Enhanced catalytic oxidation of 2,4-dichlorophenol via singlet oxygen dominated peroxymonosulfate activation on CoOOH@Bi
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RESEARCH ARTICLE
Enhanced catalytic oxidation of 2,4-dichlorophenol via singlet oxygen dominated peroxymonosulfate activation on CoOOH@Bi2O3 composite Tianhao Xi1,2, Xiaodan Li3, Qihui Zhang1,2, Ning Liu3, Shu Niu1,2, Zhaojun Dong1,2, Cong Lyu (✉)1,2 1 Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130026, China 2 Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130026, China 3 China Northeast Municipal Engineering Design and Research Institute Co. Ltd., Changchun 130021, China
HIGHLIGHTS
GRAPHIC ABSTRACT
• Bi2O3 cannot directly activate PMS. • Bi2O3 loading increased the specific surface area and conductivity of CoOOH. • Larger specific surface area provided more active sites for PMS activation. • Faster electron transfer rate promoted the generation of reactive oxygen species. • 1O2 was identified as dominant ROS in the CoOOH@Bi2O3/PMS system.
ARTICLE INFO Article history:
Received 16 May 2020 Revised 12 July 2020 Accepted 19 July 2020 Available online 9 October 2020 Keywords: Cobalt oxyhydroxide Bismuth oxide Peroxymonosulfate 2, 4-dichlorophenol Singlet oxygen Electron transfer
ABSTRACT Cobalt oxyhydroxide (CoOOH) has been turned out to be a high-efficiency catalyst for peroxymonosulfate (PMS) activation. In this study, CoOOH was loaded on bismuth oxide (Bi2O3) using a facile chemical precipitation process to improve its catalytic activity and stability. The result showed that the catalytic performance on the 2,4-dichlorophenol (2,4-DCP) degradation was significantly enhanced with only 11 wt% Bi2O3 loading. The degradation rate in the CoOOH@Bi2O3/ PMS system (0.2011 min–1) was nearly 6.0 times higher than that in the CoOOH/PMS system (0.0337 –1 min ). Furthermore, CoOOH@Bi2O3 displayed better stability with less Co ions leaching (16.4% lower than CoOOH) in the PMS system. These phenomena were attributed to the Bi2O3 loading which significantly increased the conductivity and specific surface area of the CoOOH@Bi2O3 composite. Faster electron transfer facilitated the redox reaction of Co (III) / Co (II) and thus was more favorable for reactive oxygen species (ROS) generation. Meanwhile, larger specific surface area furnished more active sites for PMS activation. More importantly, there were both non-radical (1O2) and radicals (SO4–•, O2–•, and OH•) in the CoOOH@Bi2O3/PMS system and 1O2 was the dominant one. In general, this study provided a simple and practical strategy to enhance the catalytic activity and stability of cobalt oxyhydroxide in the PMS system. © Higher Education Press 2020
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Introduction
2,4-Dichlorophenol is a type of chlorophenols that is used in the preparation of preservatives, dyes, insecticides, and fungicides (Meharg et al., 2000). In the application and processing of these substances, 2,4-DCP will enter the
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environment and pose a huge threat to human health. Many biological and physical methods have been developed for the removal of
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