Insights into bromate reduction by Fe(II): Multiple radicals generation and carbamazepine oxidation
Insights into bromate reduction by Fe(II): Multiple radicals generation and carbamazepine oxidation
复制标题
DOI：
10.1016/j.cej.2021.133957
复制
发表时间：
2021-12
影响因子：
15.1
通讯作者：
Cong Pan;Libin Fu;Fenna Lide;Yaobin Ding;Chengjun Wang;Jia Huang;Shaobin Wang
中科院分区：
文献类型：
--
作者：
Cong Pan;Libin Fu;Fenna Lide;Yaobin Ding;Chengjun Wang;Jia Huang;Shaobin Wang
通过各种技术还原溴酸盐（BrO 3 −）已经得到了广泛的研究，而在这些过程中，BrO 3 −中的氧原子和溴原子的命运在很大程度上被忽略了。在这项研究中，通过电子自旋共振（ESR），激光闪光光解（LFP），苯酚探针和淬灭实验，研究了在各种条件下Fe（II）离子对BrO 3 −的还原。研究发现，Fe（II）离子还原BrO 3 −产生HO·、O2·−和活性溴物种（例如，Br·和Br 2·−）。HO·和O2·−是由BrO 3-及其还原中间体BrO 2-和BrO-中的一个或两个氧原子同时释放而产生的，而Br·和Br 2·−是由Fe（II）活化次溴酸并与生成的Br-反应而产生的。由于这些活性物种的形成，可有效降解卡马西平（CBZ）、布洛芬、苯酚、苯甲酸、扑热息痛、双酚a、4-氯苯酚、奥卡西平、双氯芬酸和磺胺甲恶唑等10种结构各异的有机污染物。采用液相色谱-质谱联用技术（LC-MS）对BrO 3 −/Fe（II）体系降解CBZ的中间产物进行了鉴定，并据此提出了CBZ降解的3条途径：羟基化/亚硝基化、缩环-胺裂解和溴化。该研究为溴酸盐还原及其对共存有机污染物转化的意义提供了新的基础性认识。
Reduction of bromate (BrO3−) by various technologies has been extensively investigated, while the fate of oxygen and bromine atoms in BrO3−in these processes has been largely ignored. In this study, reduction of BrO3−by Fe(II) ions was investigated under various conditions via electron spin resonance (ESR), laser flash photolysis (LFP), probe of phenol and quenching experiments. It was found that reduction of BrO3−by Fe(II) ions produced HO•, O2•−and reactive bromine species (eg., Br• and Br2•−). HO• and O2•−were generated from release of one/two oxygen atoms in BrO3−and its reduction intermediates (BrO2−and BrO−) at one time, while Br• and Br2•−were generated from activation of hypobromous acid by Fe(II) and reactions of HO• with formed Br−. Due to the formation of these reactive species, the tested ten organic pollutants with diverse structures can be efficiently degraded, which including carbamazepine (CBZ), ibuprofen, phenol, benzoic acid, paracetamol, bisphenol a, 4-chlorophenol, oxcarbazepine, diclofenac and sulfamethoxazole. CBZ degradation intermediates by BrO3−/Fe(II) system were specially identified by liquid chromatography (LC)-mass spectrometry (MS), and three pathways of hydroxylation/nitrosylation, ring contraction-amine cleavage and bromination for CBZ degradation were proposed accordingly. This study might shed new fundamental insights to bromate reduction and its implication for transformation of co-existed organic pollutants.