Impact of Water Chemistry (pH and Inoic [i.e. Ionic] Strength) on Colloid Transport Through Porous Medium PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Impact of Water Chemistry (pH and Inoic [i.e. Ionic] Strength) on Colloid Transport Through Porous Medium PDF full book. Access full book title Impact of Water Chemistry (pH and Inoic [i.e. Ionic] Strength) on Colloid Transport Through Porous Medium by Sandip Raman Patil. Download full books in PDF and EPUB format.
![Impact of Water Chemistry (pH and Inoic [i.e. Ionic] Strength) on Colloid Transport Through Porous Medium PDF](https://books.google.com/books/content/images/frontcover/4iFsnQAACAAJ?fife=w150-h200)
Author: Sandip Raman Patil
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
ABSTRACT: Colloid transport is believed to be controlled by their interactions with the porous media. The dominating forces are the electrostatic interactions that are determined by colloid surface charge density. Although it is well accepted that electrostatic interactions between colloids and the surrounding environment play a very important role in controlling colloid retention in porous media, it is not clear how pH and ionic strength impact the electrostatic forces and the subsequent colloid transport. To have a better understanding of the impact, column colloid transport experiments were conducted under variable pH and ionic strength conditions. Based on the column experiments, colloid deposition and transport were quantified using the advection-dispersion equation and linked to solution pH and ionic strength. Finally, the repulsive electrostatic interactions between the colloids and the sediments were evaluated for different pH and ionic strength conditions, which were related to colloid transport observations. Results of this research are of importance to advancing the understanding of colloid facilitated heavy metal and organic contaminant transport in the subsurface.
![Impact of Water Chemistry (pH and Inoic [i.e. Ionic] Strength) on Colloid Transport Through Porous Medium PDF](https://books.google.com/books/content/images/frontcover/4iFsnQAACAAJ?fife=w80-h100)
Author: Sandip Raman Patil
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
ABSTRACT: Colloid transport is believed to be controlled by their interactions with the porous media. The dominating forces are the electrostatic interactions that are determined by colloid surface charge density. Although it is well accepted that electrostatic interactions between colloids and the surrounding environment play a very important role in controlling colloid retention in porous media, it is not clear how pH and ionic strength impact the electrostatic forces and the subsequent colloid transport. To have a better understanding of the impact, column colloid transport experiments were conducted under variable pH and ionic strength conditions. Based on the column experiments, colloid deposition and transport were quantified using the advection-dispersion equation and linked to solution pH and ionic strength. Finally, the repulsive electrostatic interactions between the colloids and the sediments were evaluated for different pH and ionic strength conditions, which were related to colloid transport observations. Results of this research are of importance to advancing the understanding of colloid facilitated heavy metal and organic contaminant transport in the subsurface.
Author: Fritz H. Frimmel
Publisher: Springer Science & Business Media
ISBN: 3540713395
Category : Science
Languages : en
Pages : 294
Get Book Here
Book Description
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.
Author: Sandip Raman Patil
Publisher:
ISBN:
Category : Civil engineering
Languages : en
Pages :
Get Book Here
Book Description
ABSTRACT: National Water-Quality Assessment Program (NAWQA) was designed just after the U.S. Geological was established. The primary objective of the NAWQA was to understand the key processes controlling contaminant fate and transport into the Nation's water resources. In particular, wide use of pesticides and fertilizers in agricultural field can impact on the quality of surface and ground waters. Contaminants can be carried to the water bodies by several ways. In colloid-facilitated transport process colloidal particles serves as a transport media for the contaminants. Colloid release from the agricultural soil under unsaturated conditions is controlled by the hydrodynamic force, capillary force and electrostatic force that is determined by the solution chemistry in terms of solution ionic strength and pH. In this research, colloid release from the agricultural soil was investigated using an intact soil column collected from an agricultural site in Gadsden County of Florida. Colloid release was monitored and the colloid release curve was simulated using an implicit, finite-difference scheme to obtain the colloid release coefficient. It was found that the hydrodynamic force and electrostatic force overcame the capillary force under the experimental conditions of this research and consequently, colloids were released. For the colloid release, solution chemistry played a key role by controlling the colloid repulsive electrostatic force within the pore system. Colloid release exponentially decreased with the increase of solution ionic strength and increased with the increase of solution pH. Colloid release was finally found to be correlated to the colloid repulsive electrostatic force within the pore system, i.e., the greater the repulsive electrostatic force, more colloids were released. In situ colloid mobilization and transport has been studied under both saturated and unsaturated conditions. In saturated conditions, the controlling parameters are solution ionic strength and pH. Colloid mobilization and transport have been modeled by the advection-dispersion equation with a first-order colloid release. The inverse version of these