title: Removal of silver nanoparticles by coagulation processes.
abstract: Commercial use of silver nanoparticles (AgNPs) will lead to a potential route for human exposure via potable water. Coagulation followed by sedimentation, as a conventional technique in the drinking water treatment facilities, may become an important barrier to prevent human from AgNP exposures. This study investigated the removal of AgNP suspensions by four regular coagulants. In the aluminum sulfate and ferric chloride coagulation systems, the water parameters slightly affected the AgNP removal. However, in the poly aluminum chloride and polyferric sulfate coagulation systems, the optimal removal efficiencies were achieved at pH 7.5, while higher or lower of pH could reduce the AgNP removal. Besides, the increasing natural organic matter (NOM) would reduce the AgNP removal, while Ca(2+) and suspended solids concentrations would also affect the AgNP removal. In addition, results from the transmission electron microscopy and X-ray diffraction showed AgNPs or silver-containing nanoparticles were adsorbed onto the flocs. Finally, natural water samples were used to validate AgNP removal by coagulation. This study suggests that in the case of release of AgNPs into the source water, the traditional water treatment process, coagulation/sedimentation, can remove AgNPs and minimize the silver ion concentration under the well-optimized conditions.
authors: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors: Qian
authors: Q
authors: Sun
authors: Yan
authors: Y
authors: Li
authors: Ting
authors: T
authors: Tang
authors: Zhihua
authors: Z
authors: Yuan
authors: Chang-Ping
authors: CP
authors: Yu
mesh_terms: D000327:Adsorption; D000534:Alum Compounds / Q000737:chemistry; D000536:Aluminum Hydroxide / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000534:Alum Compounds; D002712:Chlorides; D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; C016213:aluminum oxychloride; C041524:aluminum sulfate; C024823:ferric sulfate; D012834:Silver; D000536:Aluminum Hydroxide; C024555:ferric chloride
keywords: Coagulation; Flocs; Removal efficiency; Silver ion release; Silver nanoparticles