采用密度泛函的理论(Density Functional Theory，DFT)，对零价铁酸性条件下降解甲硝唑机理开展研究. 对零价铁酸性条件下催化降解甲硝唑每一步的反应物质及可能的生成物作了理论计算并分析实验数据，验证所提出机理的可靠性. 最后计算了溶剂效应对反应的影响. 结果表明，零价铁在酸性条件下提供电子给反应体系，破坏共轭效应，增加反应体系的活性，为取代反应提供可能性；溶剂水存在的情况下有利于降解反应的发生.
Once antibiotics enter the environment, there will be a series of biological transformation process to eliminate them, such as hydrolysis, photolysis, biodegradation. In the laboratory, iron nanoparticles are proved better to degrade metronidazole. Numerous experimental studies have improved the efficiency of metronidazole degradation, few theoretical studies focused on the mechanism. This work investigated the degradation mechanism of metronidazole with density functional theory (DFT). Experimental results suggest a stepwise process catalyzed by Fe nano particles, finally the reactant nitro was catalyzed to amino through a series of reactions. Each intermediate product was simulated, the two oxygen atoms of nitro group are gradually replaced by hydrogens. The solvent effect is also considered. Calculation results show that the irons provide electrons, thus increasing the activity of the system, and the solvent promoted the reaction.