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Removal of Stabilized Silver Nanoparticles from Ohio River Water by Potable Water Treatment Processes
Citation:
Patterson, C., H. Salih, A. El-Badawy, C. Impellitteri, AND T. Tolaymat. Removal of Stabilized Silver Nanoparticles from Ohio River Water by Potable Water Treatment Processes. In Proceedings, AWWA Water Quality Technology Conference (CD ROM), Toronto, ON, CANADA, November 04 - 08, 2012. AWWA Research Foundation, Denver, CO, 1-100, (2012).
Impact/Purpose:
Silver nanoparticles (AgNPs) may be released into the environment in the stages of manufacture, refinement, application, and disposal. NPs are emerging as a new type of contaminant in water and wastewater. The purpose of this research is to investigate the removal of different types of stabilized Ag NPs by potable water treatment processes and to assess the impact of stabilization mechanisms on the mobility of AgNPs in natural water.
Description:
Due to their extensive use, silver nanoparticles (Ag NPs) are likely to occur in drinking water sources. Once released into the environment they are considered an emerging contaminant in water and wastewater. The main objective of this research is to investigate the removal of different types of stabilized Ag NPs by potable water treatment processes. This was achieved by 1) Synthesizing different types of stable Ag NPs using various techniques to obtain Ag NPs in different shapes, sizes and surface properties. Different stabilizing agents were prepared in order to prevent their aggregation including hydrogen reduced, citrate reduced, borohydride reduced and Polyvinylpyrrolidone (PVP) stabilized Ag NPs, 2) Characterizing all Ag NPs under investigation to determine their aggregation potential by obtaining their particle size distribution with time, Zeta potential profiles, XPS (in natural water), TEM images, XRD and FTIR analysis, and 3) Investigating the efficacy of conventional water treatment processes (i.e. coagulation, flocculation, sedimentation and sand filtration in removing these stabilized Ag NPs from natural water). The synthesized Ag NPs are very stable in water due to steric and/or electrostatic stabilization mechanisms. Unlike citrate Ag NPs, the PVP and the BPEI Ag NPs are not affected by the presence of alum at any dose. Ag NPs interact with natural water colloids and get removed by attaching to the settling colloids. Aggregated Ag NPs are released back to water in their original nano-size when these aggregates are mechanically disturbed.
