Li Yibing, Zhang Lixun, Wang Jing, Xu Shan, Zhang Zhengfang, Guan Yuntao
Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Guangdong Provincial Engineering Technology Research Center for Urban Water Cycle and Water Environment Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration, Guangdong Provincial Engineering Technology Research Center for Urban Water Cycle and Water Environment Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China; State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
Environ Int. 2024 Dec;194:109098. doi: 10.1016/j.envint.2024.109098. Epub 2024 Oct 28.
The nano zero-valent iron (nZVI) activated persulfate (PS) is recognized as a promising approach to degrade 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), which is ubiquitous in the soil at electronic waste sites. However, all the reported studies were performed in liquids, gaps in the real behaviour and microbial contribution to the degradation of BDE-47 in soil media need to be urgently filled. The removal efficiency of BDE-47 is low using traditional nZVI as activator because of its aggregation and corrosion. Herein, we designed a novel layered double oxide supported sulfidated nano zero-valent iron (S-nZVI@LDO) composite and explored the performance of S-nZVI@LDO/PS to remediate BDE-47 contaminated soil. The results showed that S-nZVI@LDO has excellent stability and superior reduction capability. It could couple PS to achieve a rapid and efficient degradation of BDE-47, and the removal efficiency reached 92.31 % (5 mg/kg) within 6 h, which was much higher than that of n-ZVI/PS (53.38 %) or S-nZVI/PS (75.69 %). The kinetic constant of BDE-47 degradation by S-nZVI@LDO/PS was 23.6 and 3.7 times higher than that by single S-nZVI@LDO and nZVI/PS, respectively. It is attributable to the efficient production of SO, •OH, O, and O in the system, in which SO and •OH dominated. The bioinformatic analysis demonstrate that soil remediation by S-nZVI@LDO/PS significantly enriched aromatic compounds-degrading bacteria and increased the abundance of hydrocarbon degradation functions. Microbial degradation may play important roles in the BDE-47 degradation and soil quality recovery. The identification of degradation pathways suggests that BDE-47 was degraded to very low-toxic products based on GHS toxicity prediction through a series process of debromination, hydroxylation, cleavage central oxygen, and ring opening, or even completely mineralized. The findings may provide significant implications for the in-situ clean-up of brominated flame retardants in contaminated soil using S-nZVI@LDO/PS Fenton-like system.
纳米零价铁（nZVI）活化过硫酸盐（PS）被认为是降解2,2',4,4'-四溴二苯醚（BDE-47）的一种很有前景的方法，BDE-47在电子垃圾场的土壤中普遍存在。然而，所有已报道的研究都是在液体中进行的，BDE-47在土壤介质中的实际降解行为和微生物贡献方面的空白急需填补。使用传统的nZVI作为活化剂时，BDE-47的去除效率较低，因为其会发生团聚和腐蚀。在此，我们设计了一种新型的层状双氧化物负载硫化纳米零价铁（S-nZVI@LDO）复合材料，并探究了S-nZVI@LDO/PS修复BDE-47污染土壤的性能。结果表明，S-nZVI@LDO具有优异的稳定性和卓越的还原能力。它可以与PS耦合，实现对BDE-47的快速高效降解，在6小时内去除效率达到92.31%（5毫克/千克），远高于n-ZVI/PS（53.38%）或S-nZVI/PS（75.69%）。S-nZVI@LDO/PS降解BDE-47的动力学常数分别比单一的S-nZVI@LDO和nZVI/PS高23.6倍和3.7倍。这归因于体系中高效产生的SO、•OH、O和O，其中SO和•OH起主导作用。生物信息学分析表明，S-nZVI@LDO/PS进行土壤修复可显著富集芳香化合物降解菌，并增加烃类降解功能的丰度。微生物降解可能在BDE-47降解和土壤质量恢复中发挥重要作用。降解途径的鉴定表明，基于GHS毒性预测，BDE-47通过一系列脱溴、羟基化、裂解中心氧和开环过程降解为低毒产物，甚至完全矿化。这些发现可能为使用S-nZVI@LDO/PS类芬顿体系原位清理污染土壤中的溴化阻燃剂提供重要启示。
