页岩气返排废水中有机物去除的分子比较：臭氧与芬顿法

这些结果揭示了SGFW处理过程中臭氧的选择性氧化和•OH的非选择性氧化，为SGFW处理方法的选择提供了理论支持。

1. 文章信息

标题：Molecular comparison of organic matter removal from shale gas flowback wastewater: Ozonation versus Fenton process

中文标题：页岩气返排废水中有机物去除的分子比较：臭氧与芬顿法

2. 文章链接

https://doi.org/10.1016/j.scitotenv.2023.167147

3. 期刊信息

期刊名：Science of The Total Environment Volume 905, 20 December 2023, 167147

4. 作者信息：Xinglong Chen, Guonan Zhao, Zhuowen Yang, Qibin Li

Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, 611756, China

5.文中所用产品型号：3S-J5000

重点

•研究了臭氧氧化和芬顿法处理SGFW的DOM组成。

•臭氧氧化和芬顿工艺对SGFW DOM的影响存在显著差异。

•比较了臭氧氧化和芬顿法的降解机理。

摘要

页岩气开采过程中会产生大量含有难降解有机物的页岩气返排废水，如果处理不当，会对环境造成严重威胁。然而，SGFW中极其复杂的有机物组成尚不清楚，它们在O3-和•oh主导体系中的转化途径也不清楚，这制约了处理工艺的选择和操作参数的优化。采用电喷雾电离傅立叶变换离子回旋共振质谱法比较研究了臭氧法和Fenton法处理SGFW中溶解性有机物（DOM）的去除特性和反应机理。结果表明，两种工艺均能降解低氧高不饱和酚类有机物、多酚类化合物和多环芳烃，并将其转化为脂肪类有机物和高氧高不饱和酚类有机物。随着活性氧（臭氧氧化作用为O3， Fenton氧化作用为•OH）作用的增加，臭氧氧化过程中降解产物（主要是脂肪族有机物）增加。而在Fenton工艺中，更大范围的DOM被去除，没有脂肪族有机物的积累。臭氧化和Fenton法降解DOM的主要途径是氧加成反应（+ 30、+H2O2和+2O）。臭氧化反应表现为更剧烈的氧合、羟化和羧化反应，Fenton法表现为更剧烈的断链反应。这些结果揭示了SGFW处理过程中臭氧的选择性氧化和•OH的非选择性氧化，为SGFW处理方法的选择提供了理论支持。

Shale gas extraction process generates a large amount of shale gas flowback wastewater (SGFW) containing refractory organic compounds, which can pose serious environmental threats if not properly treated. However, the extremely complex compositions of organics in SGFW are still unknown and their transformation pathways in O3- and •OH-dominated systems are not well recognized, which restrain the selection of treatment technology and optimization of operational parameters. The removal characteristics and reaction mechanism of dissolved organic matter (DOM) in SGFW treated by ozonation and Fenton processes were comparatively investigated using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The results showed that both processes could degrade low-oxygen highly unsaturated and phenolic organics, polyphenolics and polycyclic aromatics, and transform them into aliphatic organics and high-oxygen highly unsaturated and phenolic organics. With increasing action of reactive oxygen species (O3 for ozonation and •OH for Fenton process), the degradation products (mainly aliphatic organics) increased during ozonation. However, in Fenton process, a wider range of DOM was removed without aliphatic organics accumulation. The degradation mechanisms of DOM during ozonation and Fenton processes included oxygen addition reactions (+3O, +H2O2, and +2O) as dominant pathways. However, ozonation showed more violent oxygenation, hydroxylation, and carboxylation, while Fenton process presented more violent chain-breaking reactions. These results revealed the selective oxidation of ozone and nonselective oxidation of •OH during SGFW treatment, and provided theoretical support for selecting SGFW treatment approaches.