Comparison of enhanced microsphere transport in an iron-oxide-coated porous medium by pre-adsorbed and co-depositing organic matter

Yang, Xiaojian; Deng, Shihuai; Wiesner, Mark R.

doi:10.1016/j.cej.2013.06.122

Cited by 11 publications

(6 citation statements)

References 43 publications

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“…A 0.5 PV pulse of SRHA at 5 mg/L through the column matrix. This produced a monolayer of randomly distributed OM compounds on the sand granular surface, as confirmed in our previous studies. ,, …”

Section: Methodssupporting

confidence: 87%

“…Following that, TPEs were conducted to quantify the impact of SRHA on particle deposition, which consisted of the following: A prolonged pulse of 6 PVs of particle dispersion at 10.4 ppm to allow a sustained increase in concentrations in the column effluent to be generated as breakthrough proceeds. A 0.5 PV pulse of SRHA at 5 mg/L through the column matrix. This produced a monolayer of randomly distributed OM compounds on the sand granular surface, as confirmed in our previous studies. ,, A second 6 PV particle pulse at 10.4 ppm again to display the effect of the adsorbed OM on particle transport. …”

Section: Methodssupporting

confidence: 84%

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Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling

Yang

Zhang

Chen

et al. 2015

Environ. Sci. Technol.

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The investigation on factors that affect the impact of natural organic matter (NOM) on colloid transport in complex hydraulic flow systems remains incomplete. Using our previously established approach, the interplay of flow rate and particle size on the NOM effect was quantified, using flow rates of 1 and 2 mL/min and particle sizes of 50 and 200 nm to represent small nanoparticles (1-100 nm) and large non-nano-microspheres (100-1000 nm) in the low-flow groundwater environment. Latex particles, Suwannee River humic acid (SRHA), and iron oxide-coated sand were used as model particles, NOM, and the aquifer medium, respectively. The quantitative results show NOM blocked more sites for large particles at a high flow rate: 1 μg of SRHA blocked 5.95 × 10(9) microsphere deposition sites at 2 mL/min but only 7.38 × 10(8) nanoparticle deposition sites at 1 mL/min. The particle size effect dominated over the flow rate, and the overall effect of the two is antagonistic. Granule-scale visualization of the particle packing on the NOM-presented sand surface corroborates the quantification results, revealing a more dispersed status of large particles at a high flow rate. We interpret this phenomenon as a polydispersivity effect resulting from the differential size of the particles and NOM: high flow and a high particle size enlarge the ratio of particle-blocked to NOM-blocked areas and thus the NOM blockage. To our knowledge, this is the first model-assisted quantification on the interplay of NOM, flow rate, and particle size on colloid transport. These findings are significant for nanorisk assessment and nanoremediation practices.

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Section: Methodssupporting

confidence: 87%

Section: Methodssupporting

confidence: 84%

Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling

Yang

Zhang

Chen

et al. 2015

Environ. Sci. Technol.

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“…In a simple system consisting of only pure water and clean silica sand, positively charged PNPs will be attracted to and retained by the negatively charged sand without any additional intervening processes. , Conversely, the electrostatic repulsion between negatively charged PNPs and the sand will stabilize the PNPs in solution and may improve their mobility. ,,,, Unmodified polystyrene (100 nm) nanoparticles, for example, were found to exhibit behavior similar to a conservative tracer during transport through a natural desert soil (with low OM and clay content) at a low ionic strength and a high pH, which is attributed to the negative ζ potential of both the soil and PNPs . When the fluid phase has a more complex composition, the presence of metal cations can limit the electrostatic repulsion between the particles through charge screening, increasing the relative effects of van der Waals interactions between PNPs and the substrate. ,,, Cations, like Ca 2+ , and dissolved organic matter may also be adsorbed by the PNPs and/or the substrate, mitigating the repulsion between them and facilitating sorption, or directly causing adsorption via cation or polymer bridging. ,,,, While DOM typically limits PNP mobility in soils, particulate organic matter, and in some cases even DOM, can actually increase PNP mobility by becoming attached to the PNP and/or substrate surfaces, resulting in steric or electrostatic repulsion between the PNPs and the substrate. ,,− While clean sand can provide initial insights into the mechanisms affecting PNP mobility in soil, natural systems are much more complex.…”

Section: Pnp Transport In Soil and Sedimentmentioning

confidence: 99%

The Mobility of Plastic Nanoparticles in Aqueous and Soil Environments: A Critical Review

