Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
Environ Sci Technol. 2022 Oct 4;56(19):13996-14007. doi: 10.1021/acs.est.2c03590. Epub 2022 Sep 9.
In this study, a wet scrubber coupled with a persulfate-based advanced oxidation process [carbocatalysts/peroxymonosulfate (PMS)] was demonstrated to efficiently remove gaseous volatile organic compounds (VOCs). The removal efficiency of a representative VOC, styrene, was stable at above 98%, and an average mineralization rate was achieved at 76% during 2 h. The removal efficiency of the carbocatalysts/PMS wet scrubber for styrene was much higher than that of pure water, carbocatalysts/water, or PMS/water systems. Quenching experiments, electron spin resonance spectroscopy, in-situ Raman spectroscopy and density functional theory (DFT) calculations indicated that singlet oxygen (O) and oxidative complexes are the main reactive oxygen species and that both contributed to styrene removal. In particular, carbonyl groups (C═O) in the carbocatalyst were found to be the active sites for activating PMS during styrene oxidation. The role of O was discovered to be benzene ring breaking and a possible non-radical oxidation pathway of styrene was proposed based on time-of-flight mass spectroscopy which was further verified by DFT calculations. In particular, the electron transfer process of multi world carbon nanotubes-PMS* in styrene oxidation was further studied in-depth by experiments and DFT calculations. The unstable vinyl on styrene was simultaneously degraded by the oxidative complexes and O into benzene, and finally oxidized by O into HO and CO. This study provides an effective method for VOC removal and clearly illustrates the complete degradation mechanism of styrene in a nonradical PMS-based process by a wet scrubber.
在这项研究中，湿式洗涤器与过硫酸盐基高级氧化工艺[碳催化剂/过一硫酸盐（PMS）]相结合，被证明可以有效地去除气态挥发性有机化合物（VOC）。在 2 小时内，代表性 VOC（苯乙烯）的去除效率稳定在 98%以上，平均矿化率达到 76%。碳催化剂/PMS 湿式洗涤器对苯乙烯的去除效率远高于纯水、碳催化剂/水或 PMS/水系统。猝灭实验、电子顺磁共振波谱、原位拉曼光谱和密度泛函理论（DFT）计算表明，单线态氧（O）和氧化复合物是主要的活性氧物种，两者都有助于苯乙烯的去除。特别是，碳催化剂中的羰基（C═O）被发现是在苯乙烯氧化过程中激活 PMS 的活性位点。发现 O 的作用是破坏苯环，并根据飞行时间质谱提出了苯乙烯的可能非自由基氧化途径，该途径进一步通过 DFT 计算得到验证。特别是，通过实验和 DFT 计算，进一步深入研究了多世界碳纳米管-PMS*在苯乙烯氧化中的电子转移过程。苯乙烯上不稳定的乙烯基被氧化复合物和 O 同时降解为苯，最后被 O 氧化为 HO 和 CO。本研究为 VOC 去除提供了一种有效方法，并通过湿式洗涤器清楚地说明了非自由基 PMS 工艺中苯乙烯的完全降解机制。
