Download or read book Deposition of Colloids in Saturated Porous Media and Simple Shear Systems written by Christina N. Brow and published by . This book was released on 2005 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluating the Role of the Secondary Energy Minimum in Colloid Deposition and Release in Saturated Porous Media written by Qing Ye and published by . This book was released on 2010 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Transport and release of carboxylate-modified polystyrene microspheres of two sizes (36nm and 490nm) in saturated quartz sand under steady flow conditions were investigated in this study. The interaction energy profiles and classic DLVO framework were set up based on measurements and characterization of both particles and sand grains to evaluate and explain the colloidal behavior in the porous media. Emphasis was focused on the roles of the secondary energy minimum and effects of solution chemistry. It was found that the deposition of both colloids displayed apparent ionic strength dependence, and generally the higher ionic strength values were, the more deposition occurred. All the breakthrough curves had extended tailing, which was ascribed to the reversible colloid deposition (release from the secondary minimum) under hydrodynamic drag interactions. The 36nm colloids were observed to have retarded initial breakthrough at high ionic strength, similar to the reversible adsorption of solute species. This was interpreted to result from readily reversible deposition in the secondary minimum. The 490nm colloids did not have such delayed breakthrough and instead displayed slight size exclusion effects indicative of straining. The influence of heterogeneities on colloid deposition and release was also considered. For example, surface roughness appeared to be an important mechanism for 36nm colloid deposition at low ionic strength. At high ionic strength, however, the secondary and even primary minima dominate colloid deposition and release. Both straining and the secondary minimum were enhanced at greater ionic strength. The profile of retained colloids measured for the 490nm colloids transitioned from hyper-exponential to non-monotonic styles as the ionic strength increased. This reflects a transition from straining-dominated deposition to deposition involving both straining and the secondary minimum. Plausible release mechanisms were deduced based on experimental observations. The final release step, which involved the transition from the existence of the secondary minimum to no secondary minimum, was the most important step. During this transition, no secondary minimum association sites were available for colloid retention, and the only colloid retention sites left were likely straining sites such as grain-grain contact points. The release behavior indicated that global release was the net of local release and subsequent redeposition. A conceptual model was developed to include the assumptions of non-contacting deposition, critical ionic strength ranges, distributed nature of interaction energies, as well as squeezing-induced local colloid release mechanisms.

Download or read book Colloid Transport in Saturated Porous Media written by Ann Mathew and published by . This book was released on 2007 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three dimensional Pore scale Visualization and Trajectory Analysis of Colloid Transport and Retention in Saturated Porous Media written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The research contained in this thesis investigates the transport and deposition behavior of 1.1 and 3ìm carboxylate-modified microspheres in saturated porous media under unfavorable deposition conditions. Colloid motion and deposition patterns are visualized in three dimensions using a high-speed confocal microscope and micromodels packed with glass beads or sand grains. This study specifically focuses on colloid behavior in the grain-to-grain contact region, which has been suggested in previous studies as an important location for colloid retention under unfavorable conditions. The use of the high resolution confocal microscope allowed the distinction of two types of colloidal retention that can occur in the grain-to-grain contact region and showed that single surface retention was much more abundant than retention on two surfaces (straining). This study also demonstrated that both the extent and rate of straining are enhanced by increasing flow rate. In addition to obtaining qualitative descriptions of colloid deposition patterns, this study is the first to provide quantitative analysis of the motion of individual colloidal particles leading to the construction of three-dimensional colloid trajectory in both the bulk phase and grain-to-grain contact regions. The results demonstrated the dominant effects of hydrodynamics on colloid motions, i.e., most colloids entering the grain-to-grain contact region tend to follow the streamlines to detour the contact point, making straining a transport-limited process. Retention in the secondary energy minimum can significantly retard colloid movement but this association was not strong enough to keep the retained colloid inside the energy well over time. Colloid retention and movement through sand-packed sand micromodels were more complex compared to those packed with glass beads due to the more complex hydrodynamic conditions resulting from the irregular packing geometry and surface roughness of sand. These results suggest that theoretical torque analysis based on the idealized scenarios is not a suitable approach for describing colloid transport and deposition under unfavorable conditions in complex natural porous media.

Download or read book An Experimental Investigation on Colloid Straining Within Saturated Heterogeneous Porous Media written by Alexis A. Porubcan and published by . This book was released on 2009 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of Colloid Transport and Deposition Dynamics in Porous Media written by Jeffrey Y. Chen and published by . This book was released on 1998 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Colloid Transport and Attenuation in Saturated Porous Media written by Xinyao Yang and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloids refer to particles or macromolecules with at least one dimension of 1nm 1m. A wide range of environmental particles fall within this category including microorganisms, nanoparticles, and mineral precipitates. Understanding colloid fate and transport in porous medium not only permits more effective protection of water supplies, but also allows for the development of more effective pollutant remediation strategies. Organic matter (OM) complicates colloid behaviour. To date the influence of OM on colloid mobility in porous media has been largely qualitative. This book presents research leading to the development of multiple-pulse column techniques that may be integrated with mathematical models to quantify the effects of OM on particulate colloid attenuation in saturated porous medium. Research has investigated how two groups of environmental organic compounds, humic acids and proteins, influence particulate colloid attenuation by saturated sand. Study findings may shed light on complex colloidal behaviour in organic matter impacted environment and be useful to professionals in contaminant hydrogeology, environmental remediation, and wastewater treatment.