models can provide a platform to estimate transport parameters based on transport observations. In this research, we taken the advantages of existing contaminants transport models by fully utilizing them to investigate colloid interactions with the surrounding environment and provide parameter constraints for colloid transport modeling applications under saturated conditions. In natural systems, colloids present a potential health risk due to their propensity to associate with contaminants or in the case of certain biological colloids, inherent pathogenic nature. Although colloidal interactions have been studied for many years and much has been learned about the physical and chemical processes that control colloid retention, there still remains significant uncertainty about the processes that govern colloid release. The aim of this study was to investigate the release of in situ colloids as a function of soil depth. Colloid release from intact agricultural soil columns with variable length was investigated. Colloid release curves were simulated using an implicit, finite-difference scheme and colloid release rate coefficient was found to be an exponential function of the soil depth. The simulated results demonstrated that transport parameters were not consistent along the depth of the soil profile. Wetting agents wet hydrophobic soil by lowering the cohesive and/or adhesive surface tension, which allows the water to spread out more evenly and allows for better penetration into the hydrophobic soils. While enhancing water penetration, wetting agent applications may bring adverse impact on the soil and groundwater at the same time. The residual organic phase in the soil pores poses a long-term source of groundwater contamination. After use, residual wetting agents and their degradation products are discharged to groundwater or directly to surface waters, then dispersed into different environmental compartments. In order to assess their environmental risks, we need to understand the distribution, behavior, fate and biological effects of these surfactants in the environment. This research was designed to investigate the application of nonionic wetting agents in agricultural soils. Performance of nonionic surfactants in intact soil columns collected from agricultural soils was explored and related to the soil and wetting agent properties. In addition, the impact of the organic concentration of wetting agent fate and transport was investigated. The transport of wetting agents in the agricultural soil columns was simulated using the proposed transport models and subsequently, the effect of organic compounds on wetting agent transport was quantified.
Author: Jacques Buffle
Publisher: CRC Press
ISBN: 1351270788
Category : Science
Languages : en
Pages : 357
Get Book Here
Book Description
Environmental Particles, Volume 2 presents a review of the sampling, characterization, and behavior of particles in air, water, sediments, and solids. The book analyzes the formation, aggregation, transport, and conversion of particles, and evaluates the capabilities of physical and chemical analytic methods. It also discusses physicochemical properties of environmental particles, their spectroscopic characterization and colloid chemical properties, and how they affect biochemical and toxicological processes. This book is an important reference for environmental chemists, limnologists, oceanographers, air and soil scientists, analytical chemists, environmental engineers, students, and more.
Author: Pan Ming Huang
Publisher: CRC Press
ISBN: 1439803048
Category : Science
Languages : en
Pages : 2272
Get Book Here
Book Description
An evolving, living organic/inorganic covering, soil is in dynamic equilibrium with the atmosphere above, the biosphere within, and the geology below. It acts as an anchor for roots, a purveyor of water and nutrients, a residence for a vast community of microorganisms and animals, a sanitizer of the environment, and a source of raw materials for co
Author:
Publisher:
ISBN:
Category : Colloids
Languages : en
Pages : 40
Get Book Here
Book Description
Author: John McCarthy
Publisher: CRC Press
ISBN: 9780873718288
Category : Technology & Engineering
Languages : en
Pages : 412
Get Book Here
Book Description
This valuable resource discusses several strategies of manipulating colloids for environmental restoration, identifies advantages and disadvantages of each strategy, and considers obstacles limiting the application of each strategy. Approaches evaluated include the following: Chemical modification of subsurface systems to mobilize or deposit colloids in situ Altering the mobility of microorganisms to improve delivery of microbes for bioremediation Manipulating colloids or biocolloids (bacteria) to change aquifer permeability to either enhance bioremediation or create in situ barriers Introducing modified colloids, surfactants, and emulsions to control colloid mobility or to increase recovery of sorbed contaminants by pump and treat methods Manipulation of Groundwater Colloids for Environmental Restoration also contains short, focused research reports on specific studies relevant to the various approaches under consideration. Subjects covered range from mobility of organic macromolecules by controlled field injection experiments to new techniques that investigate surface chemistry and aggregation of inorganic colloids. Other topics discussed include the depositional behavior and transport of biocolloids in porous media, surfactants as modifiers of surface binding sites on colloids, and genetic engineering of microorganisms to serve as contaminant-scavenging biocolloids. Manipulation of Groundwater Colloids for Environmental Restoration is an excellent resource for research scientists in hydrology, chemistry, and microbiology; environmental consultants; regulators; environmental engineers; bioremediation microbiologists; and engineers.
