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Environmental Behavior of Silver Nanoparticles: Emissions from Consumer Products and Toxicty in Waste Treatment

Gitipour, Alireza
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470043053

Abstract Details

2016, PhD, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
Nanotechnology has undergone a dramatic increase in popularity in the last decade due to the unique physicochemical characteristics of engineered nanomaterials (ENMs). Currently, approximately a quarter of all nano-enabled consumer products contain silver nanoparticles (AgNPs). AgNPs are incorporated into a wide range of consumer products (e. g., textiles, filters, disinfectants, and washing machines) and have a wide range of medical, industrial and scientific applications. The increased application of AgNPs will inevitably lead to their release into environmental systems. Since the presumed mechanisms governing the fate, transport and toxicity of matter at the bulk scale may not directly apply to nanomaterials, the potential environmental impacts associated with the release of AgNPs must be evaluated. Furthermore, AgNPs are manufactured with a wide range of physicochemical properties that impact their fate, transport and toxicity in the environment. To this end, the impact of silver nanoparticles on the composting of municipal solid waste was evaluated. Neither the presence of AgNPs nor the presence of Ag+ had a statistically significant influence on leachate, gas and solid quality parameters, and therefore, on overall composting performance. However, AgNPs and Ag+ both changed the overall structure of the bacterial communities within the compost. Nevertheless, the functional performance of the composting process was not significantly affected due to the abundance and functional redundancy of the bacterial communities within the compost samples. While surface transformations of AgNPs to AgCl and Ag2S reduce toxicity, complexation with organic matter may also play a role. The results of this study further suggest that at relatively low concentrations of AgNPs, these organically rich waste management systems can withstand the presence of AgNPs. The microbial toxicity of silver nanoparticles stabilized with different capping agents were evaluated under anaerobic conditions. The AgNPs investigated were similar in size and shape but varied in surface charge. At lower AgNPs concentrations, the anaerobic decomposition process was not affected although the diversity of the microbial community was impacted. Interestingly, at higher concentrations only the cationic AgNPs demonstrated toxicity, while, the neutral and negatively charged AgNPs did not exhibit toxicity. These findings indicate that there are multiple mechanisms for nanoparticles toxicity. In addition to the disposal studies, a study of a commonly-utilized nanosilver solution using a simulated dental unit water delivery system assessed the fate, mode of interaction and physicochemical transformations of AgNPs under a realistic usage scenario. The disinfection process led to the disappearance of the capping agents and consequently transformations of AgNPs. In addition to further understanding the transformations that occur in the process, adsorption of the AgNPs onto the biofilms surface was demonstrated which may assist in further understanding the toxicity mechanisms of AgNPs to biofilms. Finally, a comprehensive review was conducted to identify the key issues and knowledge gaps concerning the environmental impact of AgNPs in consumer products. This review summarizes the existing data related to characterization techniques, routes of environmental exposure and potential ecological risks of AgNPs and provides potential directions for future research.
Stephen Thiel, Ph.D. (Committee Chair)
Thabet Tolaymat, Ph.D. (Committee Member)
Vadim Guliants, Ph.D. (Committee Member)
Vesselin Shanov, Ph.D. (Committee Member)
George Sorial, Ph.D. (Committee Member)
212 p.
Chemical Engineering
Silver Nanoparticles; Physicochemical Transformations of AgNPs; Impact of Silver Nanomaterials on Waste Treatment; Anaerobic Digestion; Impact of AgNPs on Waste Management Systems; Environmental Behavior of Silver Nanoparticles

Recommended Citations

Citations

  • Gitipour, A. (2016). Environmental Behavior of Silver Nanoparticles: Emissions from Consumer Products and Toxicty in Waste Treatment [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470043053

    APA Style (7th edition)

  • Gitipour, Alireza. Environmental Behavior of Silver Nanoparticles: Emissions from Consumer Products and Toxicty in Waste Treatment. 2016. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470043053.

    MLA Style (8th edition)

  • Gitipour, Alireza. "Environmental Behavior of Silver Nanoparticles: Emissions from Consumer Products and Toxicty in Waste Treatment." Doctoral dissertation, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470043053

    Chicago Manual of Style (17th edition)

ucin1470043053
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© 2016, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.
Release 3.2.12