Download or read book Dynamics of Colloid Transport and Deposition in Heterogeneous Granular Porous Media written by Chun-Han Ko and published by . This book was released on 1999 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics of Colloid Deposition in Granular Porous Media written by Menachem Elimelech and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Colloid Deposition and Aggregation in the Presence of Charged Collectors written by Behnam Sadri and published by . This book was released on 2015 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloidal-collector interactions are of fundamental importance in separation and filtration technologies. Here, the effect of collector grains on the behavior of colloidal particles was studied in two different experimental systems, i.e., column studies with stationary collectors and batch mixing to study hetero aggregation. Polystyrene latex beads, 100 nm diameter, and soda lime glass beads, with two different diameters of 212-300 $\mu$m and 710-1180 $\mu$m, were employed as colloidal particles and collector grains, respectively. Column experiments were performed to understand fate of colloidal particles in the porous medium. There are three major phenomena that control colloidal transport in porous media: Deposition, aggregation, and straining. These three distinct types of particle dynamics in porous media were studied by adjusting physicochemical properties of colloidal suspension. Furthermore, the effect of washing the collector beads was studied. Batch experiments, in which known amount of collector grains are added to colloidal suspension with known concentration, are designed to investigate more collector-colloids interaction role in transport dynamics of colloidal particles. UV-Vis spectroscopy and dynamic light scattering techniques are employed to understand both deposition and aggregation of colloidal particles in the vicinity of collector grains. Results obtained by dynamic light scattering revealed that aggregation is the predominant factor in this colloidal system. The possible sources for this type of behavior are also tackled by undertaking controlled experiments. In the batch experiments, ions leaching from the surface of glass beads, effect of mixing, and glass beads presence are confirmed as the three major reasons behind the aggregation of colloidal particles.

Download or read book Colloidal Transport in Porous Media written by Fritz H. Frimmel and published by Springer Science & Business Media. This book was released on 2007-05-26 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the basics of abiotic colloid characterization, of biocolloids and biofilms, the resulting transport phenomena and their engineering aspects. The contributors comprise an international group of leading specialists devoted to colloidal sciences. The contributions include theoretical considerations, results from model experiments, and field studies. The information provided here will benefit students and scientists interested in the analytical, chemical, microbiological, geological and hydrological aspects of material transport in aquatic systems and soils.

Download or read book Colloid Transport in Saturated and Unsaturated Porous Media written by Jun Qi and published by . This book was released on 2004 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Van Der Waals and Hydrodynamic Interactions on Colloid Deposition in Porous Media written by Chee-Wei Tsao and published by . This book was released on 1992 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Current Awareness in Particle Technology written by and published by . This book was released on 1996 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particle Deposition and Aggregation written by M. Elimelech and published by Elsevier. This book was released on 1998-08-07 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deposition and aggregation of small solid particles are encountered in many natural and industrial environments. Whether it be deposition of particles onto a surface immersed in a liquid suspension or aggregateion of individual particles, these processes are of enotmous significance. They are vital to the manufacture of magnetic tape, purification of water using packed bed filters, selective capture of solids, cells and macromolecular species, and many other applications. This book presents a unified approach to the measurement, modelling and simulation of these processes, bringing together the disciplines of colliod and surface chemistry, hydrodynamics, and experimental and computational methods. It will be required reading for graduates working in process and environmental engineering, postgraduates involved in industrial R & D and for all scientists wishing to gain a more detailed and realistic understanding of process conditions in these areas.

Download or read book Progress in Adhesion and Adhesives written by K. L. Mittal and published by John Wiley & Sons. This book was released on 2015-07-27 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on the 13 review articles written by subject experts and published in 2014 in the Journal Reviews of Adhesion and Adhesives. The rationale for publication of this book is that currently the RAA has limited circulation, so this book provides broad exposure and dissemination of the concise, critical, illuminating, and thought-provoking review articles. The subjects of the reviews fall into 4 general areas: 1. Polymer surface modification 2. Biomedical, pharmaceutical and dental fields 3. Adhesives and adhesive joints 4. General Adhesion Aspects The topics covered include: Adhesion of condensed bodies at microscale; imparting adhesion property to silicone material; functionally graded adhesively bonded joints; synthetic adhesives for wood panels; adhesion theories in wood adhesive bonding; adhesion and surface issues in biocomposites and bionanocomposites; adhesion phenomena in pharmaceutical products and applications of AFM; cyanoacrylate adhesives in surgical applications; ways to generate monosort functionalized polyolefin surfaces; nano-enhanced adhesives; bonding dissimilar materials in dentistry; flame treatment of polymeric materials—relevance to adhesion; and mucoadhesive polymers for enhancing retention of ocular drug delivery.

Download or read book Bubbles Drops and Particles written by R. Clift and published by Courier Corporation. This book was released on 2013-04-22 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume offers a unified treatment and critical review of the literature related to the fluid dynamics, heat transfer, and mass transfer of single bubbles, drops, and particles. 1978 edition.