Author:
Publisher:
ISBN: 9780549925293
Category : Colloids
Languages : en
Pages :
Get Book Here
Book Description
Colloid-facilitated transport of contaminants and transport of biocolloids (e.g., viruses and bacteria) in soil porous media are acknowledged environmental issues. Understanding of the mechanisms and parameters controlling colloid transport is important for protection of soil and groundwater resources from bio- and chemical contamination and improvement of remediation practices. For research purposes, unsaturated soil is often represented with idealized porous media, which facilitates conceptual understanding of colloid transport and retention mechanisms. Major colloid retention mechanisms include retention at solid-water interface (SWI), at air-water interface (AWI), and on the contact line. Additional colloid retention occurs as a result of straining in the narrow, compared to colloid size, regions of porous media. Colloid retention at AWI and colloid retention on the contact line are characteristic of unsaturated porous media and are currently associated with substantial uncertainty in colloid transport literature regarding their respective roles and contributions to overall colloid retention. In order to distinguish colloid retention mechanisms, traditional laboratory column experiments often require supplementary pore-scale investigation. The focus of this research was to investigate colloid retention at AWI and contact line at the pore scale. In this work, open capillary channels and microfluidic channels were utilized as models of soil capillaries, and behavior of colloids was visualized directly with confocal microscope. The employed channels have angular cross sections, which is in agreement with a more realistic angular representation of soil capillaries. The open-channel configuration served as a model of free-surface flow in microscopic grooves and corners in soil while the microfluidic channels were used to represent two-phase (air-water) flow in soil such as during drainage and infiltration events. To acquire qualitative and quantitative information, experimental confocal images were recorded and systematically processed with advanced imaging software. Colloid behavior in open channels with square cross section was investigated both in static and dynamic regimes. During flow in the channel, colloid movement occurred along the contact line, which acted as a colloid accumulation site due to reduced velocities in the contact line region. For this channel configuration, flow stagnation at AWI was observed, which promoted colloid retention at AWI. The maximum velocity and therefore maximum colloid transport were observed inside the channel. These observations indicated the importance of hydrodynamic conditions in affecting colloid retention. In the static regime, effects of a number of physicochemical parameters on colloid retention at AWI, including ionic strength, colloid contact angle, and surface tension (addition of surfactant), were investigated. It was shown that retention of colloids at AWI was dependent on electrostatic conditions and colloid contact angle and varied to a lesser extent with addition of non-ionic surfactant. The retention of colloids at AWI in a static system was analyzed with extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and was attributed to a possible secondary energy minimum retention. In microfluidic channels, which have a trapezoid cross section, AWI was observed as a two-phase boundary. In such configuration, both AWI and contact line move in the flow direction. It was shown that colloid retention on the contact line was considerably affected by hydrodynamic conditions. Colloid retention at AWI occurred primarily via involvement of colloids, which were previously deposited on the wall, with the moving contact line. Direct retention of dispersed colloids at AWI was not observed. The moving AWI was realized both as receding (air) and advancing (water) fronts, which allowed examination of the role that AWI played in colloid mobilization under both drainage and infiltration scenarios. Experimental results were considered in view of colloid interaction energies as well as forces acting on colloids at the sites of interest. Both experimental and theoretical findings resulted in improved understanding of colloid retention at AWI and contact line in the considered configurations, i.e., open channel and two-phase flows. The results of this research provide mechanistic understanding of colloid retention and can be applied in interpretation of observations at larger scales and in modeling of colloid transport in unsaturated porous media. This dissertation is accompanied with supplementary material showing representative video images and illustrating the discussed processes. System requirements for viewing the video: Windows Media Player or RealPlayer.
Author: K. S. Birdi
Publisher: CRC Press
ISBN: 1420007203
Category : Science
Languages : en
Pages : 772
Get Book Here
Book Description
The third edition of this besteller covers the latest advancements in this rapidly growing field. Focusing on analyses and critical evaluation of the subject, this new edition reviews the most up-to-date research available in the current literature. International contributors offer their perspectives on various topics including micellar systems, mi
Author: David A. Sabatini
Publisher:
ISBN:
Category : Language Arts & Disciplines
Languages : en
Pages : 274
Get Book Here
Book Description
Transport and remediation of subsurface contaminants: introduction; Colloid deposition in porous media and an evaluation of bed-media cleaning techniques; Deposition of colloids in porous media: theory and numerical solution; Surface-charge repulsive effects on the mobility of inorganic colloids in subsurface systems; Colloid transport and the gas-water interface in porous media; Colloid remediation in groundwater by polyelectrolyte; Removal of chromate from aqueous strems by ultrafiltration and precipitation; Potential for bacterial remediation of waste sites containing selenium or lead; Heap leaching as a solvent-extraction technique for remediation of metals-contaminated soils; Factors affecting surfactant performance in groundwater remediation applicationsInfluence of surfactant sorption on capillary pressure-saturation relationships; Surfactant-enchanced solubilization of tetrachloroethylene and degradation products in pump and treat remediation; Solubilization and biodegradation of Hydrophobic organic compounds in soil-aqueous systems with nonionic surfactants; sorption of hydrophobic organic compounds and nonionic surfactants with subsurface materials; Field tests of surfactant flooding: mobility control of dense nonaqueous-phase liquids; Landfill leachate effects on transport of organic substances in aquifer materials; Clay and immiscible organic liquids: greater capillary trapping of the organic phase; Exposure assessmnet modeling for hydrocarbon spills into the subsurface: sensitivity to soil properties.