2020

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Plastic nanoparticles (PNPs) are now widely recognized as a significant, and ever increasing, hazard in aquatic and soil environments. These particles, defined here as plastics <1000 nm across their largest dimension, are released into the environment both as primary products and through the degradation of larger plastic waste. They have the potential to be highly mobile, given their small size, which raises concerns about their global spread. Furthermore, PNPs are capable of adsorbing a variety of other pollutants, including heavy metals, pharmaceuticals, and pesticides, and in doing so may increase the mobility of these harmful materials. Dozens of studies focused on the toxicity of PNPs with and without other adsorbed contaminants for organisms from algae to humans have been published in the past few years. It is also critical to understand the transport of these particles in different environments to fully assess the threat that they pose. In this critical review, we discuss the behavior of suspended PNPs in aqueous systems and water-saturated soil/sediment with a particular emphasis on the processes that may alter their mobility. We describe how PNPs of different sizes and surface functionalities interact with the typical constituents of natural solutions, including metal cations, dissolved and particulate organic matter, and inorganic colloids. These variables all affect PNP aggregation in a range of complex, interrelated ways and can ultimately lead to particle sedimentation and removal from the mobile fluid phase. We also discuss the reactive transport of these PNPs, and PNP aggregates, through soils and sediments, during which PNP mobility can be limited by physical straining and/or attachment to the substrate. Finally, we conclude with some suggested future directions for research within this field, particularly the need for direct measurement of PNP abundances and characteristics in real environmental samples, which to date has been severely limited due to analytical challenges. Plastic nanoparticles do present a serious potential threat to the environment and even to human health, and a thorough understanding of the transport and mobility of these pollutants is critical in assessing these risks.

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“…Adsorbed organics on surfaces have frequently been reported to create a brush-like surface that diminishes colloid retention and/or increases colloid stability (Kretzschmar and Sticher, 1997;Yang et al, 2010Yang et al, , 2011Yang et al, , 2013Yang et al, , 2014Flynn et al, 2012). This diminished colloid retention or increased stability in the presence of adsorbed organics has typically been attributed to steric repulsion which creates a large energy barrier to interaction in a primary minimum (Espinasse et al, 2007;Han et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Types and Amounts of Nanoscale Heterogeneity on Bacteria Retention

Bradford

Sasidharan

Kim

et al. 2018

Front. Environ. Sci.

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Interaction energy calculations that assume smooth and chemically homogeneous surfaces are commonly conducted to explain bacteria retention on solid surfaces, but experiments frequently exhibit signification deviations from these predictions. A potential explanation for these inconsistencies is the ubiquitous presence of nanoscale roughness (NR) and chemical heterogeneity (CH) arising from spatial variability in charge (CH1), Hamaker constant (CH2), and contact angles (CH3) on these surfaces. We present a method to determine the mean interaction energy between a colloid and a solid-water-interface (SWI) when both surfaces contained binary NR and CH. This approach accounts for double layer, van der Waals, Lewis acid-base, and Born interactions. We investigate the influence of NR and CH parameters and solution ionic strength (IS) on interaction energy profiles between hydrophilic and hydrophobic bacteria and the SWI. Increases in CH1 and CH3 reduce the energy barrier and create deeper primary minima on net electrostatically unfavorable surfaces, whereas increasing CH2 diminishes the contribution of the van der Waals interaction in comparison to quartz and makes a more repulsive surface. However, these roles of CH are always greatest on smooth surfaces with larger fractions of CH. In general, increasing CH1 and CH3 have a larger influence on bacteria retention under lower IS conditions, whereas the influence of increasing CH2 is more apparent under higher IS conditions. However, interaction energy profiles are mainly dominated by small fractions of NR, which dramatically lower the energy barrier height and the depths of both the secondary and primary minima. This significantly increases the relative importance of primary to secondary minima interactions on net electrostatically unfavorable surfaces, especially for conditions that produce small energy barriers on smooth surfaces. Energy balance calculations indicate that this primary minimum is sometimes susceptible to diffusive removal depending on the NR and CH parameters.

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Comparison of enhanced microsphere transport in an iron-oxide-coated porous medium by pre-adsorbed and co-depositing organic matter

Cited by 11 publications

References 43 publications

Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling

Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling

The Mobility of Plastic Nanoparticles in Aqueous and Soil Environments: A Critical Review

Comparison of Types and Amounts of Nanoscale Heterogeneity on Bacteria Retention

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