Journal ArticleDOI
Grain Surface-Roughness Effects on Colloidal Retention in the Vadose Zone
TLDR
In this article, the role of surface roughness in governing colloid transport in the vadose zone was investigated, and it was shown that more particles are retained at lower water contents, smoother grain surfaces retain fewer colloids in the porous media under both saturated and unsaturated conditions, and the effects of surface surface rougheness diminish with increasing grain surfaces roughness.Abstract:
Work to date has raised awareness regarding the importance of transport of colloids in the vadose zone, as it is the critical connection between shallow contaminant sources and the deeper groundwater. Existing models do not predict accurately the physical conditions under which such particle transport occurs. Recent theory on capillary and friction forces acting at the air-water meniscus-solid (AWmS) interface suggests that grain roughness is an important factor in colloid retention for unsaturated media. Our main objective was to investigate the role of surface roughness in governing colloid transport in the vadose zone. Unsaturated flow cell experiments with sands of different grain roughness were performed to determine colloidal retention at the postulated AWmS interface. Two rectangular acrylic vertical flow cells (2 by 2 by 5 and 2 by 2 by 10 cm) were built to collect visual and numerical data under the effects of gravity. Colloid behavior was visualized in situ with digital bright field microscopy, effluent concentrations of colloids were measured concomitantly with spectrophotometry, and retention was quantified with mass balance analysis. From visual analysis, significant retention was observed at apparent AWmS interfaces and in zones of immobile water. An equilibrium deterministic convective-dispersion model was used and fitted to our data with fair accuracy. This study';s visual, quantitative, and statistical results show that: more particles are retained at lower water contents, smoother grain surfaces retain fewer colloids in the porous media under both saturated and unsaturated conditions, and the effects of surface roughness diminish with increasing grain surface roughness.read more
Citations
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Journal ArticleDOI
Plastics in soil: Analytical methods and possible sources
Melanie Bläsing,Wulf Amelung +1 more
TL;DR: Current knowledge on available methods for the quantification and identification of plastic in soil, the quantity and possible input pathways of plastic into soil, and its fate in soil are reviewed are reviewed to ensure the applicability of these methods for soil needs to be tested.
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Transport and Fate of Microbial Pathogens in Agricultural Settings
Scott A. Bradford,Verónica L. Morales,Wei Zhang,Ronald W. Harvey,Aaron I. Packman,Arvind Mohanram,Claire Welty +6 more
TL;DR: In this article, a number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings, and the level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources.
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Humic Acid Facilitates the Transport of ARS-Labeled Hydroxyapatite Nanoparticles in Iron Oxyhydroxide-Coated Sand
TL;DR: Consideration of the above effects is necessary to improve remediation efficiency of nHAP for metals and actinides in soils and subsurface environments.
Journal ArticleDOI
Critical role of surface roughness on colloid retention and release in porous media.
TL;DR: Results demonstrated that the density and height of NSR significantly influenced the interaction energy parameters and consequently the extent and kinetics of colloid retention and release, and yielded a much weaker primary minimum interaction compared with that of smooth surfaces.
Journal ArticleDOI
Variability of crystal surface reactivity: What do we know?
Cornelius Fischer,Cornelius Fischer,Inna Kurganskaya,Thorsten Schäfer,Andreas Luttge,Andreas Luttge +5 more
TL;DR: In this paper, the authors provide an integrated view on an important feedback process that includes surface reactivity, kink site distribution, surface roughness, surface retention, and surface inhibition as critical components.
References
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Journal ArticleDOI
Water and waste water filtration. Concepts and applications
TL;DR: In this article, a conceptual model for water and waste water filtration processes is presented and compared with the results of laboratory experiments, and applications of particle destabilization and particle transport are presented.
Journal ArticleDOI
Migration of plutonium in ground water at the Nevada Test Site
TL;DR: In this paper, it was shown that the radionuclides observed in groundwater samples from aquifers at the Nevada Test Site, where hundreds of underground nuclear tests were conducted, are associated with the colloidal fraction of the ground water.
Journal ArticleDOI
A review of non-DLVO interactions in environmental colloidal systems
TL;DR: The DLVO model has been found unable to fully describe the behavior of abiotic and abiotic colloidal behavior inaqueous media as mentioned in this paper, and it is reasonable to believe that the structure of water may participate in a more significant fashion.
Journal ArticleDOI
DLVO interaction between rough surfaces
TL;DR: In this paper, the surface element integration technique was employed to determine the interaction energy between surfaces containing morphological heterogeneity, and the effect of surface roughness on the DLVO interaction potential was investigated.
Journal ArticleDOI
Mobility and solubility of toxic metals and nutrients in soil fifteen years after sludge application
TL;DR: The increased use of sewage sludge as a fertilizer, combined with reports that large fractions of sludge-borne heavy metals cannot be accounted for several years after land application, indicates that more detailed study of potential mobility of these metals in soils is needed as mentioned in this paper.