title: Visible light photodegradation of phenanthrene catalyzed by Fe(III)-smectite: role of soil organic matter.
abstract: In the present study, phenanthrene is employed as a model to explore the roles played by three soil organic matter (SOM) fractions, i.e., dissolved organic matter (DOM), humic acid (HA), and fulvic acid (FA), in its photodegradation with assistance of Fe(III)-smectite under visible-light. Slight decrease in phenanthrene photodegradation rate was observed in the presence of DOM, which is explained in terms of oxidative-radical competition between DOM and target phenanthrene molecules due to the high electron-donor capacity of phenolic moieties in DOM. On the other hand, a critic content is observed with FA (0.70mg/g) and HA (0.65mg/g). Before reaching the critic content, the removal of phenanthrene is accelerated; while after that, the photodegradation rate is suppressed. The acceleration of phenanthrene degradation can be attributed to the photosensitization of FA and HA. Due to the strong interaction between phenanthrene and the phenyl rings, however, the retention of phenanthrene on SOM-Fe(III)-smectite in the presence of high content of HA or FA is enhanced, thus slowing down its photodegradation. Those observations provide valuable insights into the transformation and fate of PAHs in the natural soil environment and open a window for using clay-humic substances complexes for remediation of contaminated soil.
authors.affiliation: Laboratory of Eco-Materials and Sustainable Technology LEMST, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China. jiahz0143@yahoo.com.cn
authors.forename: Hanzhong
authors.initials: H
authors.lastname: Jia
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Fan
authors.forename: Mingdeng
authors.initials: M
authors.lastname: Liu
authors.forename: Wenye
authors.initials: W
authors.lastname: Deng
authors.forename: Chuanyi
authors.initials: C
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D001578:Benzopyrans / Q000737:chemistry* / Q000528:radiation effects; D002384:Catalysis; D052918:Environmental Restoration and Remediation / Q000379:methods; D005290:Ferric Compounds / Q000737:chemistry* / Q000528:radiation effects; D006812:Humic Substances; D008027:Light; D010616:Phenanthrenes / Q000737:chemistry* / Q000528:radiation effects; D010782:Photolysis; D017640:Silicates / Q000737:chemistry* / Q000528:radiation effects; D012989:Soil Pollutants / Q000737:chemistry* / Q000528:radiation effects; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D001578:Benzopyrans; D005290:Ferric Compounds; D006812:Humic Substances; D010616:Phenanthrenes; D017640:Silicates; D012989:Soil Pollutants; C031181:phenanthrene; C033214:Smectite; C005023:fulvic acid