Wang Junyue, Kim Juhee, Li Jiaqi, Krall Caroline, Sharma Virender K, Ashley Daniel C, Huang Ching-Hua
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
School of Public Health, Texas A&M University, College Station, Texas 77843, United States.
Environ Sci Technol. 2024 Sep 14;58(38):17157-67. doi: 10.1021/acs.est.4c05234.
High-valent iron (Fe(IV/V/VI)) has been widely applied in water decontamination. However, common Fe(II)-activating oxidants including hydrogen peroxide (HO) and persulfate react slowly with Fe(II) and exhibit low selectivity for Fe(IV) production due to the cogeneration of radicals. Herein, we report peroxyacids (POAs; R-C(O)OOH) that can react with Fe(II) more than 3 orders of magnitude faster than HO, with high selectivity for Fe(IV) generation. Rapid degradation of bisphenol A (BPA, an endocrine disruptor) was achieved by the combination of Fe(II) with performic acid (PFA), peracetic acid (PAA), or perpropionic acid (PPA) within one second. Experiments with phenyl methyl sulfoxide (PMSO) and -butyl alcohol (TBA) revealed Fe(IV) as the major reactive species in all three Fe(II)-POA systems, with a minor contribution of radicals (i.e., OH and R-C(O)O). To understand the exceptionally high reactivity of POAs, a detailed computational comparison among the Fenton-like reactions with step-by-step thermodynamic evaluation was conducted. The high reactivity is attributed to the lower energy barriers for O-O bond cleavage, which is determined as the rate-limiting step for the Fenton-like reactions, and the thermodynamically favorable bidentate binding pathway of POA with iron. Overall, this study advances knowledge on POAs as novel Fenton-like reagents and sheds light on computational chemistry for these systems.
高价铁（Fe(IV/V/VI)）已广泛应用于水净化。然而，常见的Fe(II)活化氧化剂，包括过氧化氢（HO）和过硫酸盐，与Fe(II)反应缓慢，并且由于自由基的同时产生，对Fe(IV)的生成表现出低选择性。在此，我们报道了过氧酸（POAs；R-C(O)OOH），其与Fe(II)的反应速度比HO快3个数量级以上，对Fe(IV)的生成具有高选择性。通过将Fe(II)与过甲酸（PFA）、过乙酸（PAA）或过丙酸（PPA）组合，在一秒内实现了双酚A（BPA，一种内分泌干扰物）的快速降解。使用苯甲基亚砜（PMSO）和叔丁醇（TBA）的实验表明，在所有三个Fe(II)-POA体系中，Fe(IV)是主要的反应物种，自由基（即OH和R-C(O)O）的贡献较小。为了理解POAs异常高的反应活性，我们进行了详细的计算比较，并进行了逐步热力学评估的类芬顿反应。高反应活性归因于O-O键断裂的能量障碍较低，这被确定为类芬顿反应的限速步骤，以及POA与铁的热力学有利的双齿结合途径。总体而言，本研究推进了关于POAs作为新型类芬顿试剂的知识，并为这些体系的计算化学提供了启示。
