Hydrogen Peroxide-Assisted Alkaline Defluorination of the Fumigant and Potent Greenhouse Gas, Sulfuryl Fluoride: Hydrogen Peroxide as a Nucleophilic Reagent

IF 10.8 1区 环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL
Zhihao Chen, Chengjin Wang, Shaik Mahamad Allabakshi, Joseph J Pignatello
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引用次数: 0

Abstract

Sulfuryl fluoride (SO2F2, SF) is an effective and increasingly popular fumigant for treating buildings and commodities in international trade but has come under scrutiny as a potent greenhouse gas. Passage of vent gases through an alkaline spray has been proposed for scrubbing SF, but base hydrolysis is insufficiently fast and generates equal yields of fluoride and fluorosulfate, the latter of unknown environmental hazard. We report here that alkaline hydrogen peroxide (H2O2) markedly accelerates SF removal and gives nearly quantitative yield of fluoride, with fluorosulfate produced in less than 3.5% yield. The other major products are sulfate, peroxymonosulfate, and oxygen. The oxidation state of S was unchanged. Hydroxyl and superoxide radical scavengers had no effect on the rate. The reaction proceeds by sequential nucleophilic displacement of fluoride by hydroperoxide ion (HO2) to form a transient diperoxysulfate species that rapidly undergoes intramolecular redox rearrangement to give sulfate and singlet oxygen. Peroxymonosulfate, produced through side reactions, can fully defluorinate SF as well, although more slowly. Two new peaks were detected in the 19F-NMR spectrum corresponding to intermediates. Fluoride can be removed conventionally, and the other products are innocuous or short-lived. Thus, H2O2-assisted alkaline defluorination promises to be an effective method for scrubbing spent SF fumes and preventing SF from reaching the atmosphere. This study highlights the benefits of H2O2 and peroxymonosulfate as nucleophiles in remediation chemistry.

Abstract Image

过氧化氢辅助熏蒸剂和强效温室气体氟化硫的碱性脱氟:过氧化氢作为亲核试剂
硫酰氟(SO2F2,SF)是一种有效且日益流行的熏蒸剂,用于处理建筑物和国际贸易中的商品,但作为一种强烈的温室气体,它受到了严格的审查。有人建议将排放气体通过碱性喷雾来洗涤 SF,但碱性水解速度不够快,而且产生的氟化物和氟硫酸盐的产量相同,后者对环境的危害未知。我们在此报告的是,碱性过氧化氢(H2O2)明显加快了 SF 的去除速度,氟化物的产量几乎达到定量,而氟硫酸盐的产量不到 3.5%。其他主要产物是硫酸盐、过硫酸盐和氧。S 的氧化态保持不变。羟基和超氧自由基清除剂对速率没有影响。反应通过过氧化氢离子(HO2-)对氟化物的顺序亲核置换作用进行,形成瞬时二过氧硫酸盐物种,该物种迅速发生分子内氧化还原重排,生成硫酸盐和单线态氧。通过副反应产生的过氧单硫酸盐也能使 SF 完全脱氟,但速度较慢。在 19F-NMR 光谱中检测到两个与中间产物相对应的新峰值。氟化物可以通过传统方法去除,而其他产物则是无害的或短暂的。因此,H2O2 辅助碱性脱氟有望成为洗涤废旧 SF 烟气和防止 SF 进入大气的有效方法。本研究强调了 H2O2 和过一硫酸盐作为亲核物在修复化学中的优势。
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来源期刊
环境科学与技术
环境科学与技术 环境科学-工程:环境
CiteScore
17.50
自引率
9.60%
发文量
12359
审稿时长
2.8 months
期刊介绍: Environmental Science & Technology (ES&T) is a co-sponsored academic and technical magazine by the Hubei Provincial Environmental Protection Bureau and the Hubei Provincial Academy of Environmental Sciences. Environmental Science & Technology (ES&T) holds the status of Chinese core journals, scientific papers source journals of China, Chinese Science Citation Database source journals, and Chinese Academic Journal Comprehensive Evaluation Database source journals. This publication focuses on the academic field of environmental protection, featuring articles related to environmental protection and technical advancements.
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