excitation-emission-matrix analysis confirmed that decreased pH contributed to ARB damage. The above results on the effect of pH indicated that the decreased pH of nZVI/PS system also made an important contribution for the removal of ARB and ARGs.

https://www.sciencedirect.com/science/article/abs/pii/S030438942300626X