Influence of Media Size and Flow Rate on the Transport of Silver Nanoparticles in Saturated Porous Media PDF Download
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Author: Travis J. Meidinger (MAJ, USAF)
Publisher:
ISBN:
Category :
Languages : en
Pages : 88
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Author: Travis J. Meidinger (MAJ, USAF)
Publisher:
ISBN:
Category :
Languages : en
Pages : 88
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Book Description
Author: Jason R. Flory
Publisher:
ISBN:
Category : Nanoparticles
Languages : en
Pages : 88
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Book Description
Author: Jessica M. Dagher
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 102
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Book Description
With the ubiquitous burst of nanotechnology, silver nanoparticles (AgNPs) have become indispensable in numerous industrial, medicinal, and research applications. Consequently, AgNPs have been alarmingly disposed into subsurface water increasing the risk of human and environmental exposure. While mechanisms of AgNP cytotoxicity have been reported, research studies on AgNP transport in subsurface water are needed, according to U.S. Environmental Protection Agency (EPA). The main goal of this study was to investigate the environmental fate and transport of widely-used Creighton colloidal AgNPs in a laboratory transport system simulating a porous, saturated groundwater aquifer. To achieve this, a large volume of AgNPs was synthesized, characterized using a suite of well-established analytical and microscopy techniques, and manipulated by tangential flow filtration. AgNPs and a conservative tracer, Cl- as a potassium chloride solution, were pulse-injected upward through a one-dimensional laboratory column (5 cm in depth, 2.5 cm diameter) at fixed pH, flow rate, and ionic strength, and pore volume. Breakthrough curves for AgNP transport were constructed using UV-Vis absorption, flame atomic absorption spectroscopy (FAAS) and inductively coupled plasma optical emission spectroscopy (ICP-OES). Smaller AgNPs (1-20 nm in diameter) were found to elute faster than larger AgNPs (1-100 nm in diameter). Flow rate and AgNP size were found to influence the sorption of AgNPs onto the media, as evidenced by the size and shape of the non-equilibrium breakthrough curves. Facilitated transport was attributed to moderate electrostatic repulsions between the negatively charged AgNPs and the polar glass beads. The transport of the AgNPs through the one dimensional laboratory system and the accurate ICP-OES-based quantification of nanosilver concentration in colloidal samples were translated into two novel laboratory experiment modules, which were successfully implemented into the Experimental Nanomaterials and Nanoscience course and the Instrumental Analysis laboratory course at WSU respectively.
Author: Swatantra P. Singh
Publisher: Springer Nature
ISBN: 9811683670
Category : Science
Languages : en
Pages : 623
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Book Description
This book is based on recent trends for the research in emerging environmental contaminants in different compartment of the environment. It provides a recent understanding for the fate, transport, and degradation of emerging contaminants in different environmental sectors, including water, air, and soil. The contents discuss the fate and transport of microplastics, PPCPs, along with the method of detection and degradation. It includes removal of variety of pollutants including microplastics, pharmaceuticals, and personal care products from the water using adsorption technique, electrooxidation, membrane technology and other advance oxidation methods. This volume will be of great value to those in academia and industry involved in environmental science and engineering research.
Author: Manish Kumar
Publisher: Elsevier
ISBN: 0323960014
Category : Science
Languages : en
Pages : 462
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Book Description
Emerging Aquatic Contaminants: One Health Framework for Risk Assessment and Remediation in the Post COVID-19 Anthropocene highlights various sources and pathways of emerging contamination, including their distribution, occurrence, and fate in the aquatic environment. The book provides detailed insight into emerging contaminants' mass flow and behavior in various spheres of the subsurface environment. Possible treatment strategies, including bioremediation and natural attenuation, are discussed. Ecotoxicity, relative environmental risk, human health risk, and current policies, guidelines, and regulations on emerging contaminants are analyzed. This book serves as a pillar for future studies, with the aim of bio-physical remediation and natural attenuation of biotic and abiotic pollution. - Includes real-world applications and case studies to show how these practices can be adopted - Presents global coverage, with a diverse list of contributors, all of whom are experts in the field - Uses illustrative diagrams to provide a clear and foundational understating of the topics
Author: Yorck Felix Adrian
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Amro El Badawy
Publisher:
ISBN:
Category :
Languages : en
Pages : 223
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Book Description
Silver nanoparticles (AgNPs) have received an increased attention in the past decade. This is a result of their unique size-dependent physical and chemical properties and their broad-spectrum toxicity to organisms. The AgNPs have been incorporated in a range of consumer products and have various medical, scientific and industrial applications. Because the hypothesized mechanisms that govern the fate, transport and toxicity of bulk materials may not directly apply to materials at the nanoscale, there are great concerns in the regulatory and research communities about potential environmental impacts associated with the release of AgNPs into the environment. Therefore, the current study aimed at conducting fundamental research to characterize the surface charging and aggregation properties of coated and uncoated AgNPs under various environmental conditions, examine their aggregation kinetics, investigate their mobility in reactive and nor-reactive porous media and assess their toxicity to organisms. The selected AgNPs represent the various surface charging scenarios and the common stabilization mechanisms. The AgNPs were, 1) electrostatically stabilized (uncoated H2-AgNPs, Citrate-AgNPs and NaBH4-AgNPs), 2) sterically stabilized (Polyvinylpyrrolidone coated (PVP-AgNPs)) and 3) electrosterically stabilized (branched polyethyleneimine coated (BPEI-AgNPs)). The type of capping agent and environmental conditions (pH, ionic strength and background electrolytes) had a great impact on the surface charge and aggregation potential of AgNPs. The electrostatically stabilized AgNPs aggregated at high ionic strength, acidic pH conditions and in the presence of divalent