title: Photoreduction and stabilization capability of molecular weight fractionated natural organic matter in transformation of silver ion to metallic nanoparticle.
abstract: Photoinduced reduction of silver ion (Ag(+)) to silver nanoparticles (AgNPs) by dissolved organic matter (DOM) plays a crucial role in the transformation and transport of engineered AgNPs and Ag(+) in aquatic environments. DOM is a mixture of natural polymers with wide molecular weight (MW) distribution, and the roles of specific components of DOM in the photoreduction of Ag(+) to AgNPs are still not understood. In this study, MW fractionated natural organic matter (Mf-NOM) were investigated for their roles on the photoreduction process and stabilization of the formed AgNPs. This photoinduced reduction process depends highly on pH, concentration of Ag(+) and NOM, light quality, and the MW of Mf-NOM. Monochromatic radiation and light attenuation correction suggested that the difference of Mf-NOM on reduction was mainly ascribed to the differential light attenuation of Mf-NOM rather than the "real" reductive ability. More importantly, compared with low MW fractions, the high MW Mf-NOMs exhibit drastically higher capability in stabilizing the photosynthesized AgNPs against Ca(2+)-induced aggregation. This finding is important for a better understanding of the differential roles of Mf-NOM in the transformation and transport of Ag(+) and engineered AgNPs in DOM-rich surface water.
authors: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors: Yongguang
authors: Y
authors: Yin
authors: Mohai
authors: M
authors: Shen
authors: Xiaoxia
authors: X
authors: Zhou
authors: Sujuan
authors: S
authors: Yu
authors: Jingbo
authors: J
authors: Chao
authors: Jingfu
authors: J
authors: Liu
authors: Guibin
authors: G
authors: Jiang
mesh_terms: D006812:Humic Substances / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010316:Particle Size; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects; D013472:Sunlight; D013499:Surface Properties; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D006812:Humic Substances; D014874:Water Pollutants, Chemical; D012834:Silver