Degradation and mechanism of PAHs by Fe-based activated persulfate: Effect of temperature and noble metal

Ye Wang; Huifang Tian; Congcong Zhang; Jingyu Xu; Xingshuang Liu; Fujun Ma; Xinqing Wei; Yifei Sun

doi:10.1016/j.scitotenv.2024.172768

Degradation and mechanism of PAHs by Fe-based activated persulfate: Effect of temperature and noble metal

Sci Total Environ. 2024 Jun 25:931:172768. doi: 10.1016/j.scitotenv.2024.172768. Epub 2024 Apr 25.

Authors

Ye Wang¹, Huifang Tian¹, Congcong Zhang¹, Jingyu Xu¹, Xingshuang Liu², Fujun Ma³, Xinqing Wei⁴, Yifei Sun⁵

Affiliations

¹ School of Energy and Power Engineering, Beihang University, Beijing 100191, China.
² College of Environment and Ecology, Hainan University, Haikou 570228, China.
³ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
⁴ Tianjin JC Environmental Services, Tianjin 300202, China.
⁵ School of Energy and Power Engineering, Beihang University, Beijing 100191, China; Research Center for Advanced Energy and Carbon Neutrality, Beihang University, Beijing 100191, China; College of Environment and Ecology, Hainan University, Haikou 570228, China. Electronic address: sunif@buaa.edu.cn.

PMID: 38670359
DOI: 10.1016/j.scitotenv.2024.172768

Abstract

The accumulation of contaminants like PAHs in soil due to industrialization, urbanization, and intensified agriculture poses environmental challenges, owing to their persistence, hydrophobic nature, and toxicity. Thus, the degradation of PAHs has attracted worldwide attention in soil remediation. This study explored the effect of noble metal and temperature on the degradation of various polycyclic aromatic hydrocarbons (PAHs) in soil, as well as the types of reactive radicals generated and mechanism. The Fe-Pd/AC and Fe-Pt/AC activated persulfate exhibited high removal efficiency of 19 kinds of PAHs, about 79.95 % and 83.36 %, respectively. Fe-Pt/AC-activated persulfate exhibits superior degradation efficiency than that on Fe-Pd/AC-activated persulfate, due to the higher specific surface area and dispersity of Pt particles, thereby resulting in increased reactive radicals (·OH, SO₄^-· and ·OOH). Additionally, thermal activation enhances the degradation of PAHs, with initial efficiencies of 64.20 % and 55.49 % on Fe-Pd/AC- and Fe-Pt/AC-activated persulfate systems respectively, increasing to 76.05 % and 73.14 % with elevated temperatures from 21.5 to 50 °C. Metal and thermal activation facilitate S₂O₈^2- activation, generating reactive radicals, crucial for the degradation of PAHs via ring opening and oxygen hydrogenation reactions, yielding low-ring oxygen-containing derivatives such as organic acids, keto compounds, ethers, and esters. Furthermore, understanding the impact of parameters such as activation temperature and the types of noble metals on the degradation of PAHs within the activated persulfate system provides a theoretical foundation for the remediation of PAH-contaminated soil.

Keywords: Degradation mechanism; Iron-based bimetallic activator; PAHs; Thermal activation.