title: 2-Nitrophenol reduction promoted by S. putrefaciens 200 and biogenic ferrous iron: the role of different size-fractions of dissolved organic matter.
abstract: The reduction of nitroaromatic compounds (listed as a priority pollutant) in natural subsurface environments typically coexists with dissimilatory reduction of iron oxides effected by dissolved organic matter (DOM). Investigating the impact of the DOM that influences those reduction processes is crucial for understanding and predicting the geochemical fate of these environmental species. This study investigated the impact of different molecular weight DOM fractions (DMWDs) on the 2-nitrophenol (2-NP) reduction by S. putrefaciens 200 (SP200) and α-Fe2O3 with lactate (excluding electron donor interference). Kinetic measurements demonstrated that 2-NP reduction rates were affected by the redox reactivity of active species under DMWDs (denoted as L-DOM, M-DOM, and H-DOM). The enhanced reduction rates are consistent with the negative shifts in peak oxidation potential values, the increases in HA-like/FA-like values, aromaticity index values and electron transfer capacity values. L-DOM acted mainly as ligands to complex Fe(II), whereas the significant role of H-DOM in reductive reactions should be acting as an electron shuttle, transferring electrons from SP200 to Fe(III) and 2-NP and from biogenic Fe(II) to 2-NP, further accelerating the 2-NP reductions. Those observations provide valuable insights into the role of DOM in the biogeochemical redox processes and the remediation of contaminated soil in a natural environment.
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, PR China; Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China; Graduate University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Zhenke
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, PR China. Electronic address: taoliang@soil.gd.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Tao
authors.affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, PR China. Electronic address: cefbli@soil.gd.cn.
authors.forename: Fangbai
authors.initials: F
authors.lastname: Li
mesh_terms: D004563:Electrochemistry; D004583:Electrons; D005290:Ferric Compounds; D005296:Ferrous Compounds / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry*; D010084:Oxidation-Reduction; D020614:Shewanella putrefaciens / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D009596:Nitrophenols; C000499:ferric oxide; C045573:2-nitrophenol; C034236:ferrous oxide
keywords: 2-nitrophenol; Dissimilatory reduction of iron oxides; Dissolved organic matter; Electron transfer capacities; Interfacial reaction