cations regardless of the pH. The ionic strength, pH and electrolyte valence had no impact on the surface charge and aggregation of the sterically stabilized AgNPs. This was not the case for the electrosterically stabilized AgNPs which exhibited major changes in surface charge and particle size as a result of the variation in solution chemistry. The examination of the electrolyte-induced aggregation kinetics of the selected AgNPs showed that the aggregation behavior of the electrostatically stabilized AgNPs was in agreement with the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (the AgNPs exhibited both reaction-limited and diffusion-limited regimes) and deviated from the DLVO theory in the case of the sterically and electrosterically stabilized AgNPs. The mobility of the selected AgNPs in quartz sand (QS), ferrihdrite coated sand (FcS) and kaolin coated sand (KcS) media was investigated. The impact of natural organic matter (NOM) on the mobility of the selected AgNPs was also examined. The electrostatically stabilized AgNPs were readily mobile in QS but significantly retained in FcS and KcS with more deposition achieved in the KcS media. The sterically stabilized AgNPs followed the same deposition order as the electrostatically stabilized AgNPs while the electrosterically stabilized BPEI-AgNPs was readily mobile regardless of the porous media investigated. Physicochemical interactions were the dominant filtration mechanism in the majority of the investigated cases but straining played the major role in the deposition of the electrostatically stabilized AgNPs in the KcS medium. The presence of humic acid enhanced the mobility of all investigated AgNPs regardless of the stabilization mechanism or soil reactivity. Finally, rapid screening toxicity tests showed that, under aerobic conditions, the AgNPs exhibited surface charge-dependent toxicity on bacillus species.
Author: Tiantian Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 622
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Book Description
The unique properties of engineered nanoparticles have many potential applications in oil reservoirs, e.g., as emulsion stabilizers for enhanced oil recovery, or as nano-sensors for reservoir characterization. Long-distance propagation (>100 m) is a prerequisite for many of these applications. With diameters between 10 to 100 nanometers, nanoparticles can easily pass through typical pore throats in reservoirs, but physicochemical interaction between nanoparticles and pore walls may still lead to significant retention. A model that accounts for the key mechanisms of nanoparticle transport and retention is essential for design purposes. In this dissertation, interactions are analyzed between nanoparticles and solid surface for their effects on nanoparticle deposition during transport with single-phase flow. The analysis suggests that the DLVO theory cannot explain the low retention concentration of nanoparticles during transport in saturated porous media. Moreover, the hydrodynamic forces are not strong enough for nanoparticle removal from rough surface. Based on different filtration mechanisms, various continuum transport models are formulated and used to simulate our nanoparticle transport experiments through water-saturated sandpacks and consolidated cores. Every model is tested on an extensive set of experimental data collected by Yu (2012) and Murphy (2012). The data enable a rigorous validation of a model. For a set of experiments injecting the same kind of nanoparticle, the deposition rate coefficients in the model are obtained by history matching of one effluent concentration history. With simple assumptions, the same coefficients are used by the model to predict the effluent histories of other experiments when experimental conditions are varied. Compared to experimental results, colloid filtration model fails to predict normalized effluent concentrations that approach unity, and the kinetic Langmuir model is inconsistent with non-zero nanoparticle retention after postflush. The two-step model, two-rate model and two-site model all have both reversible and irreversible adsorptions and can generate effluent histories similar to experimental data. However, the two-step model built based on interaction energy curve fails to fit the experimental effluent histories with delay in the leading edge but no delay in the trailing edge. The two-rate model with constant retardation factor shows a big failure in capturing the dependence of nanoparticle breakthrough delay on flow velocity and injection concentration. With independent reversible and irreversible adsorption sites the two-site model has capability to capture most features of nanoparticle transport in water-saturated porous media. For a given kind of nanoparticles, it can fit one experimental effluent history and predict others successfully with varied experimental conditions. Some deviations exist between model prediction and experimental data with pump stop and very low injection concentration (0.1 wt%). More detailed analysis of nanoparticle adsorption capacity in water-saturated sandpacks reveals that the measured irreversible adsorption capacity is always less than 35% of monolayer packing density. Generally, its value increases with higher injection concentration and lower flow velocities. Reinjection experiments suggest that the irreversible adsorption capacity has fixed value with constant injection rate and dispersion concentration, but it becomes larger if reinjection occurs with larger concentration or smaller flow rate.
Author: Wan Lutfi bin Wan Johari Wan Johari
Publisher:
ISBN:
Category :
Languages : en
Pages : 250
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Book Description
Author:
Publisher: Elsevier
ISBN: 0080994156
Category : Technology & Engineering
Languages : en
Pages : 240
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Book Description
Nanomaterials in the Environment covers all aspects of manufactured nanomaterials and their impact and behavior in the environment. Starting with a general overview of the field, emphasizing key points and background, the book then covers crucial specific areas, including nanomaterial transformations in the environment due to dissolution, aggregation, and other processes, and the modeling of environmental exposure and fate. A chapter on formation of the “eco-corona investigates the state of the art with specific reference to the protein corona literature in human health. Finally, there are chapters on mechanisms of biouptake and toxicity. The fast-moving nature of the field and the quality of the submissions make this book essential reading for all those working in this area. It is suitable for researchers from Masters-level upwards, and for regulators and industry. The book can also be used as a high-level teaching aid. Edited and written by leaders in this area Environmental behavior and effects are discussed in depth Useful for specialists and generalists at all levels of experience
