Colloidal phenomena in porous media, natural or engineered, are important in a breadth of science and technology applications, but fundamental understanding is hampered by the difficulty in measuring colloid deposit morphology in situ. To partially address this need, this paper describes a static light scattering apparatus using a flow cell filled with refractive index matched (RIM) porous media, allowing real-time measurement of colloidal phenomena as a function of depth within the flow cell. A laser interacts with the colloids in the pore space and their structures, but not with the RIM media. The intensity of scattered light is measured as a function of scattering angle, which allows characterization of colloid deposit morphology as a fractal dimension and a radius of gyration. In parallel, fluid discharge rate and pressure drop are recorded to determine permeability, a key parameter for any application involving flow through porous media. This apparatus should prove useful in any application requiring characterization of colloidal phenomena within porous media. Additionally, this paper describes how to use granular Nafion as RIM porous media.
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http://dx.doi.org/10.1063/1.4935576 | DOI Listing |
Sensors (Basel)
January 2025
Faculty of Architecture and Civil Engineering, Karlsruhe University of Applied Sciences, 76133 Karlsruhe, Germany.
Engineers, geomorphologists, and ecologists acknowledge the need for temporally and spatially resolved measurements of sediment clogging (also known as colmation) in permeable gravel-bed rivers due to its adverse impacts on water and habitat quality. In this paper, we present a novel method for non-destructive, real-time measurements of pore-scale sediment deposition and monitoring of clogging by using wire-mesh sensors (WMSs) embedded in spheres, forming a smart gravel bed (GravelSens). The measuring principle is based on one-by-one voltage excitation of transmitter electrodes, followed by simultaneous measurements of the resulting current by receiver electrodes at each crossing measuring pores.
View Article and Find Full Text PDFCO flooding plays a crucial role in enhancing oil recovery and achieving carbon reduction targets, particularly in unconventional reservoirs with complex pore structures. The phase behavior of CO and hydrocarbons at different scales significantly affects oil recovery efficiency, yet its underlying mechanisms remain insufficiently understood. This study improves existing thermodynamic models by introducing Helmholtz free energy as a convergence criterion and incorporating adsorption effects in micro- and nano-scale pores.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Physics, Faculty of Natural Sciences and Informatics, Constantine the Philosopher University in Nitra, Tr. A. Hlinku 1, 94901 Nitra, Slovakia.
Experimental studies have shown that osmosis could be one of the mechanisms of water transport in porous materials that act, to a certain extent, as semipermeable membranes. In this paper, an experimental apparatus and the corresponding model to measure and determine the osmotic efficiency, , of bulk porous materials are described. Both the apparatus and model to interpret water transport in samples are modifications of those of Sherwood and Craster.
View Article and Find Full Text PDFGels
December 2024
Institute of Natural Sciences and Technosphere Safety, Sakhalin State University, 693000 Yuzhno-Sakhalinsk, Russia.
A new composite material with enhanced sorption-selective properties for uranium recovery from liquid media has been obtained. Sorbents were synthesized through a polycondensation reaction of a mixture of 4-amino-N'-hydroxy-1,2,5-oxadiazole-3-carboximidamide (hereinafter referred to as amidoxime) and SiO in an environment of organic solvents (acetic acid, dioxane) and highly porous SiO. To establish optimal conditions for forming the polymer sorption-active part and the synthesis as a whole, a series of composite adsorbents were synthesized with varying amidoxime/matrix ratios (35/65, 50/50, 65/35).
View Article and Find Full Text PDFJ Environ Manage
January 2025
BQE Water, Vancouver, BC, Canada.
Biological semi-passive mine water treatment technologies are used in the mining industry as an alternative to or in conjunction with active treatment systems to remediate mine impacted water (MIW) containing nitrate and selenium oxyanions such as selenate and selenite. In semi-passive biological treatment systems, MIW is pumped through a saturated, porous media (either a gravel bed or waste rock) which provides ample surface area for biofilm growth and the creation of anoxic, subaqueous environments. Additional nutrients and carbon sources are pumped into the system to encourage the growth of microbes that biochemically reduce selenate and selenite to insoluble reduced Se species such as selenium nanoparticles (SeNP) by respiring selenate and selenite.
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